Based on the mass of contrast tests, creep consolidation characteristics and calculating models of typical soft soil from Guangdong are systematically studied. The test results show that the deformation proportion of consolidation and secondary consolidation is related to the factors including initial load and loading ration in test, consolidation degree, water content and void ratio of soil samples. The complications of affecting secondary consolidation coefficient are loading history, loading ration and current consolidation state of soft soil. Preloading can reduce secondary consolidation coefficient. The scale between second consolidation coefficient and compression index is constant, about 0.025-0.10. Direct shear-creep characteristic is related to vertical consolidation pressure; and the creep rule presents strain hardening characteristics. Consolidation action can play down the creep effect, so the creep characteristic in triaxial test is connected with drainage condition. In coordination loading addition, the relationship between deviator stress and axial strain is nearly straight-line in CD test; but in CU test, it assumes nonlinear and there is visible yield characteristics. When the continuous loading manner is adopted in UU test, the failure strength will be improved. Bases of above results, the models of creep and consolidation are analyzed considering respectively nonlinear constitutive relationship and shear drainage condition.

Anchor reinforcement is one of the main support ways in rock engineering. How to bring out the composite reinforcing mechanism of cable to rock, as well as the invalidation mode of cable reinforcement is becoming a focus. By using the FLAC software, the transverse anchored large specimens numerical experiment under uniaxial compressive stress conditions has been done. It is shown that the cable composite reinforcing action for rock mass depends on not only the magnitude of compressive stress, but also the magnitude of cohesion on the bonding interface between rock and cable. As the decrease in cohesion on the bonding interface, the bonding interface stress and cable stress decrease correspondingly. After the cohesion on the bonding interface decreases to a certain magnitude, the cable will separate from the rock and the slide on interface will occur, i.e. the anchor reinforcement is invalid. So to enhance the cohesion on the bonding interface is an important measure for ensuring the anchor reinforcement valid. Besides, because it is difficult to manufacture the large anchored rock specimens and it is difficult to make mechanical experiments in laboratory, numerical simulation experiments have many advantages such as time-saving, economical and visua. So doing numerical simulations instead of making experiments in laboratory for anchored rock is a promising way in the future, it is valuable for generalization.

Loading rate effects on sandy soils are investigated based on the results of plane strain compression tests and triaxial compression tests. Some tests are conformed at constant but different strain rates, and the strain-stress relationships are essentially independent of different constant strain rates. To evaluate the loading-rate effects on sand, the strain rate is changed stepwise many times under otherwise monotonous loading on different types of sand specimens. It is shown that, when the strain rate suddenly changes, the stress also changes sharply with a very high stiffness, nearly elastic behavior. Then, with an increase in the strain, the stress-strain curve exhibites a marked change in the tangent modulus and gradually rejoins the essentially unique one. This feature is called viscous evanescent property.

Various stress-controlled drained and undrained monotonic shear tests on the Chinese Fujian standard sand of relative density 30 % under complex initial consolidation conditions with different stress paths are conducted by using the soil static and dynamic universal triaxial and torsional shear apparatus. The average principal stress is unchanged in the process of tests. The coefficient of intermediate principal stress and orientation of principal stress are changed so that their influences on shear behaviors of saturated sands under different drainage conditions are respectively probed. It is shown by comparison that coefficient of intermediate principal stress influences the stress-strain normalization relationship, but does not have obvious effect on volumetric deformation as well as pore-water pressure. Under the same initial condition, the deviator stress ratio decreases with the increase in coefficient of intermediate principal stress. The above-mentioned phenomena do not relate to the drainage condition. Orientation of principal stress also has remarkable influence on monotonic shear features of sands. In drained tests, variation pattern of stress-strain relationship which is associated with the orientation of principal stress depends on shear stresses on horizontal plane and vertical plane. In undrained tests, the effective deviator stress ratio attained at peak state decreases gradually with the increase in orientation angle of principal stress.

Soil structure is the key determinant of mechanical characteristics of soil. Owing to soil structure, it is obviously deficient to use the continuous mechanical theory in geotechnical materials. SHEN Zhu-jiang, who is an academician, thinks that soil structure is the key problem of soil mechanics for the 21 century. Because of the complexity of soil structure and a lack of testing methods, the quantitative index of soil structure has not been discovered. The granular material whose structural characters are comparatively simple is the subject of this article. The particle arrangement character is the embodiment of soil structure of granular material. CT and DDA are used to solve the problem of fabric measurement of granular material. Fabric information and its variety of granular material have been gained through CT triaxial test and numerical simulation in all kinds of load. It has laid a foundation for finding a reasonable fabric quantum, studying the relationship between fabric quantum and macroscopical mechanics response and discussing the deformation mechanism and mechanical characteristics of granular materials. This paper attaches more importance to introducing CT triaxial test results and the movement law of particle of granular material during the CT triaxial test.

An experimental research is done on shallow gassy sand under different confining pressures with GDS triaxial system’s 4D stress path module. The results show that there is a remarkable influence on form of SWCC considering different confining pressures and water storage capacity of unsaturated sand declines gradually with infliction and accretion of confining pressure. Finally, pressure of shallow gas reservoir with SWCC is a analyzed and forecast, and the forecasted result is higher if SWCC is used without confining pressure.

Several stable, continuous and thick incompetent beds exist in Jurassic red strata in Wanzhou，which become sliding surfaces of rock landslides easily. The cause of the approximate level red beds landslides in Wanzhou is debatable. In order to clarify that base on mechanics, creep tests have been carried out to study the rheological property of incompetent beds, and Singh-Mitchell model is used to describe the creep character of the incompetent beds. The parameters of Singh-Mitchell model are discussed, which provides the model and parameter for further research.

An extensive attention has been paid to the effect of chemical solution on rock properties. The physical and mechanical characteristics of calcareous cementitious feldspathic sandstone specimens subjected to hydrochloric acid attack were investigated by means of the accelerated corroded test.　The progressive and deteriorative mechanism of the specimens in different acid solutions is revealed. The results indicate the acid environment has strong influence on rock mechanical properties.

Fractal geometry is a method of discovering the rules such as self-similarity of irregular curves, the self-inverse of irregular figures, the self-squaring of fractal translations, the self-affine of fractal groups and so on. If it applies on the research jobs of micro-structural fractal features, some key-techniques of soil microstructure mechanic would soon be solved. To use the fractal geometry in micro-analysis of saturation soft soil, the most important thing is to get microstructure fractal features parameters such as the fractal dimension of grains, the fractal dimension of holes. With the liquid nitrogen refrigeration sample-made technique, the scan electronic microscope technique （SEM） and the image-processing-analysis and computer-vision technique，46 group samples’ microstructure fractal features parameters of saturation soft soil which withdraw from Guangdong Scientific Center are extracted. By adopting variable gradually linearization regress analyses, the relationship between the fractal features and the porosity are discussed.

A rainfall simulation system is designed and used in centrifuge modelling of rainfall-induced landslides. The configuration of this system is described in terms of techniques special for centrifuge tests. These techniques allow the system to distribute raindrops uniformly and minimize the size effect of raindrops and the inclination of raindrops due to Coriolis effects. Hence this system is able to simulate rainfall with different intensities and durations. The function of the simulation system is verified during an infiltration process in a sand slope test in the centrifuge.

A different mechanics behaviour and a different failure process are observed of the large porous sanstone with diffrent confining pressures and diffrent saturating fluids(e.g.oil and water). Laboratory tests under complex loading paths demonstrate that a critical value of confining pressure is proved to exist, when the confining pressure increases, the main pressure-shear failure is changed into slough failure. In this paper, two failure throries are used to explain failure processes of large porous sandstone with water saturation and oil saturation respectively through an analysis of the results of laboratory tests. A constitutive model of the saturating sandstone with different fluids of oil and water is established by using the typical plasticity, and 3-dimensional nonlinear FEM is used to check the elastoplastic model based on the laboratory tests. The numerical results show that the laboratory tests are good in agreement with the mumerical simulation results by using the model of the paper, and the several failure mechanisms under complex loading paths and the additional subsidence of large porous saturating sandstone from oil exploration by hydraulic grouting are also simulated well.

In order to testify the mechanism of deeply buried anti-slide piles to reinforce the slope, the finite element method is used to analyze the experiment, the distribution and magnitude of lateral force on the piles and the distribution and magnitude of lateral force on the top of the pile are computed, and the safe coefficient varying with pile length from which the least length of deeply buried anti-slide piles meeting the needs of design is acquired. It shows that the result calculated by the finite element method is close to that got from the experiment. It proves the feasibility of designing the deeply buried anti-slide piles by the finite element method.

The western Route Project for China’s South-to-North Water Transfer is to divert 2×1010 m3 water annually from the upper of the Yangtze River to the Yellow River, which will bring relief to the drought-ridden northwestern and northern parts of China. Engineering geological investigation has discovered the complicated geological conditions, such as polytype rocks, overgrown folding, numerous north-western fractures and even active fractures, etc., which will have great effect on the slope stability of the high dams, the excavation of tunnels and caves, and earthquake effect, etc. To find out the mechanical properties of these rock masses, several representative sections were chosen to carry out field tests, such as wave-velocity test and large-scale shear test(500 mm?500 mm?350 mm), etc. The means and procedure of field shear test were expounded and the relation curves of shear stress to displacement and normal stress to shear stress have been obtained. And then, the shearing strength and shear strength of rocks obtained from field shear test were compared with laboratory test results through a slope stability analysis. The strength parameters got from field large-scale shear test is of utmost importance to the slope stability analysis and the optimum design.

Considering the fact that the super-long pile groups are used very often and lucubrated less, three pile group models with deferent pile spaces are designed and done. Based on the model test data of super long-pile groups, the load transfer mechanism and the bearing behavior are analyzed. The relations between the pile group efficiency and pile spacing, between the pile capacity and pile spacing and between the skin friction and pile spacing are obtained. Through the axial force of super-long pile, the valid length problem is researched into. Results above are provided as important references to the theoretical research and technical application of super-long pile groups.

The Great Wall was announced as the first batch of key cultural relic unit under State Protections by State Department in 1961, and was listed as the world cultural heritage by UNESCO in 1987. And these constructions are humankind’s precious cultural heritage, and their valuable artistic value is rare worldwide. Through the compression test, the shear strength test and the infiltrate test, the results of test indicate that the compression strength and the shear strength increases with the PS material consistency and the reinforcement times, and that he PS meterials can be multiple application. At the same time, the results show that the 7 % PS materials is the best consistency to consolidating the soil of the Great Wall. In addition, the permeability coefficient of the reinforced sample decreases and the permeability meets the requirements of preservation of cultural relics. By a comprehensive analysis, the 3 %—5 % of PS is suitable for consolidating the wall whose dry density is 1.5—1.7 g•cm-3, but 5 %—7 % of PS is fit for consolidating the wall whose dry density is 1.3—1.50g•cm-3. In sum, the key to protecing ruins is choosing the suitable PS consistency material and consolidation times in order to enhancing penetrability of PS material. So this reinforced method could be effective in protecting the Great Wall of Qin Dinasty in the Warring States in Northwest China.

Based on the fatigue damage tests of rock-soil materials, a new mathematic model of the fatigue damage of rock-soil material is proposed by using system analysis method and signal process technique and the parameter of fatigue damage is defined by means of bulk tests. The results show that damage parameter defined is susceptible and can trace effectively damage process of the samples. The damage process is divided into crack pullulating, crack expanding and crack high-speed expanding stage. Moreover, the relation curve between damage parameter and cycle times shows that the fatigue age of cement samples which has the same adding cement ratio and age is different. The damage process of the sandstones which have different components is not completely similar, even though their fatigue age is the same

Taking a bay project for example, the experiment scheme of dynamic consolidation method on hydraulic filled sand is introduced in detail. The increasing and duration laws are analyzed. Before and after the experiment all kinds of in-situ tests and soil mechanics laboratory tests are carried out in order to make a conclusion of the efficiency of foundation improvement by dynamic consolidation method, and the effective depth of the improvement of foundation is calculated so as to provide an example for such engineering designs.

For the instability landslide in the Three Gorges Reservoir region, the change of the reservoir water level, atmospheric precipitation and other factors arising from the impact of human activities will be the chief reasons. Landslide sliding zone which repeatedly immersed in water under its intensity is a large number of ancient landslide or produce new landslide in the region. Based on the slide belt Qianjiangping landslide in wet-dry cycle test (DWC) and the consolidated-undrained triaxial test (CU) of unsaturated soil under natural conditions results, studied wet-dry cycle Qianjiangping landslide conditions slippery soil strength and deformation characteristics, reveals the instability mechanism of Qianjiangping landslide.

Phosphogypsum-fly ash-lime solidified mixtures can form strength in a short time for the mixture, but excessive phosphogypsum will result in the expansion and the loss of strength . This technical note summarizes strength-forming mechanism of phosphogypsum mixtures for subbase constructions. The experimental results indicate that excessive phosphogypsum resulted in the expansion. The loss of strength and the optimum grading of phosphogypsum and fly ash is 1 to 1. The program of reusing phosphogypsum mixtures is discussed based on it.

The creep deformation of rockfill is a key problem in design of high earth rockfill dam, but it is not solved well so far. Using the large-scale high pressure triaxial creep apparatus, a number of tests on rockfill are carried out. The triaxial creep test method, the jumping-off point of creep and the creep deformation steady criteria are discussed ,and at the same time the jumping-off point of creep and the creep deformation steady criteria are suggested. The test results show that the creep deformation for rockfill depend on confining pressure and stress level, especially in the high confining pressure and high stress level, the steady is slow in evidence. The relationship between creep deformation and time is linear in the log-log plot and the laws of the creep deformation are similar in different stress conditions.

Freezing tests in two different kinds of modes in the case of open system on 1D soil sample made of Tibetan silty clay are carried out, and the evolvement characteristics of the sample’s frost heave、temperature gradient field are obtained. Then according to the self-made programme based on the heat and moisture coupled frost heave model, aforementioned tests are simulated, and the result of simulation is quite consistent with the test result. Our research shows that frozen soil can make more frost heave easily under stepwise freezing modes. Our analysis makes it clear that the temperature gradient in frozen fringe with stepwise freezing mode is greater than that with continuous freezing mode.

