ompression line and critical state line can be simplified as parallel straight lines in space within the framework of critical state soil mechanics. Inclined ellipsoid is the simplest yield surface shape of the model that can take account of anisotropy. Combined with critical state soil mechanics, formulas of undrained strength under consolidation have been proposed; these formulas can be used in triaxial stress conditions and plane strain conditions. Based on a large number of experimental data, the formulas are proved to be true. If other parameters taken as constant, we can get linear relations between the undrained strength ratio and the effective frictional angle. A simplified formula has been proposed for engineering application.

Based on the Biot’s theory, dynamic responses of layered saturated soil under moving loads are studied with the transmission and reflection matrices (TRM) methods. Numerical results of the displacements, the pore pressures and the stresses are obtained by performing inverse Fourier transformation in time-space domain. Some numerical examples and corresponding analysis are presented. The presented methodology is validated by comparing solutions with some known results. According to the analysis, it is concluded that the occurrence of softe interlayer in the layered half space enhances the vertical displacement and pore pressure. Comparing with the homogeneous soil, the response of the multi layered half space tends to contain higher frequency components and exhibits larger magnitude.

Considering two effects of hydration time and temperature, the swelling deformation and strength characteristics of expansive soil are studied through the laboratory test. The results show that the swelling process of expansive soil after saturation could even still continue for quite a long time, which makes the strength of saturated soil gradually reduced with the extended hydration time. Moreover, during the swelling process of expansive soil, the higher the hydration temperature is, the greater the swelling rate and ultimate swelling ratio are, which results in the strength of saturated soil gradually decreasing with the increasing of hydration temperature. Therefore, the shear strength parameters of saturated expansive soil should consider the effects of hydration time and temperature; and a more suitable formula for expressing the variable shear strength is proposed.

Based on the biaxial test by PFC2D, the behavior of sand with different densities under monotonic loading is simulated by discrete element method. The evolution law of macromechanism behaviors and mesofabric parameters is studied during sand soil progressive failure process. A statistic code is developed by fish language in PFC to study the evolution of microscopic fabric parameters including coordination number distribution, contact normal, normal contact force and shear contact force. The relationship between mesoparameters and macromechanical response can be achieved. The mechanism of induced anisotropy, compaction of loose sand and dilatancy of dense sand are discussed by using the mesofabric parameters. The results are valuable for the studying of mesomechanism of sand deformation and the construction of mesomodel for sand.

Moraine Soils is one of the gravel soils that sedimented by glacial transporting and melting which including debris and other loose deposits before glacial period. So moraine soils have particular characteristics of erosion, transportation and sedimentaion. Because the moraine soils