Triaxial compressive tests on limestone are conducted with a variety of confining pressures that range from 2MPa to 10MPa. This observation causes us to conclude that the deformation of limestone can be divided into four stages and the wreck is brittle cutting, The peak and stub intensity value increase with the confining pressure adding up, but the strain of the stress peak has no relativity to the confining pressure. By the redressing analysis, the formula of relation between intensity parameters is produced.

An introduction to a new apparatus, which can measure the individual particle strength of sand soils, is made. The strength of individual particles with various sized calcareous sand taken from South China Sea are also measured in this paper. It is shown that the new apparatus is suitable to measure the individual particle strength of sand soils with high accuracy and reliability.

The mean total mean stress, deviator stress and Lode’s angle are the three major factors affecting the generation of pore water pressure. The study of the pore water pressure coefficients is summarized. Within the classic elastoplastic theory, new pore water pressure coefficients are deduced based on the Unified Hardening Model, to which the transformed stress tensor is applied. The new coefficients can reflect the above-mentioned effects of the three factors on the pore water generation.

The modified Cambridge model is one of the most popular elastoplastic models for soil, but it can not simulate the soil constitutive behavior during large stress reversals and the stress induced anisotropy as well. In this paper, the rotational kinematic hardening theory is incorporated into modified Cambridge model, and the rotational hardening mechanism of ellipse yield surface is presented. Then, a new modified Cambridge model is extended from isotropic to rotational kinematic hardening in a simple manner which avoids the introduction of complicated rules and new materials parameters. The new model not only preserves the behavior of the isotropic hardening model under monotonic loading conditions, but also can reflects the soil constitutive behavior during large stress reversals and the stress induced anisotropy, and its validation is given at last.

The basic principle of equivalent additional stress method is that only soil skeleton is concerned while the reinforcing effect is considered to be equivalent additional stress acting on the soil skeleton in the direction reinforcement being bedded. This method is fit for fiber reinforced soil, soil nailing wall and soil reinforced with layered reinforcements, etc. It can not only remove interface element for the method dealing with soil and reinforcement separately, but also avoid determining the composite constitutive equation of the reinforced soil. However, iteration is necessary for the conventional equivalent additional stress method, which makes it difficult in writing FEM program. In this paper, a modified method is put forward to deal with this problem. An additional matrix is calculated and added to the elastic matrix or elastoplastic matrix of soil, the method can be employed directly without iteration. The modified method is easy for writing FEM program and helpful for extending the application of equivalent additional stress method.

The seepage rules of coarse-grained soil are very complicated. The present rational equations just consider some simple facts, therefore it is hard to identify accurate seepage factors. In this article, the coarse-grained soil obtained in Three Gorges Reservoir area is used to calculate the seepage factor of different graduation through the experiment, which is predicted through the powerful nonlinear and dynamic dealing capacity of the neurotic network. As a result, the influence of different graduation of the coarse-grained soil is taken into account. Through a comparison between the prediction from neurotic network and the experimental results, and the former can be used to predict the seepage factor of coarse-grained soil and this method can reflect the influence of different graduations.

A hydro-thermo-mechanical model is presented for concrete at elevated temperature. Three phases of continuum were adopted in this model: gaseous mixture of water vapor and dry air, liquid water, and solid skeleton of concrete. Mass conservation equations, linear momentum conservation equation, and energy conservation equation are derived on the basis of the macroscopic Navier-Stokes equations for a general continuum, along with assumptions made for the purpose of simplification. Mathematical relationships between selected primary variables and secondary variables are given with existing data from references. Specifications of the constitutive relations are made for the kinetic variables and their conjugate forces. Consequently a set of governing partial differential equations are obtained.

A general relation, expressing changes in averages of slope displacements at different time scales as wavelet transform coefficients corresponding to those scales, is presented through analyzing the integral description of the difference between averages of measured displacement data over two adjacent time intervals in comparison with the wavelet transform equation by using Harr wavelet mother function. On basis of this relation, a method to carry out the multi-scale analysis of displacement evolution for slopes is proposed in which changes in averages of slope displacements over two adjacent time intervals at different time scales can be determined by means of wavelet transform method. The multi-scale characteristics of displacement evolution for the new landslide in Wolongsi slope, the excavation of the permanent ship lock in the Three Gorges Project, and the construction of the intake in Geheyan Hydropower Station, respectively, are discussed by using the measured data of slope deformation. When the developing tendency of slope displacements is relatively regular, their characteristics evolving with time can be draw from the measured data at one time scale level. The influence of strong excavation disturbances up on slope deformation can be approximated by the raising line that links the end of support time interval at a given scale with the time point at which the displacement sharply changes.

Stress-induced anisotropy is one of very important characters of soil and also key difference from metal material, which exist in many geotechnical projects. The traditional soil’s constitutive models, which are developed with the isotropic assumption, cannot describe such stress strain relationship. Based on a series of true-triaxial tests under complex stress states, basic anisotropic deformation mechanism and mechanical characteristics of soil are discovered, which will supply enough data for the establishment of anisotropy constitutive model. By considering the stress-induced anisotropy under complex stress states, new anisotropic elastic model and anisotropic plastic model may be developed., which can describe the stress-induced anisotropy.

The viscous debris flow has a very strong eroded ability. It can erode a large amount of loose matters by its constantly erosion or lateral erosion and take them away during its flowing process, which makes it become more dangerous. According to the debris flow constitutive model and soil shear strength theory, take the upper bound theorem used in limit analysis as measure, and under the condition of assuming the erosion surface as arc, the startup mechanism of corroding to the ditch is studied. Then the corresponding calculating formula and judging criteria are suggested. At last, the influence of some factors on the erosion start velocity, such as the gravity, the falling gradient, the strength of the soil and so on, is discussed intensively.

Based on two kinds of visco-elastic plastic damage constitutive equations according to “hypothesis of strain equivalence” and “hypothesis of complementary energy”, the principle of minimum dissipative energy is applied to visco-elastic plastic damage theory of solid materials. The nonlinear evolution equations of visco-plastic strain, damage variable and strengthening or softening parameter of damaged materials are presented. Visco-elastic plastic damage constitutive equations and three nonlinear evolution equations of damaged material, are considered and two different visco-elastic plastic damage models A and B of solid materials are established, and these two model are examined. Finally, the visco-elastic plastic dynamic damage problem of a concrete gravity dam due to earthquake load are analyzed by adopting visco-elastic plastic damage models A. Results show that this model can be used to analyze the dynamic damage of concrete gravity dam.

Considering rock mass is structure of made rock matrix and fracture, with research method of rock structure mechanics, based on the differences of micro-structure and random distribution of rock, the physice mechanical properties’ random non-homogeneity, the paper presents 3-D random non-homogeneous solid-flow-heat coupled mathematics model and FEM, analyzing carefully features of random non-homogeneous solid-flow-heat coupled mathematics mode. This model is development of homogeneous the solid-flow-heat coupled mathematics mode, this paper offers the foundation and methods for the study of rock hot cracking.

The deformation of clay is controlled by the contact between grains which is classified as perfect contact and sliding contact in this paper. In the elastic deformation phase, the contact between grains is regarded as perfect contact. With the increase in shear stress, there are gradual conversions from perfect contacts to sliding contacts which are viewed as damages in this paper. Based on Mohr-Coulomb law, a calculation method for the damage ratio is given according to the relative distance of the stress point to the initial damage line and failure line. On this basis, a damage constitutive model is proposed. The model properties can be simply obtained through the conventional triaxial compression test. Consolidated-undrained test results indicate that the model is capable of predicting the shear deformation behavior of clay under various conditions, including varying hydrostatic stresses and stress paths.

The shear stress distribution analytical model of the grouted rock bolt in uniformly deformed tunnel wall rock mass has been developed according to the anchoring solid mass’s forcing situation and the M－C yielding criterion of the interface between anchoring solid mass and wall rock mass. And according to the interaction between anchoring solid mass and wall rock mass of tunneling, the interaction model and general solution to the shear stress of the rock bolt without decoupling at the bolt interface have been developed. For rock bolts installed in uniformly deformed rock, the loading process of the bolts due to rock deformation is taken into account in developing the model. Model simulations confirm the previous findings that a bolt in situ has a pick-up length, an anchor length and neutral point.

The penalized Heaviside function associated with the discrete variational inequality formulation of Signorini type is improved, and an adaptive form of the penalized Heaviside function is suggested to further improve numerical stability and overcome mesh dependence of the variational inequality approach of Signorini type. The suggested approach is applied to seepage analysis of the dam site of Gongming Reservoir, Shenzhen, and the effectiveness of the variational inequality approach of Signorini type for complex three-dimensional seepage problems with strong nonlinearity is validated.

The effect of strip surcharge on the inclination of sliding plane of soils behind retaining wall is taken into account. New formulas of active earth pressure due to strip surcharge are presented based on Coulomb’s theory. When the surcharge is zero, the formulae are the same as Coulomb’s theory. If the strip surcharge is cut by the sliding plane of soils, it is shown that the obliquity of sliding plane of soils behind the wall is not only related to the angle of internal friction of soil, the angle of wall friction and the inclination of ground, but also to the magnitude of surcharge and the distance of the surcharge from the wall. It is also shown that the farther the surcharge from the wall, the smaller the coefficient of active earth pressure. The bigger the magnitude of strip surcharge, the bigger the coefficient of active earth pressure.

The discrete fracture network model is confined in the application of rock mass seepage because of the numerous discontinuities in engineering rock mass. This makes investigators search mature equivalent continuum medium model in theory substitute the discrete fracture network model. Thus the research on porous medium hydraulic equivalence of fracture rock mass is necessary. Based on plenty of field measured fracture data, a statistical analysis about fracture density, azimuth, size, continuity, jaw opening is made, the random model of discrete fracture network is established on Enhanced Baecher model. The Monte Carlo random simulation is used in fracture network random simulation, thus the three-dimensional discrete fracture network figure of different dimension is obtained. On the basis of the three-dimensional discrete fracture network the REV is calculated, the equivalent continuum medium model can be analytical rock mass seepage.

A large number of experiments have proved that fluid flow and stress characteristics are different from each other under loading and unloading effect state. In recent years, research on hydro-mechanical coupling of fractured rock mass under loading conditions has advanced greatly, but corresponding research on hydro-mechanical coupling considering unloading effect has still been in an early stage. And then, constitutive relationship including seepage parameters between unloading stress and strain is constructed based on existing fracture deformation curve, meanwhile, fluid flow and stress characteristic of an example under different operation modes is analyzed according to coupling theory mentioned above. The calculation results illuminated as follows: stress field changing make fluid flow coefficient close to slope surface increasing and saturated line falling so as to augment slope stability when taking consideration of unloading effect; and displacement and stress field vary greatly after considering seepage effect, but discrepancy of both characteristic distribution between considering coupling and discarding coupling was knee-high to a duck; and the final conclusion is that stress field changing influencing fluid flow field is larger than that fluid flow changing influencing displacement and stress field.

After simply partitioning a complicated block, then based on the basic theory of block and the limit equilibrium principle of rigid body, a new method of analyzing a three-dimensional block with multi-constructional surfaces is studied and an applicable program for analyzing the three-dimensional limit stability are developed, both of which have been successfully applied in several projects, such as the high side slope on the right abutment of the dam of Longtan Hydropower Project.

It is really a challenging problem always going with geotechnical engineering to transfer the rock mechanics parameters to the engineering rockmass mechanical parameters. On the base of the in-situ investigation, field engineering coring and laboratory experiment, research is done into the rockmass mechnics parameters by combining with RMR system and BQ system，the comprehensive evaluation results have provided the basic data for the design and construction of the slope engineering. The engineering practice has benefited technically and economically from the theoretical results. Our research has an important theoretical significance to direct the practice in similar projects.

Because of complexity about property of unsaturated soil, getting correlative strength parameters needed high and extract equipment, the difficulty is big so that its application is limited. Based on an analysis of strength theory of unsaturated soil, CD test of clay about different combination of water content and dry density is carried out with normal three-axis test. According to the theory of effective strength of soil, the effective strength of clay about water content and dry density is discussed, thus functions of total strength indexes are established that the effect of water content(saturation) and dry density can be considered. Study shows that strength of clay has close connection with water content and dry density. Moreover, the relation between cohesion, internal friction angle and water content(saturation) is conic, the relation between cohesion and dry density is linear, and the mutual effect of the both can be expressed by multiplication. Our research can be used as a reference application of project.

After careful analyses of the popular Monte Carlo method and geometric method in reliability analysis, the misuse of Monte Carlo method with several non-uniform distribution random variables is pointed out. As a result, a correct procedure sampling procedure of Monte Carlo method is presented. Meanwhile, in order to satisfy the needs of practice in reliability analysis, an extended geometrical optimized method(EGOM) is proposed, its procedure under conditions of correlation and non-normal distribution variable is also presented. Furthermore, several examples from others’ reliability analysis practice with the proposed EGOM prove its correctness and effectiveness.

Aiming at the complexity and fuzziness of loess collapsible degree, an evaluated model of loess collapsibility is established with the application of the theory of fuzzy measure. The evaluation index of the model is coefficient of collapsibility, and the factors are natural specific gravity, dry bulk density, moisture, void ratio and plasticity coefficient. The point estimates of the evaluation index and measure function can be obtained by training a set of learning samples. Then the classification of the distinguished samples can be got. The practice showed that, the evaluation model functions well with high prediction accuracy and can be applied to practical engineering.

The visco-elastic-plasticity model is often used to solve soil creep problems. The key point is how to determine the parameters for the complex model. These parameters have to be obtained with the laboratory tests. However, the soil creep process may last for several decades or even hundreds of years, while the laboratory tests can not be carried out for more than several months at most. Therefore, it is very important to estimate the reasonable parameters for FE analysis by extrapolating the laboratory test results. In this paper, a statistical method is presented to give an estimation of the parameters for the visco-elastic-plasticity mode. The estimated parameters have been successfully used to assess the creep tendency of Tianjin Harbor and several other projects in which the creep effect is concerned.

Based on CT images and utilizing analysis of physical characteristic value and naked eye observational estimate respectively, the time of damage appeared in the rock or soil is estimated so as to prove the limits of simple observation by eye. Then, using contour method determines the location of damage and judges its extending direction. Through analyzing curve of maximum and minimum of CT number and loading within specimen, the subarea thresholds of non-damage part, damage part and fracture part are determined. Moreover, binary images of each part are obtained under these thresholds. Finally, shape, geometry and physical characteristic value of these binary images are measured quantitatively.

Based on effective stress theory, combining elastoplasticity geometry equation,constitutive equations and balance equation, stress field equation is established. By mass conservation equation of hydromechanics seepage flow field equation of coal bed gas, water and coal rock soild grain is established. These equations, secondary equations and fix solution condition form mathematical model of coal bed gas-water fluid soild coupling under stress. Using predigesting model to analyze single phase fluid soild coupling, distributing curve of pressure dynamic is obtained, effect of pressure distributing in coupling and non-coupling,so privide theory base for analysis of coal bed gas fluid solid coupling is analyzed.

A new analytical model for split-set rock bolt under pull-out force has been developed. Research shows that slips may occur first at the loading point under pull-out force when the applied load is large enough. The length of slip segment increases with an increase in the applied load, and finally the length of slip zone arrives at the length of rock bolt. Based on the conservation of energy, formulae of radial forces acting on the surrounding rock mass induced by split-set rock bolt are obtained. On the basis of nonlocal friction model, the distribution of shear stress on the interface of split-set rock bolt is determined. Through the parametric study of an illustrative case, effects of the rock bolt’s diameter on the distribution of shear stress is studied, the relationship between the ultimate pull-out strength and rock bolt’s length is also obtained. It is shown that the present analytical model is in good agreement with the experiment results.

Because of the special structure characteristic, the deformation and strength of loess are affected by water and load together, so the research of loess mechanics must take account of water and load effect together. In this paper based on the theory of thermodynamics and continuum damage mechanics and the energy conversion of loess in load and moistening, the damage variable, load damage and moistening damage of loess and their relations are put forward. The basic framework of the elasto-plastic damage models of loess which are made up of plastic, load damage and moistening damage are also put forward. This is a new method to put forward the structure model of loess.

The relationship between thermal conductivity of geotechnical material and its porosity is simulated by using finite element method. The solid matrix and pore are generated randomly according to material porosity, and material parameters and element properties are changed by ANSYS parameter design language. The effective thermal conductivity is computed according to thermal flux through some section computed by FEM and Fourier heat transform low. The investigation shows that the effective thermal conductivity decreases with increasing porosity, and the gradient increment of effective thermal conductivity with respect to porosity ratio may decrease obviously while the porosity reaches percolation critical value, and the thermal conductivity characteristics of geotechnical materials pose the percolation transform properties that are the same as seepage in porous medium.

The Plate Loading Test is the most used way to acquired the bearing capacity of foundation in the world and it’s widely used in checking the results of the treatment foundation, but it also has some shortcomings, including size effects, high expense, time cost and so on. In this paper the FEM by step-loading was used to analyze the process of the Plate Loading Test and to obtain the bearing capacity of foundation. A lot of valuable results was got.

Affected by geology and natural weather of dry and wet cycles, many slopes of expansive soil lead to the development of the fissures and finally became a block system. To take the slope of expansive soil as a block system in which soil blocks have constitutive relation of non-saturated soil, there are frictional and expansive forces between the blocks, and there is a feature of towed slide and effect of time and space. A new method of discontinues deformation analysis are formed for the slope stability analysis of the expansive soil. This method is used to analyze the stability analysis of some slopes of the expansive soil in a highway, and very good results are available.

The elastic half-space problem vertically loaded by internal uniformly distributed circular force is the fundamental theoretical problem of piled foundation engineering. The general solutions of displacement and stress in integral form were derived with Bessel integral transform method. The half-space problem was separated into two parts according to the plane in which the force is loaded. By properly introducing boundary conditions and continuity conditions at the interface between two parts, the theoretical solutions for displacement and stress of the elastic half-space due to internal uniformly distributed vertical loading were given. The formulae of average vertical displacement and vertical normal stress in the loaded area at different depth were put forward for convenience. The numerical results show that the method presented in this paper gives the right solution.

Because most project accidents can not be explained by constitutive models in which the localization is not taken into consideration, now the study of localization and the formation of shear band in soil have become an important research field in soil mechanics. Numerical simulation is an important method researching into the formation of shear bands. In this paper, research is done on the condition of the formation of shear bands. Then the formation of shear band in different situations is analyzed by considering the non-homogeneity of soil and introducing weak and strong elements.

For research on the ultimate bearing capacity of shallow foundation on slope, it uses the finite element analysis with the multiple zero-thickness interface elements which considers the Coulomb’s failure criterion. The influence factors of ultimate bearing capacity, slope angle and distance from the slope margin are particularly studied. The minimum upper bound of bearing capacity and the behavior of progressive failure are also investigated in this research. The ultimate bearing capacity calculated in this study is taken account that shallow foundation is seated on (1) the semi-infinities ground, (2) the slope margin and (3) the distance from the slope margin. The results obtained shown that the ultimate bearing capacity of shallow foundation decreases as the values of influence factors decreases. In other words, while the shallow foundation seated on the slope margin during the vertical slope excavation, the value calculated of ultimate bearing capacity decreases about 50 % less than that obtained by the case of semi-infinities ground.

In order to study the mechanism of how deeply-buried piles reinforce slope, five groups of large scale physical model tests were conducted in the lab of Chinese Northwest Railway Academic of Science. In the experiments, pressure endured by deeply-buried pile in different places is not the same, which indicates that the experiment can’t be simplified to plane strain problem. Finally, several groups of model tests are simulated by three-dimensional finite element of elastic-plasticity. The result is almost identical to the experimental data, this justifies the application of three-dimensional fem method to design deeply-buried pile.

Contact element is used to simulate the nonlinear behavior of interaction of diaphragm wall and base. Duncan-Chang E-B criterion is used as constitutions relation of base and dam to represent nonlinear and inelastic characteristics. FEM is used to calculate the stress and deform ation of dam, base and diaphragm wall. The result shows that the stress and strain of dam depend on the selection of dam. The characteristic of diaphragm wall also affects the stress and strain of dam in some regions. The stiffness of diaphragm wall is a key factor in the stress and strain in dam and diaphragm wall. If the stiffness of wall is large, the vertical displace is affected obviously. And the danger location is at the bottom of the diaphragm wall. Besides, the ability of adapting to deformation is high. But the displacement is large. The danger location is at the bottom of dam.

Stability of cracked expansive soil slopes subjected to rainfall infiltration is closely related to seepage distribution. The impact of accumulated water depth on seepage is numerically analyzed. The results show that the impact of accumulated water depth on seepage distribution is very small and the assumption that accumulated water depth is zero can be accepted in seepage analysis. Based on different dimension of cracks and their different permeability of expansive soils, a new method of seepage analysis subjected to rainfall infiltration considering cracks system is presented, which shows that cracking behavior not only has a great effect on seepage distribution, but also much better simulates seepage distribution change with time than before. And the results obtained from engineering cases can reasonably explain the mechanics of shallow landslide of expansive soil slopes.

A significant anisotropy is found in the permeability coefficient of the rockfill of a concrete-faced rockfill dam. A 2-D and 3-D fixed-mesh FEM seepage analysis is made on the concrete-faced rockfill dam of the Jishixia Hydropower Project under both normal conditions and abnormal conditions where a crack occurs in the slab. The FEM meshes are obtained according to the designed schemes and topography of the dam. The seepage field and seepage amount of the dam are calculated. The effect of the crack’s location on the seepage is also discussed. The calculation results show that the dam is stable in the seepage aspect under the normal design water level. The position of the crack has a significant effect on the seepage field and seepage amount of the dam.

Based on the model of 3D porous medium, the fracture as a very important permeability channel is taken into account in the theoretical research on percolation of medium, the research methods of percolation in 3D porous and fractured double-medium is put forward, and the percolation model of 3D porous and fractured double-medium are established. The model applies to more fields, such as coal bed, rock mass. Based on VC++6.0, the software of 3D is developed, the percolation and the percolation law of 3D porous and fractured double-medium are simulated. The results indicate that fracture in the model increases the value of percolation probability observably. It makes the percolation law of double-medium differ from the law of porous medium. The natural phenomena of percolation transition happens surely with the increase in porosity, fracture fractal dimension and fracture number distribution initial value.

A preliminary study is made of the h-adaptive refinement scheme for the Natural Element Method(NEM). The solution error is estimated by using the ZZ error estimator which is based on the recovery stress filed acquired through the MLS/NNI stress recovery scheme according to the character of the NEM. Then new nodes are inserted automatically according to the error distribution information acquired. With the process of the adaptive analysis, the solution error reduced and the distribution of the error tend to be uniform. In numerical analysis, there is mainly two sources of error, namely the interpolation error and integration error, with the increase in nodes, the size of Delaunay triangle decreases and the stress tend to be linear, so the interpolation error and integration error decreases accordingly. In the process of adaptive analysis, solution errors can be reduced and the accuracy improved. The Voronoi tessellation is needed in the NEM analysis, the refinement scheme presented is just involved in the local adjustment of the Delaunay Tessellation. The implementation of adaptive process is effective and efficient. Numerical examples show that the adaptive scheme is successful and NEM is especially suitable for h-adaptive analysis.

Solid element is often used to simulate soil and rock in geotechnical engineering. Other structures such as pile, cut-off wall and concrete panel are also often simulated with solid element when then are embedded in soils. Internal force and bending moment are important for design of these structures, so it is necessary to calculate bending moment with stress and displacement obtained by finite element method(FEM). This problem is studied by analyzing a cantilever beam. It shows that enough elements are necessary when bending moment is calculated with stress, whereas oscillation occurs and leads to unreliable results when bending moment is calculated with displacement. Shear locking and its influence is also investigated herein.

The extended finite element method(XFEM) is a new numerical method of modeling strong as well as weak discontinuities within a standard finite element framework. The principle consists in enriching the basis of the classical finite element method by some singular functions around the crack tip and by a step function along the crack line to take into account the discontinuity of the displacement field across the crack. This enrichment strategy allows the use of a mesh independent of the discontinuity geometry. Numerical aspects of the XFEM are studied, including the representing of interface and the determination of enriched node and enriched model by level set method by level set method, the selection of enriched domain at the crack tip, the determination of quadrature domain for J integration and the quadrature scheme.

Many factors, such as water-level, velocity and sediment charge of river flow, affect the erosion of riverbanks. Moreover, the strong seepage force may result in a higher riverbank scour rate. The formula for riverbank scour rate under seepage force is developed based on an of analysis of forces acting on sediment particles and the experimental data in a rectangle flume by Wang. An example is given to show the application of the formula to riverbank scour rate. It is expected that the formula for bank scour rate can be used to analyze the changing process of riverbank landform and to forecast bank collapse.

This paper reviews several bolt numerical simulating methods which are being used at present, and does a special research to the theory and applicability of the three-dimensional bolt elements which takes the tangential mechanics properties of the grout into account. By means of the FEM and the models mentioned，the program is developed to simulate the bolt and the structure. Through an example, it make sspecial research on bolt’s mechanical characteristics. The calculations illustrate the capabilities of the elements.

An analytical solution for shear distribution of anchor under pull load is present by considering the progressive failure of anchor-soil interface, based on Mindlin solution of force at a point in the interior of a semi-infinite solid. Then an analytical program is developed accordingly, and the flow chart of program is also presented. The results of analytical solution and the field measurements all show that peak value of resistance at the anchor-soil interface transfers to the distal end of the bonded length as the applied load increases. Further, the effect of soil elastic modulus and anchor diameter on shear distribution between anchor and soil is studied by using this analytical model. The result shows that greater soil elastic modulus leads to greater peak shear magnitude under the same load while greater anchor diameter leads to smaller peak shear magnitude.

Considering the behaviors of strength reduction and volume dilatancy of rock materials, the approximate analytical solutions to calculating the extent of the plastic zone, stress field and displacement field in rock masses of circular tunnels are proposed. The elastic-softening-residual plastic triple linear stress-strain model and the Mohr-Coulumb failure criterion are involved. The analytical solutions are valid when the plastic zone is comparatively large and the lateral pressure coefficients 1≤λ<3. These solutions are very close to the results calculated by the finite element method, which can be used for the simple elastoplastic analysis of the circular openings instead of the finite element method.

Advances in research on semi-analytical method in geotechnical engineering are summarized. Finite layer method, analytical calculation method, isometric transformation method, generalized shear displacement method, and generalized load transfer method are introduced in detail. Research indicates that semi-analytical method will be widely used in computation.

By using the Duncan E-B constitutive model, the concrete-faced rockfill dam of Taoshui Reservoir project is calculated under the construction stage and impounding stage respectively. The deformation and stress distribution of rockfill and concrete face are obtained, which are proved to be reasonable compared with the other projects in China.The results are valuable for the design and construction of the similar dams.

Based on theory of visco-elasticity and heat transfer, the stress of reflective crack under the thermal variation is studied by finite element simulation. The influence of variation stress fields and road design parameters on the thermal stress of the crack is discussed. It can be show that the surface stress near the crack is larger than the tensile strength of the asphalt, which leads to the crack propagation. The scheme of crack prevention, which uses the polyfibre geogrid, is put forward. Numerical results show that the validity of the present scheme.

A comparison between the Lagrangian and Eulerian kernels used in meshfree approximation is illustrated. Then with the Lagrangian approximation an accelerated meshfree formulation for dynamic as well as static analysis of slope failure at finite deformation range is presented. The present formulation employs the stabilized conforming nodal integration (SCNI) to ensure the spatial stability and improve computational efficiency. The degradation of slope materials is characterized by the coupled elasto-plastic damage model via the rate form, where the Druker-Prager yield function and isotropic strain-based damage criterion are used. The non-local nature of meshfree approximation and SCNI scheme enables the current approach to effectively simulate the shear band arising from strain localization during slope failure process. Finally a numerical example is given to demonstrate the proposed method.

Smooth blasting is generally used to excavate rock anchor beam at the underground power station, its aim is to better quality and smaller crushed region. However, the blasting of the main hole damages the smooth layer to a certain extent to reduce the mechanical parameters of rock mass. The more powder is charged each hole and rock mass is over excavation or generate lots of cracks without considering this effect of damage. The 2D dimension elastic-plastic model of rock mass is adopted and the smooth blasting procedures with and without this damage are simulated in the dynamic finite program. According to the results of comparison of maximum effective stresses of different distance of 2 kinds of models, when the effect of this damage is considered, the interval of holes and the burden can be widened under the same condition. The model considering damage is proved by in-site blasting experiment well.

According to the distribution characteristics of in-situ stresses measured in the fault-block G around complex faults, in-situ stress field is simulated and estimated by establishing numerical model suitable for geological structure of the block G and applying the COFEM method(constrained optimization finite element method) based on the FEM method and the theory of constrained optimization. Simulating results fit with the distribution characteristics of the measurements. In addition, the influence of complex faults on regional in-situ stresses is analyzed by comparing the in-situ measurements with numerical results. It is shown that the distribution of in-situ stresses around faults is mainly affected by its near faults, and depends mainly on the scale of the fault and the distance from the near fault. Because of the influence of the faults, the distribution of in-situ stresses around faults is complicated, especially the terminal portion of faults, the distribution of in-situ stresses field can not be generated by some discrete measuring points. Three-dimensional numerical simulation is very important for us to analyze and estimate the in-situ stresses field.

The nonlinear flowing rule in low permeability reservoirs can be described entirely with the nonlinear mathematical model. The theoretical calculation method of flow pattern distribution is proposed. Flow pattern distribution under the influence of injection-production pressure, injection-production well spacing and formation permeability in low permeability reservoirs is analyzed in this paper. The model proposed here also describes the pressure distribution characteristics of fluid flow in extra-low velocity in low permeability reservoirs, which corrects former misunderstandings of the characteristics.

There are two types of seepage media in the fractured rock mass, the main seepage part is the seepages through the discontinuities. It is very difficult to simulate the seepage characteristics of the intersected fractures in the network like in the fractured rock mass according to the conventional method. Therefore, the basic idea to simulate the seepage law of the intersected fractures is to get the two dimensional fractures network from three-dimensional random discontinuities numerical network model, applying meshless method based on the least-squares procedure which is moving approximately least-squares procedure, the test calculation is carried out by the program which is self written, a satisfying result is simulated, the feasibility of simulating the seepage law of intersected fractures by meshless method is proved.

In order to keep the safety of the earth dam, the seepage characters of the earth dam should be analyzed in the hydraulic engineering and the free surface should be determined firstly. According to Darcy’s law, seepage constitutive equations, water head and flux boundary condition, a model is established for the seepage in the in homogeneous earth dam on imperviousness groundwork. By the Geoslope software, the free surface of the earth dam is calculated using the finite element method, and the change of the free surface is analyzed when the permeability of the earth dam is changing. At last, the numerical simulation of the free surface is verified by an analytical solution.

The groundwater problem is a key issue which affects stability of the surrounding rock in tunnel engineering. A method is proposed to depict mechanical and hydraulic behavior of the tunnel ground by tunnel excavation. Based on structure of rock mass and concept of representative element volume(REV), the methods of hydromechanical coupling model is proposed. Relevant methods of establishing tunnel excavation hydromechanical coupling mathematical models are proposed. The analysis results indicate the influence boundary of stress disturbed is smaller than that of seepage disturbed boundary. The seepage forces caused seepage increase stresses and deformations in tunnel ground. According to the interaction principle between ground and support structure, the seepage effects should be considered in tunnel support structure design.

Based on the statistic theory, seepage coefficient of rock and soil is considered as random variable. Therefore rock and soil can be assumed to be mixture with different seepage coefficients of isotropic media, according to the probability distribution of seepage coefficient. The contribution of rock and soil with different seepage coefficient to seepage field are determined by their probability. After determination seepage coefficient of rock and soil, water head of region and flux of section can be obtained by solution seepage equations with different seepage coefficients. As a result, the final water head of region and flux of section are weighted by the probability distribution of seepage coefficient. This method is proved by engineering example with fewer errors than FEM, so it can be another way used to analyze seepage.

The Computational Fluid Dynamics (CFD) technology [1] is used to numerically simulate the Bingham viscous debris flow which is a kind of debris flow. The software used in this study is CFX which belongs to the current CFD software, the 3D landform of debris flow cleuch and blocking dam model is created by the CAD software of Unigraphics (UG) and AutoCAD, the velocity field of debris flow and dimension and distribution of debris flow fluid pressure on blocking dam are calculated by the computation.

Structure and support failures of tunnels are common problems for deep tunnels in high in-situ stress rock masses and they have more requirement on support designing. Based on the alteration of surrounding pressure and the strength of engineering rock mass, the mechanism of deformation and failure of surrounding rocks of the tunnel constructed in high in-situ stress rock masses is studied. According to rock character of a certain tunnel of Chongqing, the Mohr-Coulomb criterion with tension cut-off strain- softening model is adopted, a three-dimensional nonlinear simulation for it has been carried out. The distribution of plastic zones, tensile stress zones ,displacements and the progressive failure of the surrounding rock is analyzed , the failure law of the surrounding rock in high in-situ stress. For application in site ,the physical model results is used and the results agree with the numerical model.

When the conventional strength reduction finite element method is used to determine the plastic zone of slopes, the results obtained are not so accurate, the shape of plastic zone and the position of sliding surface can not be directly visualized. Using the method of local mesh refinement around the plastic zone, one can not only improve the accuracy of the safety factor calculated greatly but also solve the shape and position of sliding surface. For the specific problems of searching the sliding surface in the plastic zone, a plastic strain limit is presented as a mesh refinement criterion. The shape and position of the sliding surface and the safety factor is determined by local mesh refinement method. A lot of numerical computations are carried out, the results have shown that the criterion used is effective for determining the shape and position of the sliding surface, and the error of the safety factor between the computed value and the accurate value is only 0.2 %.

More attention is focused on the problem of tunneling passing across the adjacent pile foundation. On the basis of a study of the current research findings, the method and parameter determination of numerical simulating on pile foundation are discussed . A case history that the tunnel was constructed through the adjacent pile foundation in Beijing is simulated, and deformation characteristics of surrounding ground and neighboring piled foundations caused by tunnel excavation are analyzed. The research results can be served as a reference to predicting the influence on the surrounding environment by tunnel excavation.

The rock mass is a nonlinear and discontinuous medium. Considered from the modern engineering scale,there should be a much better understanding of its physico-mechanical properties. Comparing with it, numerical simulation is a much better tool to know it because its merits of less time, low cost, simple manipulation. The basic situation of discrete element method which applies more extensively and develops more maturely among the discontinuous medium numerical methods is introduced, the several typical problems are expounded in detail, the researching progress of discrete element method is introduced in detail, and its relevant applications are also introduced, then the summaries are generalized, several developmental directions for the future are discussed.

The four seepage tunnels in Jinping II Hydropower Station are buried in the hard brittle rockmass. The complex geological condition including high stress induced by great depth and high seepage pressure will bring about many engineering problems, especially the long term stability problem. In order to reflect the character of the visco-plastic deformation, the combinative models of cohesion weakening-friction strengthening model and the visco-elastic model are introduced in this study. And based on the in-situ displacement monitoring data, the visco-elasto-plastic model and its parameters are obtained by the intelligent method based on GP and PSO methods. The rheological mechanic characters of the surrounding rockmass in the seepage tunnels are simulated by using FLAC3D. At the same time, this program can also simulate the mechanism between the sprayed concrete, rock bolts and rockmass and the coupling effect of fluid and solid under the high seepage pressures on the structures. Through the analysis of the calculated results, the long term stability of the tunnels is estimated by using the integrating method of multi-index including displacement, displacement velocity, stress, failure approach index and the internal force in the support structures and soon. The results are of importance to the design and construction of this project.

The construction of underground project or the underground tunnel will influence the subsiding of adjacent building on the earth surface. One urban underground tunnel is adjacent to a high-rise building called Shuijingchengbao. By using three methods that are qualitative analysis of engineering geologic, experience analogism of adjacent similar engineering constructions and 3D finite element method (FEM), the interaction and influence between the tunnel and the adjacent structure was synthetically analyzed and evaluated. The result indicates that the structure’s building has neglectable disturbance to the displacement and stress of underground tunnel, the maximal vertical displacement of tunnel roof is only 1.15mm and the change of plastic zone is tiny. Hence, it can be justified that the building of the engineering is unlikely to influence the safety and stability of surrounding rock of the tunnel without abnormality construction and exceptional engineering-geology. It can offer a theoretical reference to the construction of the underground engineering.

Recently many problems such as surrounding rock collapse, large-area settlement of ground surface etc have happened during soft rock and shallow buried tunnel construction of express highway. The stratum condition of a shallow buried zone of Guangfu Tunnel is very complex. The section is large and the lithology is weak. The action of conformation has much influence on the shallow buried zone. And its top length is very thin. It is very easy to cause cave-in collapse and fall of ground. In order to ensure the construction safety of shallow buried zone tunnels and reduce the stratum settlement and surrounding rock deformation caused by the excavation of tunnels, four construction projects are simulated by FLAC3D as much full section method, shot shoulder method, unilateral pilot tunnel method and double pilot tunnel method. The variation feature of ground surface settlement, surrounding rock circumjacent displacement and plastic zone during the four excavation projects are analyzed. These four construction projects are computed with finite element method. Some valuable conclusions are drawn: (1) the double pilot tunnel method may produce fewer vertical displacements and horizontal convergence and its stabilization is better. (2) the plastic zone radius for double pilot tunnel method is least. (3) it is the most reasonable that double pilot tunnel method is adopted in the shallow buried zone of Guangfu Tunne1.

A large arch-wall-shaped cross-section with 28 m in span and 22 m in height formed in the Jishixia waterpower project when the spillway tunnel and the diversion tunnel intersect in bad geologic site. The surrounding rocks are distributed in layers and a weak intercalation goes through the top of a cross-section. To verify the schemes of excavation and supports, 3D numerical simulation of excavating which tracks construction process is used to study the stresse and deformation distribution and the stability of the surrounding rocks. At the same time, the weak intercalation is taken into consideration. The results may have better reference values for similar projects in the future.

Performance function of lining structure reliability is established according to “action-reaction” model. Based on the statistical characteristics of physical property obtained by exploration of No.4, No.5 and No.10 line of Beijing Subway, the structural reliability of Beijing metro tunnel is analyzed by using Monte-Carlo method. The effects of primary support and lining under the condition of natural environment are discussed, the results consider that lining bear the whole loads during the operation and primary support only improve the work environment of lining. The elastic resisting coefficient around the lining should be increased, which can not only simplify calculation, but also meet the working situation of lining structure.

Middle wall is an important structure of a double-arch tunnel. To prevent harmful influence by unsymmetrical pressure on middle-wall has become the key problem during double-arch tunnel construction because of its complicated stress and deformation rule. Based on the construction of eccentrically compressed entrance of Fuxi highway double-arch tunnel with heavily jointed soft rock mass, the deformation and internal stress distribution behaviors of the middle wall is analyzed by the three-dimensional numerical simulation in the course of construction. It can be concluded from the result that the top of middle wall moved towards shallow side effected by partial load induced by terrain, and the middle wall also moved backwards and forwards with excavation of left and right tunnel differently. If the top clearance of middle wall is not filled immediately, the displacement and internal stress state of middle wall can be improved effectively. According to the conclusions above some suggestions are made for construction of Fuxi tunnel.

The uncertain problem in engineering can be solved by using interval, probabilistic or fuzzy theories. Interval analysis method is used to simulate the uncertainty in excavation and shoring of underground tunnels. By representing the uncertain parameters as interval numbers, the governed equations of structural system are obtained by means of the finite element method. These equations are complicated nonlinear interval equations which comprise uncertain geometric parameters. There are two optimization models which are discussed in this paper. Taking all the interval numbers in the equations as optimal design variables and representing the lower and upper bounds of each interval number as the boundary constrain of the variable respectively, the maximum and minimum of response components such as displacements and stresses are achieved by using the genetic and simulated annealing algorithms. The numerical results demonstrate the rationality and feasibility of the present method. As a contrast, the corresponding outputs of the boundary combination are analyzed.

Least square vector machines had the quickly solving speed and the excellent characteristics to describe the little samples, nonlinear and high dimensions problem. But the regression accuracy and generalization performance of this method depend on a proper setting of its parameters. So, an optimal selection approach of LSSVM was presented based on particle swarm optimization (PSO) algorithm. Then , the prediction on the thickness of the loosen zone around roadway is made by PSO-LSSVM model, and the results show that this model has the characteristic of quickly convergence speed and highly calculating precision .So, this model is reasonable and feasible.

Excavation controlling is a key technique in the process of large-section underground excavation, we can not only reduce costs of follow-up construction, but also enhance security if we control the underground excavation well. Selecting equipments of drilling holes, controlling the holes precision and refinement of charging are researched into and practiced in a large-scale underground powerhouse of Three Gorges project. Good results show that we can work additional 8.5 cm for the roofs and 5.3 cm for the sidewalls than standard in average, and control the extra-mining of cantilever crane beam in 2 cm, much lower than 20 cm which is the standard of criterion. The flatness of excavation is less than 10 cm, and the half holes rat of blasting is more than 95 %. A breakthrough in the controlling of forming quality is achieved, and it is highly value able in application. This paper will analyze and aggregate the specific process of controlling to provide example for similar projects.

Expressway tunnel of three driveways is often large-span tunnel with oblate cross-section because excavation span is large and ratio of height to span is small. This structure shape could make a bad influence on stability of surrounding rock and stress distribution of support system, so it is necessary to determine a reasonable tunneling scheme by academic analysis. The east Mao Mountain tunnel on the Ning-Chang Expressway in Jiangsu province is designed as a separate tunnel with uplink and downlink both having three driveways respectively. It is a typical shallow, large-span and oblate tunnel. The three dimensional numerical simulation using the FLAC3D software is conducted in this paper to model different excavation schemes, including CRD method proposed in pre-designing and partial bench cut method adopted in practice. The support parameters used in these two numerical models are both accordant with the data in design. The results show that partial bench cut method is feasible. A comparison between numerical results and observation data in practice is also conducted in the paper, which is more approved that the actual tunneling scheme is reasonable. The results of this study are expected to provide academic reference to design and construction for the similar engineering.

The idea of maintaining groundwater environmental balance is used to design the tunnel under high hydrostatic pressure. The parameters of tunnel water handling and the method of calculation of lining against water pressure are studied. In the end, the method of design is introduced with Lishuwan Tunnel as a example. The construction results show that the idea of groundwater environmental balance applied to design the tunnel under high hydrostatic pressure is rational,safe and effective for environmental protection,cost reduction,reduction of construction time.

Based on an analysis of engineering geology conditions of Pengshui Underground Plant, the 3-dimensional distinct element numerical model is established. The excavation and reinforced process of underground powerhouse of Pengshui project are analyzed by using 3DEC. The pattern of deformation, stresses state, distribution of plastic regions caused by excavation and influence factors of cavern surrounding rock are studied. Several conclusions are drawn: the whole stability of excavated and reinforced surrounding rock is good according to this paper’s calculation conditions; the displacement of upstream and downstream walls are about 15~35 mm under excavation and control of discontinuous combination; the mostly deformation of cavern walls are completed from excavated to subsequent 2~3 excavation steps. the excavation phases from 223.0 m to 201.0 m are important to stability of cavern walls; the characteristics of lay, interlay and continuous joints and the blocks location cut by discontinuous have significant effect on surrounding rock stability, but local shale deformation and geostress have little influence on the stability of cavern walls.

In the construction of tunnel through karst area due to the concealed caves which in the project could not be taken to safety and often made nonplused susceptible damage to the tunnel construction and that caused a great deal of potential safety problems and greater danger. Because the stability problem caused by mid and small-scale concealed karst cave when tunnel through karst areas is most common, The influence of different scale of crown concealed kast cave and the different distance between the tunnel and the crown concealed kast cave to rock stress, displacement and the internal forces of supporting structure were studied used numerical analytial test method, and the influence of the concealed cave on the tunnel plastic changes of the rock characteristics is also studied. Based on the numerical tests, the tunnel displacement changes inherent mechanism caused by top concealed are proposed. The study shows that within a certain scope of the existing large-scale top concealed cave will lead to increased displacement of the tunnel and the tunnel of rock stress will also increase. The research results of the karst area tunnel have a scientific and quantitative promotion to the design and construction of karst tunnel.

More and more attention has been focused on the study of the construction technology of highway tunnel considering environmental protection with the development of national economy and social progress. Based on the actual conditions of Lao-shan highway tunnel in Nanjing City, A new environment protection structure, called shed-tunnel structure, is developed. Synthesizing numerical analysis of five different structure style is made from three aspects, that is the bending moment, axial and shearing force, by finite element method software ANSYS. Finally we conclude that the shed-tunnel in the entirely arc style is the optimizing one.

Xiamen Subsea Tunnel is the first subsea road tunnel in China. The tunnel passes through the faultages of F1, F2, F3 and F4 where the rock mass is rotten and cracked. Rheological properties of this type of rock are remarkable. A series of triaxial compression rheological experiments are carried out. Experimental results, show that power law creep model can be used to simulate the primary creep and the secondary creep of the rock. Power law creep model and Drucker-Prager yielding criterion are coupled to simulate the nonlinear visco-elastic-plasticity of the rock. Numerical simulation is used to study the deformation properties of surrounding rock of Xiamen Subsea Tunnel and its ground characteristic curve.

In the process of construction of the tunnel underground cutting with shallow overburden，it is crucial to rationally delimit the size of digging length. If the size of digging length is too small, the construction time will be prolonged and temporary protection will increase. If the size is too large, the earth on the top of the tunnel will be unstable, it will even collapse. Based on equilibrium arch theory and Terzaghi’s loose medium theory, this paper proposes the calculating formula of digging length and analyzes loose medium in a construction project.

Mechanical models have been established for four-lane and two-lane highway bias tunnels with different cover depths by using finite differential code. The mechanical behavior of loose rock masses is studied. The displacement and convergence ratio of surrounding rock are analyzed when the impact of shear dilation to the stability of surrounding rock is considered. From the numerical results, for the same conditions of dilation angle, rock property and cover depth, some conclusions are drawn that the shear fracture band of four-lane highway tunnel tends to be expanded to the ground than that of two-lane highway tunnel, that the displacement vector and crown settlement decreases with the increase in dilation angle, but the horizontal displacement of abutment increases, and that the influence of dilation angle on the large span tunnel is greater than that of small span tunnel.

In an area with dense and intensive buildings, the construction of shield tunnels will influence the subsiding of adjacent buildings. In view of soil disturbance, 2D FEM method is adopted in this paper to study and simulate the shield tunnel construction of adjacent structures. Our research indicates that surface settlement together with force and deformation of the lining increase by the existence of buildings, simultaneously, additional stress and deformation of adjacent structure are induced during tunnel excavation construction. L is defined as level distance from tunnel axis to building axis and D is defined as outer diameter of tunnel. When L/D = 0.5 to 2, great surface settlement is produced with more settlement difference between building head and tail, and the building is in danger in the region. At the same time, the value of inner force also increases obviously. Out of the region, the influnece on the buildings is ignored.

The face support pressure control is a key operation during earth pressure balanced shield excavation. Three-dimensional fast Lagrangian differential finite element method can calculate the large strain of material, which is used to simulate the influence of face support pressure to face movement and collapse. Deformation and collapse pattern is discussed, and the soil stress release is analyzed due to shield excavation. Some useful results from numerical simulation are given for controlling face support pressure.

EPBM excavates in gravel stratum, whose ground water level is high. The soil excavated in chamber has big permeability coefficients, and is poor in flow ability. It is difficult to apply the support earth pressure to the working face due to the permeation of groundwater. Soil conditioning is a way of adjusting the soil condition in pressure chamber and increasing support earth pressure, which can decrease the permeability and increase the flow ability. The three-dimensional fast Lagrangian differential finite element method which can reflect the large strain of material is utilized to study the contribution of soil conditioning to face stability. The relationship between soil permeability decreasing and support pressures is analyzed. Some results from simulation are given for controlling face pressure.

An accurate grasp of cavity shape, size and its change is the key to the cavity stability numerical simulation. The basic components, principle and monitoring way of CMS are introduced. In this paper, on the basis of the actual situation of Donggua Shan Copper Mine, the cavity model and geological model of the mine are constructed by using the Surpac software based on CMS. A method of constructing numerical computing model with the coupling of Surpac and Phase2 is put forward. The simulation calculation is carried out. The stability of cavities surrounding rock mass is analyzed according to the simulation calculation results. The research shows that the combination of the advantages of CMS, Surpac and Phase2 provides a new and effective way for numerical simulation research on the stability of rock engineering.

Based on the specific condition of the Pengjia Garden Tunnel, the original construction plan is optimized during the construction. According to the numerical simulation of the construction condition, the two sets of construction plans which have been adopted during the construction process have been confirmed, reasonable excavation sequence and supporting methods are also recommended. On the basis of the active construction plan, we can obtain the influence on the arch and surface subsidence caused by the various working procedure. Combining the massive information obtained by the scene gauging, the studies of the settlement of the vault and the surface settlement have been carried out, so that we can exactly forecast the coming developments such as destroy、deformation and so on. Based on this, we can also come to some related conclusions, these achievements not only provide the extremely important instructional function to the project so that it can be carried out smoothly, but also pile up experience and practice material for the similar project in the future.

Taking Pingnian Tunnel in Yunnan, which is the bias closely spaced and shallow twin tunnel with altitude difference in two tunnels and constructed by using NATM, as the engineering background and applying MARC finite element software, non-linear three dimensional numerical simulation of construction process under different lagging distance between the twin tunnel excavated faces is performed. It is found that the change of the excavated face distance has a stronger influence on the horizontal displacement than on the vertical displacement of each tunnel, and especially for the left tunnel. Longer of excavated face distance is, smaller displacements at tunnel periphery and pillar is larger than the ground surface settlement in the special area , and more deteriorative for some zone.

As current theoretical research on cavern-pile method for shallow buried underground excavated tunnels lags behind application, the three-dimensional model is established with finite element method based on the action-reaction model in design and calculation theory of underground structure. The stability and displacement of surrounding soil masses relevant to different parameters are analyzed by simulating the construction process with cavern-pile method for shallow buried underground excavated tunnels. The results indicate that the stability and displacement of surrounding soil masses are acceptable when the large-section or super-shallow-buried single-span tunnels are excavated with cavern-pile method for shallow buried underground excavated tunnels. The effect of surface subsidence controlling with cavern-pile method for shallow buried underground excavated tunnels is optimal when span is about 14 meters, and almost uniform when embedded depth is different. The displacement of surrounding soil masses is nearly identical for different height of tunnels. The research may be a guide when we choose the most appropriate construction method for shallow-buried large-section single-span tunnels, or constructing with cavern-pile method for shallow buried underground excavated tunnels.

In this paper, three-dimensional elastic-plastic finite element method is applied to the inverse analysis of initial field stress for underground cavities of a hydropower project. The results show that the distribution of initial field stress is reasonable, the calculated and measured values are consistent at measured point. It can be considered as the basis of follow-up numerical analysis and the geological model test.

The paper researches into the filled body’s deformation safety problem of technology of GERTCF under long time force, with the background of 3# coal bed of the S2-6 fully-mechanized coal winning working face in Changcun coal mine, considered the creep behavior of the material. The numerical calculation is used to analyze the deformation of the filled body within 3 years under the different sizes and different side pressures. The result of the material properties available can help to get the optimized range of the filled body designing.

Cavern tunnel diseases, mostly forming underground stress field under the action of damage, seepage, temperature and other factors, are very complicated nonlinear coupling process. In this paper, the author employs the stimulate- response coupling system being made up of Bui damage model and seepage field, the result shows that the diseases will form obviously when the coupling strength factor is about 0.5, with the cranny expanding and the damage increasing in the surrounding rock, the plastic Radius of underground rock is increasing with the porous hydraulic pressure, it speeds up the appearance of tunnel diseases. It has some positive significance to prove up the coupling mechanism, the repair and the the protection of the cavern tunnel.

Slope deformation and stability are influenced by geological conditions and external environmental factors and its displacement and deformation tendency may have such differences as complexity, variety and randomness of factors. Based on the analysis and summary of law of slope deformation and aimed at displacement-time curve of slope deformation presenting negative S-style characteristic with initial deformation, stability deformation and acceleration deformation in this paper, the variable-weight combination forecasting model with growth curve inverse function is built on the basis of measurement time series data of slope displacement. The contrastive analysis results with engineering application example show that the single forecasting method can approximately reflect deformation development trend of slope and have great error because the method based on the fixed model of known example, and the method which the paper presents can consider the advantages of different models and have application in deformation forecasting and instability warning of engineering project with high precision.

By using elasto-plastic finite element method (FEM) based on the technique of shear strength reduction (SSR), stability of slope reinforced with piles against sliding and the behavior of stabilizing piles in slope are numerically analyzed. The criterion of iteration non-convergence conventionally used for assessing the instability state of slopes is combined with that of the uncontrolled displacement at a certain characteristic node on the slope surface to evaluate the limit-equilibrium state of pile-soil-slope system, and its validity is demonstrated through comparative studies for typical example. Furthermore, a typical case slope reinforced with piles is investigated through numerical analyses. The results show that the potential slip surface determined by SSR-FEM is shallower than that by limit equilibrium method and limit analysis method for a slope reinforced with piles.

An analysis is made of the horizontal displacements that take place in an infinite slope, consisting of an elastic-plastic Mohr-Coulomb material and overlying an impermeable substrate, due to the rainfall infiltration. An attempt is made to establish a relationship between the horizontal displacements before failure and the slope safety factor. It is shown that the slope safety factor and the horizontal displacements are significantly influenced by the initial stress state, the parameters of shear strength of soil and the rain intensity, while the time of slope sliding failure is not done by the initial state of stress. And it is also shown that the less horizontal displacements before failure takes place in the slope consisting of the soil with less parameters of shear strength under the greater rainfall infiltration.

The basic principles of discrete element method and strength reduction method are introduced. The method of combining the 3DEC and strength reduction method is presented and applied to the stability analysis of a high slope of a hydropower station. The reduction coefficient in divergence stage of key points’ displacement-time curve is defined as the slope safety coefficient, and the critical slip surface and failure mode can be determined according to the velocity vector of a slope. Numerical results presented in the paper indicate that this method is reliable for jointed rock slope stability analysis compared with the Dijkstra limit equilibrium FEM and classical LEM method. For no considering the 3D initial ground stress field in 2D common SRM, based on the 2D analytical results, the 3D generalized geological model is set up to get the 3D stress field. According to the analysis of the stress distribution and the main problems in the project, the specific geological model with unit width is set up by the auxiliary joint in the 3DEC. Based on the 3D stress field, the SRM is carried out. The new method takes consideration of the influence of the 3D stress filed of the slope stability and bas made up the shortcoming of 2D common SRM. This method is a rational and efficient stability analysis method and is worth using in similar projects.

Aiming at how to simulate the uplift pressure of the interface between dam and foundation in the stress and stability analysis of dam with finite element method(FEM), different numerical simulation methods of imposing uplift pressure are analyzed. By comparing the influence on the deformation, stress distribution and stability of dam foundation rock, their applied range and limitation are indicated respectively for specific application purpose. At the same time, the influence of dam seepage fields on the dam deformation is discussed based on spatial seepage flow theory. The research shows that irrational results might be obtained when uplift pressure is used to act on one side of element of the interface between dam and foundation as face loads, and the numerical result calculated by using the buoyancy unit weight of concrete under the saturated surface can agree well with that calculated by the seepage-body-force. The research also indicates that the curtain and drainage hole have a considerable influence on the stress distribution and stability of concrete gravity dam.

How to solve the stability problem of a hydroelectric project has always attracted much attention of engineering geologists. In this paper, a systematic analytical method for the stability evaluation of a high slope is put forward, including engineering geology model establishment, 2-D numerical modeling with distinct element method and limit equilibrium method. This paper has the high slope of BT20 at the dam location area of Jinlingtai hydroelectric plant as the research case. At first, the engineering geological characteristics of the high slope is analyzed in detail, and one engineering geological model is established; secondly, the software UDEC is used to analyze the deformation characteristics of the high slope to determine the critical sliding surface, and the results accord with those conclusions based on the engineering geological analysis; finally the Modified Sarma method is adopted to calculate the safety factors of the slope under different engineering conditions. The sensitivity analysis shows that seismic actions and rise of underground water level have most dangers to the stability of the slope.

The strength reduction finite element method is used to calculate the deep base anti-slide stability safety factor of the power house section of Wujiang Shatuo Hydropower Station. This method is compared with the most dangerous slip surface search method based on genetic algorithm. The results demonstrate that the results of these two methods are fairly consistent each other; and the positions of slip surface are also much consistent.

A slope in Shaoguan of Guangdong Province is composed of soils with high water adsorption. Rainstorms usually decrease strength parameters of soils and lead to great landslide with severe soil disturbance. A popular unloading and anti-sliding supporting method usually cannot achieve a good treatment effect. The closely spaced steel-tube and compressive grouting method, with two or more line steel flower tubes drilling into anti-sliding section of sliding mass and compressive grouting, can reinforce the soil around steel tubes. The steel tubes and around soil can form a solid continuous integrality acts as a retaining wall. Steel-tube and compressive grouting improve the mechanical capability of soil obviously so that the stability of slope is recovered with special unloading along slope and drain measures together.

The slip surface, which has different grades, is the base of the slope stability analysis and the methods for ascertaining it are different with the different slope structures. For countertendency soft rock slope，it can not be ascertained from the distribution of discontinuities as usual. Combined with FLAC3D and limit equilibrium method, the stability of countertendency shale slope with block cutting by discontinuities failure model is analyzed. Based on the field investigation, the deformation and failure mechanism is studied, the different grades slip surfaces are obtained from the analysis of the strain, stress and their increment pictures from FLAC3D analysis and the factor of safety is computed respectively. The prevention schemes are decided with the considering of the sub slip surface and the prevention effect is analyzed by aiming at the dangerous area. The safety factors of two dangerous areas, which are computed by shear strength reduction, indicate that the stability of the slope after prevention is good. The method used in this paper can be used as a reference to analyzing the stability of countertendency soft rock slope. The consideration of sub slip surface in prevention design has some practical guiding values

A new measure for canal slope of expansive soil which uses geogrid to strengthen expansive soil and expansive soil as backfill is studied. Base on the consideration of some key factors such as the interaction between geogrid and expansive soil, expansion which is caused by absorbing water and softening characteristics, a new way of calculation is presented for canal slope of expansive soil which is strengthened by geogrid, and this method is verified by FLAC3d. The result shows that geogrid can obviously restrict the horizontal displacement of canal slope of expansive soil, so it is an effective measure and can be applied to practical engineering.

The stability of the 5th dam block of the intake of the Gongboxia hydroelectric power station is analyzed. Firstly, according to geological conditions, three-dimensional models are established. Then, the three- dimensional limit equilibrium calculation formula is deduced. Finally, the safety factors of sliding stability for different working conditions are calculated. The results show that the dam block is safe.

Dam base’s stability of Xiaowan arch dam has been investigated by using 3-D FEM according to the actual engineering requirements of Xiaowan power station on dam base’s shallow research. It is found that the weakest position between pedion and enveloping surfaces locates 2m bellow dam base. Face safety factors of the enveloping surfaces of different slip angles, will decrease with a decrease in slip angle.

The Rosenblueth Method is a simple and practical calculation method of reliability index as the probabi- lity distribution of all kinds of state variables does not need to be known, and only by using the averages and variances of state variables can one get the reliability index of soil slope. In this paper an explicit expression about landslide load-increased factor is deduced. Using the expression as the status function of reliability analysis and the advantage of Rosenblueth Method, a method of calculating the reliability of slope is put forward.

The parameters of peak strength are often used to determine the critical slip surface and the length of anchors in schemes of slopes’ reinforcement at present, in fact, the capability of resisting loads and deformation decreases in the slip surface after sliding, there are only residual strength existing. Therefore, a mixed method is proposed to reinforce slopes, that is, the critical slip surface is determined by the parameters of peak strength, while the length of anchors is determined by the parameters of residual strength. The research shows that the safety of the reinforced slopes could be improved by the mixed method.

In this paper,the analog simulation on the stress-deformation characteristic of one high concrete face rockfill dam is carried out. The conclusion obtained from the finite element analysis shows that the great influence of stress paths on rockfill’s deformation characteristics is reflected by Duncan E-B model and mid-point incremental method. The rockfill’s deformation is related to load mode, and same stress level and different stress path, rockfill’s deformation is different; optimized load path is important to control rockfill’s deformation for stage filling rockfill dam.

With the increase in building density in the city of soft soil district, there are often buildings around the deep-pit projects. It results in strict environmental constraints on deep excavation. It is mandatory to consider that the additional deformation brought by excavation can meet the strict requirements of the surrounding buildings in the design of deep pit project. So pit design is restricted by deformation control other than strength control. Corresponding calculation and analysis method using FEM is brought forward based on the numerical simulation analysis of the deep excavation adjacent to buildings. Calculations and analyses of the additional deformation brought by excavation to the surrounding preservation architectures are made towards the different preservation forms between pile foundations and shallow foundations. The calculation and analysis are also compared with the in-site testing results, so the necessity and reliability of calculation and analysis are validated, which provides a useful reference to the design and construction of similar deep excavation projects.

According to the execution situation of the project, the constitutive model of rock and soil and the seepage law of ground water are taken into account, a new mechanics model of the ditch is established , seepage and the stress field of foundation ditch in different working states are simulated by finite element method. Accordingly, some conclusions are drawn: during the process of excavation, deformation of the soil around the ditch occurs, the soil at the bottom of the ditch swells, at the corner, there exists a stress concentration, this point is a vulnerable area, it should be treated with caution. In addition, with the precipitation of the ditch, the deformation of the rock and soil around the ditch will increase gradually, this will affect the safety of the retaining wall and the building near the ditch, therefore, during the construction of the ditch, precipitation should be controlled cautiously.

Due to the difference of cognizing relations of rock structure, all kinds of methods of the foundation pit pit-wall soil pressure are put forward, which has impelled the development of rock mechanics greatly. Impersonally speaking, none of these calculation methods exiting now can reflect the change of the foundation pit pit-wall soil pressure very truly and exactly. According to centrifugal force, combined with plentiful truly measured data of the foundation pit pit-wall soil pressure, a calculation method of the foundation pit pit-wall soil pressure based on gravitational field is put forward. Corresponding calculation formula and application examples are offered.

Based on the southern pit of Senlin Park Station of Beijing Olympic Subway branch, FEM is used to study the main factors of deep excavation of subway station maintenance structure distortion, forecast the distortion of maintenance structure, complete the design of monitor project, study carry through the in-situ monitoring study of deep excavation distortion law. The results are as follows: the project of monitor of the southem pit of Senlin Park Station is practicable; the FEM calculation results of horizontal displacement of pile agrees with the in-situ monitoring results; the instance excavation method of separated layer and little portion excavation is effective to reduce space-time effect during the construction process; the steel pile brace is useful to reduce the deformation and moment of maintenance structure.

The open-cut technology is used in the Xinkai River running tunnel of the 16th bid of Shenyang subway engineering,and the cast-in-place pile system surported by steel brace is applied in foundation pit excavating.During the excavating,the pile displace- ment ,the stress of the reinforcing steel bar,the axis stess of the steel brace and the ground subsidence are monitored.The results got by monitor and the effects of the engineering indicate that the foundation pit using cast-in-place pile system is safe,and the foundation pit excavation has little effect on the environment.

Excavation and earth filling of foundation fundation pit under complicated geological conditions is one of the important problems in the underground engineering field. By considering complicated geological conditions, constrained conditions of structure and the interaction between structure and soils, this paper concerns about the nonlinear FEM numerical calculation of excavation and earth-filling of foundation pit by combining with the Western Long Tunnel Construction Project from Shenzhen to Hongkong. The characteristics and regularities of the calculated settlements in the excavation and earth-filling process are obtained. The results can be used as an important reference to the design and construction of engineering.

The protection of the Longpan Tunnel’s excavation which are right beyond two existing shield tunnels of Nanjing No.1 subway is presented. Corresponding to unstabilizing condition and stabilizing condition with high-pressure chemical churning piles, the existing shield tunnel’s upwarping deformation during the excavation is analyzed with ANSYS software of 3-D elasto-plastic finite element method. It is observed that the tunnel’s upwarping deformations were too great without stabilizing and are safet with stabilizing. The calculated results are compared with the in-situ observation data.

The displacement characteristics in the top of the cantilever piles and the squeezed branch piles, and the axial force and the distribution of bending moment of these single row piles for protecting foundation excavation are analysed by model test and numerical simulation, and that is also studied for the double rows squeezed branch piles. The model test and numerical simulation show that the displacement in top of the squeezed branch pile decreases, the multiple bending moments are distributed more evenly, and the maximum bending moment decreases compared with the cantilever piles. It is concluded that the double rows squeezed branch piles have many siginificant advantages, including displacement, structure stifness, axial force and bending moment compared with the single row ones, and the double rows squeezed branch piles is a reliable and economical method to retain and to protect foundation excavation.

Based on the slope reinforcement theory and experiences, the reinforcement scheme of a slope that is close to a road and an old building with eight-floor in the silt soil with deep fourteen-meters is designed. By means of stability calculation and analysis of the slope, the smallest security coefficients in the reinforced slope are analyzed. During the excavation of the reinforced slope based on this design, the displacements of the slope and the settlements of surrounding buildings are in the scope of security and requirement, and the successful construction of basement structures are guaranteed. The technology provided in this paper serves as a useful reference to the similar engineering.

The simulative analysis with the Mohr-Coulomb model of FLAC3D program is carried out based on the development of deformation for foundation pits of a high-rise building in Beijing. Comparing with the results of the in-situ monitoring, the deformation, collapse and support for the foundation pits are discussed. It can be shown that the Mohr-Coulomb model of the FLAC3D program can be used to simulate the foundation excavation and the collapse and the slope support very conveniently and accurately. The results obtained are safe and reliable. The FLAC3D program can be widely used in the simulation of foundation pits.

Flexural rigidity of SMW engineering method combination beam is calculated by subentry based on considering interaction of cement soil and shaped steel. Flexural rigidity of SMW engineering method combination beam of elastic stage is obtained. Load-midspan flexivity of SMW engineering method combination beam is deduced under double concentrated force based on energy principle of elastic mechanics. Bending resistance performances of two section forms of SMW engineering method combination beam are analyzed based on above research work. And it is shown that the analysis is consistent with numerical result well.

Seepage is always a difficult point and a hot topic. In recent years, some scholars have put forward calculation methods of earth pressure and water pressure(called convention methods) on retaining structure with seepage based on their research findings. In addition, the finite element program PLAXIS can calculate earth pressure and water pressure on retaining structure through seepage flow-strain coupling. The article compares calculation results between convention methods and PLAXIS, then finds there are definite errors in calculation results because their assumptions differ from the fact. And the article analyses applied condition of invention methods and points out that earth pressure and water pressue with PLAXIS are appropriate and believable under true waterpower conditions.

The excavation width of some deep foundations and underground structures ranges from several to hundreds of meters in engineering. The deformation characteristics of the retaining structures and ground of these deep excavations vary with the excavation width. The two-dimensional finite element method is adopted to investigate the deformation characteristics of retaining structures and ground with different ratio of the excavation depth to the excavation width. The numerical results show that the magnitude of ground settlement and basal heave as well as the magnitude of horizontal displacement of basal all increase nonlinearly with the ratio. The magnitude of horizontal ground surface displacement decreases with the ratio first, then increases. The lateral deformation of the retaining structure varies gradually from introversion-type to extroversion-type as well as overall movement towards the inside excavation with the increase in the ratio.

The liquefaction in earthquakes will cause the inclination of the buildings and lead to their loss of functions. No numerical methods, however, can simulate the behavior of the phenomena at present. To search for the key points in the potential numerical method of calculating the building inclination due to soil liquefaction, the simple shaking table test is conducted and the relationship of the inputting waves, the vertical dynamic stresses, the pore water pressures and the building settlements are investigated in the paper. The results indicate: (1) The pore water pressure model used in the potential method must be suitable for simulating the process of water pressure rising during the irregular loads and can exactly calculate the difference of the pore water pressures under the incident loads with same peak amplitude but different forms; (2) The pore water pressure model should be able to disrcribe the pore water pressure variation due to the anisotropic property of soil and can distingush the difference of the water pressures due to the compression and extension stresses; (3) The pore water pressure model should be able to calculate the effect of the consolidation ratios on the pore water pressure variation and can attain the actual process of water pressure for the soil below the buildings; (4) The potential method should be able to follow the tracks of the deformation process of the soil layers with the increase in the pore water pressure.

Based on Biot’s theory, the general solutions for a poroelastic half space subjected to moving loads and the fundamental solution corresponding to a vertical harmonic force applied at the interior of a saturated half space are developed via the Fourier transform and Hankel transform method. Utilizing Muki’s method, the second kind of Fredholm integral equation describing the dynamic interaction between a pile and the half space is obtained. Numerical results in the time-space domain are obtained by performing the inverse Fourier transform. Numerical results show that the moving load can generate negative frication at the side of the pile. The maximum axial force of the pile and the pore pressure along the pile side increase with increasing load velocity. In addition, the pore pressure concentration phenomena occur at the upper part of the pile.

Based on K.Terzaghi’s soil mechanics model and taken account of soil dynamic nonlinear constitutive relation,soil shear dliatancy, rigidity degradation, hysteresis and water-soil relative motion, multi-phased medium dynamics theory is used to analyze the wave propagation and dynamic response of sand layers under water, and an artificial boundary condition is analyzed to simulate the wave propagation in pore medium. A set of dynamic equations of soil layers under water are established, and the equations are discreted to be used to analyze the earthquake engineering problem of soil under water, a direct differential method is suggested to calculate the water pressure and porewater pressure and to study the sand seismic liquefaction under water.

Analysis of response of level ground subjected to earthquake is one of the most active research areas in geotechnical earthquake engineering. In this paper, seismic response including propagation of acceleration, development of pore pressure, lateral displacement and settlement, of a level ground consisting of 15 m saturated sand is analyzed, by using the finite element procedure SUMDES 2006, incorporating a critical state constitutive model for sand. Effects of model parameters on seismic ground response are studied by adjusting the values of parameter by 10 %. The analytical results show that, among these parameters, the critical state stress ratio M and , the intercept of the critical state line on the axis in the e - plane, impose stronger effect. Therefore, the accuracy of the two parameters should be secured when the parameters are calibrated against the experimental data. The results also imply that the number of parameter in the model may be reduced when it is applied to the analysis of seismic response of level ground.

It is a key issue to define the transient responses of submarine pipeline and seabed under wave loading in the design of submarine pipeline. Most previous investigations were only concerned with the soil response due to linear progressive ocean waves, and the effect of pipeline-seabed interaction on internal stresses within the pipeline are not well recognized. The pipeline-seabed interaction under nonlinear wave loading is investigated by using friction contact theory and the finite element method. Numerical results demonstrate that if the effect of non-linear wave components is neglected, the internal stresses in the pipeline and pore pressure in the seabed may be underestimated or overestimated probably.

Three-dimensional elastic dynamic responses surrounding subway tunnels subjected to subway dynamic loading are studied by numerical method. This paper considers the case that two left-right parallel tunnels transform into two up-down parallel tunnels. For this, a method of applying subway dynamic loading is proposed firstly, and then the dynamic response characteristics such as deformation and acceleration values etc. are analyzed. Calculation results show that at the middle position of the arch bottom of the tunnel, the peak displacement in the middle section of the tunnel is smaller than the peak displacement in the end section. However, the acceleration value has small changes. Besides, the peak displacement under the action of two cross subways is greater than the peak displacement under the action of single subway, and the peak acceleration is advanced.

The method of dealing with 2D calculation model of the cast-in-situ concrete thin-wall pipe pile composite foundation in dynamic characteristic analysis has been simplified and presented due to its shortcomings in current methods. It is systematically studied through the calculation program exploited by Geotechnical Research Institute of Hohai University that dynamic characteristics of this composite foundation is preferable to original foundation. The examples show that the horizontal acceleration of ground surface increscent but the vertical horizontal acceleration decreases, the holistic stress surface consistent except for the verticality, and the earthquake resistance of this new type composite foundation predominant from the result of dynamic shear stress calculation.

The developments of pore pressure and axial deformation of undisturbed samples are studied by cyclic axial shear tests. A model for predicting the evolution of pore pressure under cyclic shear loading is proposed. The dynamic shear strength under undrained cyclic shear conditions is determined, and the degradation characteristics of undrained monotonic shear strength after cyclic loading are also analyzed. The effects of confining pressure and the frequency of cyclic loading on dynamic shear strength are studied. Studies show that, under a definite axial strain, the cyclic numbers decreases notably with the increase in cyclic stress ratio. Besides, the static undrained shear strength is degraded with the increase in cyclic stress ratio.

The numerical experiment is mode by using finite element analysis. The dynamic responses are simulated for undamaged anchorage system and damaged anchorage systems by axis symmetry numerical calculate. For undamaged anchorage system, the signal of bar’s top speed fade down quickly as the surrounding-rock is hard and the bar’s bottom reflected signal is not clear. Meanwhile the signal of bar’s top speed fade down slowly as the surrounding-rock is weak and the bar’s bottom reflected signal is clear. For damaged anchorage system, the reflected signal of impairment is distinct as steel have impairment. When anchorage mortar has defect, the reflected signal of defect is indistinct but he bar’s bottom reflected signal is distinct.

Underground tunnels are usually considered to have good earthquake resistant behaviors. But as far as those earthquake damages of underground pipelines are concerned, underground tunnels can be damaged severely by the large relative distortion of surrounding soil layers. Accordingly, earthquake resistant behaviors of underground tunnels must be studied in detail. By considering the characteristics of soft soils in Nanjing, a representative soft site is selected as the groundwork of tunnels. By using ABAQUS finite-element software, the nonlinear dynamic soil-metro tunnel interaction is modeled by finite-element. The displacement and acceleration response of tunnels buried in three different depths are analyzed respectively. Results show that the relative displacement between the top and bottom of tunnels buried in soft site is very large. At the same time, the soil-structure interaction has a great effect on the displacement responses of tunnels.

Borrowing the idea of load/unload response theory in seismic prediction, seismic dynamic model is established, in which seismic acceleration on the boundary is regarded as load/unload process and relative displacement, velocity or acceleration is looked upon as response parameters, whole time history analysis is performed by finite element method and load/unload response theory, favourable exploratory of the application in dynamic response prediction is then attained through the above-mentioned theories. The results indicate that relative response parameters are more applicable of describing structure deformation, reflecting the dynamic mechanism of action than absolute displacement. Using Load/unload dynamic response ratio to identify the damage degree under seismic waves turns out to be an effective method reflecting the response degree.

For unfree ground with existing building, the sandy soil liquefaction potential under earthquake is studied by using numerical dynamic response analysis. The influence of building stiffness, width and building weight on liquefaction zone distribution is investigated through various conditions of calculation. In conventional cognition, the sand under building is difficult to liquefy. However, it is demonstrated by this numerical calculation that the actual situation may not always be always so simple. A zone with the shape of character “V” under building shows high potential of liquefaction, and is closely related to the building stiffness, width and building weight.

Using two-parameter foundation model and 8-node isoparametric element based on Mindlin plate theory, the FEM equation for dynamic response analysis of elastic plates resting on elastic foundation is derived by Hamilton variation principle. The effects of foundation and mass distributed within the plate are combined in the stiffness matrix and mass matrix of the plate, and the effect of the foundation outside the plate domain is taken into account by the boundary element method. The free vibration and forced vibration of a free edge square plate are analyzed. The calculated inherent frequencies are close to measured results. Forced vibration dynamic responses reach the maximum when resonance occurs. The dynamic responses of the plate with the given damp ratio tend to be the same as those with zero damp ratio during the steady vibration period. The damp can significantly decrease the resonant responses.

To simulate the seismic ground motion history in liquefiable soil layers, a revised effective stress method is proposed and verified. In the revised method, the non-linear behavior of soils and the process of rigidity attenuation due to liquefaction are considered by iteration in every stress cycle. The model which can calculate the water pressure of saturated sands under anisotropic consolidation is used in the calculation procedure. The method and procedure presented here are tested by comparing with the post-earthquake records and shaking table tests. The comparative results show that the calculated results are agreeable with the actual records and the shaking table tests on main features, such as the PGA, the changes of the acceleration histories during the liquefaction process, the time-frequency history and response spectra. Especially, the calculated results quite correspond to those of the shaking table tests for the liquefaction-induced increment of the acceleration response spectra. As a result, the revised method presented in this paper is practical to simulate the seismic ground motion in the liquefiable soil layers.

Based on the assumption that shear modulus of foundation changes linearly along depth, the dynamic response of non-homogeneous foundation is studied in this paper by introducing differentiating operator of structure and using the stochastic vibration theory for continuous linear system. Then simplifying upside structures as multi-degrees of freedom system and foundation as shear beam, the stochastic earthquake response of interaction between foundation and structures is implemented. Using those results, the dynamic reliability parameters of foundation and structural maximal displacement are obtained. The response analysis is implemented by mode superposition method, which has a definite conception and simpler calculation procedures compared with ordinary separation variable method.

Methods of determining ground motion parameters for geotechnical engineering are dispersed in different designing norms in China now. Though most of the norms have been revised since 2000, they are still somewhat rational. There are two norms related to seismic-resistant issued in 2001. They are Regionalism Map of Ground Motion Parameters in China (GB18306-2001) and Code for seismic design of buildings (GB50011-2001). These two norms provide basic principles for the work but there are still some differences between them in determining response spectrum of ground motion. The differences are discussed in the paper. Since the earthquake risk level is changed for different geotechnical engineering, geotechnical engineers with earthquake knowledge is the best technician for the work. The discussion in this paper is helpful for geotechnichal engineers to understand the key problem.

Based on the substructural analysis of soil-structural interaction, sleeper-subgrade-site is treated as a subsystem and separated from the coupled system of train-rail-subgrade-site, and the input of dynamic load is considered as a boundary condition. As a trial, the measured time history of the vertical velocity of the sleeper induced by high-speed train in-situ experiments is used as an input of dynamic load. By means of this method and ABAQUS software, the parametric studies of dynamic response of subgrade-site system induced by high-speed train are completed by making non-linear numerical analyses and considering train running condition on up-link and down-link under the different combination with train speed 265 km/h and 300 km/h. Some preliminary regularity is presented.

The dynamical traits and performance of spall-resistant steel panel in the structure with or without steel panel under impulsive load are simulated by the software ANSYS/LS-DYNA. On the analysis of the results of two cases, the rule of structure’s stress and the boundary effects on capability of steel panel are presented. Results reveal that the steel panel can effectively reduce the element’s maximal stress adjacent to the steel panel, improve the performance; boundary effects don’t affect the spalling. The work will provide reference for the design and construction of projects concerned.

When using nondestructive ultrasonic testing for concrete components testing is used, the amplitude is the most sensitive parameter to reflect the defects of the components. So the attenuation degree of amplitude can be the chief criterion of the components having defects when the testing process in nice coupling and consistent testing condition. In the course of ultrasonic testing, the velocity parameter is not sensitive for the little defects and the velocity will prominent descend when big defects, and the frequency parameter is also not sensitive for testing concrete defects. So using nondestructive ultrasonic testing for concrete components testing, the velocity and frequency parameter can only be the reference parameters. According to the contrast of the ultrasonic transit or non-transit crack, we can find that the ultrasonic figures have obvious difference and sometimes there will be big periods wave character when ultrasonic transit the crack. The veracity of the testing can be improved under the synthetically analysis of ultrasonic parameters’ change of ultrasonic kinematics and dynamics.

By replacing the dynamic stress-strain hysteresis loop with polygon, a simple method of determining the damping ratio of soils approximately is proposed. The method can use test results directly, and by using this method, the process of detemining damping ratio will be simplified. Then the results determined by this method and the traditional ellipse pseudo method are compared, differences are found between them because the actual hysteresis loop recorded in dynamic triaxial tests are not standard ellipse.

The safe evaluation of the development of the damage areas of the Fengman Concrete Gravity Dam subjected to the earthquake is based on the plastic-damage model for concrete by the soft of ABAQUS. The damage variable which is the label of the damage of the material or the structure is considered as a internal variable. In this process of calculation the two variables, one for tensile damage and the other for compressive damage, is considered. The dam-reservoir dynamic interaction resulting from the transverse component of ground motion is modeled by using the developed and generalized Westergaard formula added mass technique. The hydrodynamic pressures resulting from the vertical component of ground motion are assumed to be small and are neglected in simulation. The safety and the overload potential of the Fengman concrete gravity is known by simulation. At the same time, it is concluded that the damage can be used to evaluate the safety of the dams subjected to the earthquake.

Since the settlement of piles of composite ground under embankment is smaller than that of soil between piles, the friction stress on upper part of piles is negative. Therefore the deformation and stress theory for normal composite ground cannot be applied for composite ground under embankment. It is shown by experiments and numerical analyses that there is an equal-settlement zone respectively in the embankment, piles and substratum of composite ground under embankment where the settlement of different position of the same horizontal plane is equal. Therefore, three-equal-settlement-zone model is put forward for composite ground under embankment. Not only are the effects of parameters of ground improvement on composite ground under embankment taken into account by this model, but also the effects of height or thickness, bearing capacity of embankment and substratum are taken into account. The model is proven reasonable and practical by experimental results and numerical analyses.

In high stress zone of subsoil, nonlinear deformation is caused by structural damage during loading, and the increase in stress level leads to the reduction of soil rigidity. The applicable conditions of compression modulus, tangent modulus, correctional tangent modulus, deformation modulus and correctional deformation modulus are discussed in this paper, namely compression module is only suitable for the unidimensional consolidation settlement analysis of foundation in which subsoil rigidity increases while stress level increases, and the correctional tangent module is more reliable than tangent module for the consideration of correction has been given to the additional stress. In the same way, the correctional modulus of deformation is more reliable than modulus of deformation for settlement prediction of the linear elastic foundation bearing permissible load.

3-D finite element method is used to analyze soil’s lateral deformation mode in the free field state in this paper. On the basis of that, lateral deformation and moment variable regularity of adjacent piles due to surcharge loads on the ground is explored, including different loads, loading distances, pile spacings and so on. Analytical results show that, piles’ deformation and moment will increase with the increase in loads, and piles will gradually become curved. If other conditions are the same, pile moment decreases quickly with the increase in piles’ stiffness, when the piles’ stiffness gradually become large, the pile will take on global displacement. Pile spacing and surcharge loads distance have important influence on pile moment and deformation. Pile moment and deformation will diminish with the augment in pile spacing and surcharge load distance.

Using a typical construction project as an example, a general analysis and comparison are executed to the influence upon the determination of the bearing capacity of rock foundation from the laboratory test and in-situ loading test of rock. A conclusion is drawn that the measurement with data from the result of laboratory test of rock is lower than the data from experience, while applying the result of in-situ loading test of rock to measure the bearing capacity is more scientific and reasonable. According to in-situ loading test of rock,determinating the bearing capacity and modulus of deformation of the rock ,and then calculating the settlement of the building with obtained modulus of deformation, the result shows that it is very consistent with the observations.

Based on the software of finite element method(ABAQUS), the bearing and settlement performances of pile-net composite foundation under embankment load are analyzed by means of numerical simulation. The influence of the stiffness of the geosynthetics, the thickness of the cushion, the elastic modulus of piles and the pile distance on the load transfer in the composite foundation, the stress ratio of pile and soil, the surface settlement and the lateral displacement of roadbed are analyzed. By analyzing simulating results, some features are found on the bearing and settlement performances of pile-net composite foundation. For example, when the stiffness of the geosynthetics is increased, the differential settlement of pile and soil and the lateral displacement of roadbed are greatly reduced, and the stress ratio of pile and soil is increased; with increasing the thickness of the cushion, some mechanical behaviors such as sharing of load and pile-soil stress ratio are obviously improved. All these are of some significance to design and construction of pile-net composite foundation in the future.

To solve the problem of quantitative risk evaluation of the ground settlement, the interval estimation method to predict the ground surface maximum settlement is put forward in this paper, and thereafter the risk evaluation index is defined. The method employs the Response Surface Method(RSM) to approximately express the relation between the surface maximum settlement and the ground parameters, and determines the interval of the surface maximum settlement based on the interval analysis theory, which can deal with the effect of the parameter indeterminacy on calculation results. In the end, the application of the method is explained by taking a side drift of some station main body under construction in Beijing for example.

The feasibility of Terzaghi’s one-dimensional consolidation theory applied to complex engineering condition of layered soil foundation and multi-stage loading is analyzed based on the characters of the great area super-hill filled sand foundation engineering. The simplified calculation model and the corresponding one-dimensional consolidation program are given to calculate soil settlement. Combined with the reclamation port construction project in Shanghai, the consolidation settlements of filled sand and soft substratum are calculated and analyzed in details by the program. Through comparison between the results of calculation and centrifuge model test, the simplified calculation model is modified; and the method for predicting and estimating the soil settlement of deep filled sand and substratum is put forward.

To analyze the influence of foundation rigidity on the behavior of composite ground improved by rigid piles, FEM is used in this paper to study the influence of foundation rigidity on the stress ratio of pile to soil, friction resistance and the penetrating displacement of pile. And the parameter Ke which reflects the relative rigidity of foundation is proposed. Then by analyzing the development of stress ratio of pile to soil under different value Ke, the foundations are divided into three kinds----flexible foundation, half-flexible foundation and rigid foudation. Finally through a case study, applicability of the presented method is proved.

Low embankment can save the irreproducible land resources. Shallow solidified soil layer is a scientific and economic ground improvement method of low embankment. In this paper, CPTU is applied to the in-situ test of Yangtze Rive floodplain. Based on the test result, consolidation and settlement of the soft ground was simulated with the case of designing shallow solidified soil layer and not designing shallow solidified soil layer under the load of embankment gravity and plain strain conditions. The state of embank and settlement under spacial automobile load are also analyzed by FLAC3D on designing shallow solidified soil layer or not. The results indicate that shallow solidified soil layer changed the stress distribution of the ground, and superimposed stress reduced through stress diffusion effect results in the reduction of the settlement. The study also indicates that the total embankment stiffness increased by the stiffness increase in shallow solidified soil layer, which reduces the vertical displacement of embankment and enhances the embankment stability.

Putting back berm on the soft soil foundation is a method of ensuring the stability of the embankment or dam. The limit equilibrium method is commonly used to analyze the stability of embankment or dam with back berm, but there exists a difference between the results and the critical slope surface exist a difference according to the limit equilibrium method and its real value. In this paper, the stability of embankment with back berm under different working conditions is analyzed with nonlinear FEM strength reduction method. The calculation results show that its results are consistent with the real condition accorded well to the traditional limit equilibrium method. The stability of embankment under complicated loads may be judged by maximum height of the embankment. Actual engineering example shows that the strength reduction FEM and maximum height of the embankment were feasible to assess slop stability.

Based on the construction form of transition zone and the longitudinal and transverse stresses measured from the DK266+521 bridge-subgrade transition in Qin-Shen passenger special line, the longitudinal, transverse and in-depth settlements of track transition under traveling load are analyzed by finite-difference program FLAC3D, and the settlement with different factors such as format, material stiffness, and dimension is also studied. The results show that: the engineering effect of track transition in trapezium form is better than in inverse trapezium form; the graded broken stone should be intensive enough; the size of trapezium has little effect on settlement.

The conventional radial consolidation theory is based on the small strain theory, so a constant volume compressibility and a constant coefficient of horizontal permeability are assumed during the consolidation process. However, both the non-linear variations of and are as a result of reduction in void ratio during the consolidation process. The non-linear relations of - and - for normally consolidated clays can be represented by the general compressibility equation and permeability change equation, respectively. Based on Hansbo’s theory, the solution of non-linear radial consolidation of sand-drained ground is deduced and compared with Hansbo’s solution. Finally, the influence of non-linear consolidation parameter and preloading increment ratio ( ) on the consolidation process is discussed. The results show that and are two important factors which control the non-linear radial consolidation of sand-drained ground.

The subject of interaction between foundation-subsoil and superstructure has become a new and hot application subject in recent years. In this paper, the foundation-subsoil and superstructure is studied based on the theory of the interaction between them. By choosing appropriate three-dimensional mechanical models, finite-element program "ANSYS" is used to calculate and analyze these models. In the method of simulation, material nonlinear and boundary nonlinear are considered. As for soft hard different foundation models, the result of calculation indicates that different hardness foundation will produce the stress distribution in upper structure and foundation again. At the same time, the diversification regularity of subsoil internal stresses is obtained. This result has its theoretical and applied values.

Based on an indoor physical simulation test and FLAC numerical simulation method, changing regulations of pore water stress and total stress of roadbed along reservoir or river are studied in the dynamic fluctuation of river or reservoir water level. And the results of the two methods are congruous. It’s been proved that when water level rises, the whole changing trends of water stress and total stress are both increasing, but the increasing value of earth stress is smaller than that of water stress. So the effective stress is decreasing. When water level falls, total stress is decreasing, but water stress is decreasing greatly. So the effective stress was increasing. Meanwhile, the method of FLAC numerical simulation can better study the regulation of data and get the continuity of data. Therefore, FLAC finite difference method can be effectively used to simulate the changing conditions of stress field and seepage field of roadbed along reservoir or river under different hydraulic boundary conditions.

When deep and thick soft ground is improved by vacuum preloading, lateral contract deformations will be induced in the soils, and this is beneficial to ground stability. On the other hand, the lateral deformation towards the vacuum preloading area will have an adverse effect on the adjacent buildings, underground pipelines, road embankments and other structures. Serious engineering failures may take place, such as crack of the pipelines, collapse of the retaining walls, and damage of the road embankments. In order to investigate the impact of the vacuum preloading on the surrounding soils, FEM analysis has been carried out, considering the influence of soils’ tension crack. The variation behavior during the vacuum preloading process is studied on the settlement at different depths and at different distances away from the preloading area. It has been found that the calculation results from the FEM analysis based on the Biot’s theory and the consideration of tension crack are consistent with the measurement results of the settlements and the extents of the influence outside the preloading area.

It is very important to measure the stress in the reinforced geotixtile in the embankment, which can help us better understand the effect of the reinforcement. However, it has been proved not only to be a urgent task, but also a difficult one. The paper describes the arrangements and installation of instruments for the field measurement of stress in the geotextile reinforced bedding course for a breakwater in a port in north China as well as the results of the field measurements. Analyses are made of the magnitude and behavior of the tensile stress of the geotextile in the bedding course of the breakwater and the relationship between the tensile stress of the geotextile and the settlement of the foundation of the breakwater. The measured tensile stress is far lower than the designed tensile force. Hence, a new question is raised how to consider the magnitude of tensile stress in the stability analysis of geotextile reinforced bedding course.

High-frequency vibratory hammer sheet wall technology is widely applied to sand levee foundation in vertical cutoff wall construction. To explore a construction method of vertical cutoff wall dealing with sand-gravel levee foundation in Dongting Lake areas, some improvements of this technology including construction techniques and flow chart are made, and computer control in the course of construction is realized, then this method is applied to Zhoujiawan project. And some detections including enclosed well test, coring bit and piezometric tube are used to verify the effect of thin cutoff wall. Experimental studies indicate that improved high-frequency vibratory hammer sheet wall technology has the advantages over traditional grouting technology, such as continuum, integrity in forming wall, good anti-seepage effect, high construction efficiency and low costs, and it is an effective kind of vertical cutoff wall technology applied to sand-gravel levee foundation, it can be used to treat with the levee project in Dongting Lake areas and any other region with the same geological features.

To get useful no-linear analytical resolutions from load-transfer differential equation, it is very important to establish a relationship model between axial force distribution function and displacement distribution function, i.e. U(z)-?(z). In this paper, the exponential model is selected by means of the method setting up experience formula, the shapes of curves of U(z)-?(z) gained by geometric construction method and the tentative calculations to many other models. The meanings and determining of the parameters in the model are discussed. The results show that the parameters ?, b only has a connection with the displacements of top and bottom on uplift pile.

Based on a new highway subsoil reinforce measure by using both geogrid and pile, the plane strain finite element method is used to calculate the ultimate bearing capacity of the foundation of road embankment. Finite element model of the geogrid-reinforced and pile-supported foundation of the embankment is built by PLAXIS. The efficiency of the geogrid on top of the piles to improve the soft soil foundation is proved in this paper. With the rate of replacement unchangeable and changeable, the laws of the effect of the pile diameter and distance in improving bearing capacity of the foundation are presented, in order to propose some reliable and valuable suggestions in the pile-supported foundation optimized design.

There is no a unified theory till now to compute the prestressed force of the cable. A new method for computing the prestress force is put forward by analyzing the existing methods for computing the cable prestressed force in design of anti-slide pile with prestressed cable. The cable, anti-slide pile, and the rock-soil surrounding the pile are regarded as a whole. Firstly, the total force can be got in the cable according the long-term load when the moments on the both side of the pile are equality; then to compute the prestressed force on the condition of compatible distortion. And comparing with others method in a landslide which crossed with a highway; the new method can make the force in the pile better. So the structure of pile-anchor can do better in protected system.

In order to compare with load transfer mechanism of rigid pile and flexible pile, static load test of cast-in-place pile and cement mixing pile is carried out. Stress meters are embedded along cast-in-place pile shaft and strain meters are embedded along cement mixing pile shaft .Sensors are monitored in the process of static load test. Different types of piles are analyzed and obtain some meaningful conclusions good for design and construction are drawn.

There are a number of solutions to vertical ultimate bearing capacity of single pile, but so far a feasible and economical method of determining the vertical ultimate bearing capacity of single pile has not been presented. So based on the cusp catastrophe theory, the calculating formula of the vertical ultimate bearing capacity of single pile is deduced in this paper by means of static loading test and parabola method. A case history proved that the calculation results are in accordance with the measured results well when the value of the deformation of piles is small, while when the value of that is big, the calculation results will deviate from the measured results. The inference in this paper can apply to practice.

Based on comparative analyses of slope stability of embankment on composite subgrade by using limit equilibrium method and finite element method, it is revealed that the calculated safety factors by LEM and FEM can be significantly different when the reinforcements in composite subgrade have dominating influence. Embankment stability can be well predicted by strength-reduction method by using plaxis software. It is further investigated that for embankment on composite subgrade the potential failure patterns of reinforcement columns such as bending, rotation and extension, other than direct shearing through reinforcements, made the difference in calculated safety factors by LEM and FEM. Therefore, for embankment stability analysis with interaction between soil and reinforcement in composite subgrade, LEM may overestimate slope stability and its applicability should be checked with caution.

It is of great importance to precisely appraise the mechanic characteristics and provide credible design parameters of soils for the design of foundation engineering. At present, the strength and deformation parameters are tested by different test methods whose precisions differ from each other, and the soils are disturbed inevitably to some degree, so are the stresses in the soils. The self-boring in-situ shear pressuremeter test, on the basis of the conventional pressuremeter test and the indoor direct shear test, adopts the self-boring technique, sends the probe to the preplanned depth of soils, tries its best to reduce the disturbance and holds the initial stresses in the earth. The unique structure and loading method make it possible to directly attain many mechanic parameters, such as the strength and deformation parameters, earth pressure at rest, coefficients of subgrade shear reaction, pile friction and so on. And the self-boring in-situ shear pressuremeter test is a testing technique in the drilling boreholes, so it can obtain the mechanic parameters of different depths in the soils.

The high pressure pressurement test(PMT) and wave velocity measurement of boreholes are used to get some important information about rock characteristics in cretaceous red layer in Changsha district. Based on the comparison of physical properties between PMT and wave velocity, using the synthetical analysis of multi-parameter, efficient information about rock werthering and strength is achieved. The correlation equations are established for characteristic parameters of dynamic and static properties of soft rock. It is proved that the combined sound wave velocity-pressurement test method is a rapid, economic, and efficient method on in-situ measurement in engineering investigation.

Based on the user subroutine UMAT platform of ABAQUS software, the redevelopment process of Duncan-Chang constitutive model is introduced; the simulation method for the surcharge preloaded soft soil foundation with sand well is discussed by using ABAQUS. A case study shows that the computation results are consistent with the practical data in site.

According to the formation principle and change characteristics of vacuum seepage field in the reinforced zone during vacuumizing, the formation process is divided into two stages, unstable seepage stage and stable seepage stage. Different seepage discharge calculation formulae are used, and the curve of seepage discharge is obtained. According to the change characteristics of underground water dynamics, the THEIS model and DUPUIT model are used to calculate the groundwater level of different time.

To investigate the calculation of critical load for super-long pile widely used in engineering, elastical resistance of soil on the side of pile is taken into account. The soil resistance on the side of long pile is assumed to consist of two parts. By choosing suitable wrapping function of pile, the critical load is solved by Rayleigh-Ritz method, and then the relations between resistance model and the critical load and calculated length of super-long pile are analyzed. The result shows that the critical load of pile depends on the length of pile in the soil, reduction coefficient and other pile-soil system parameters.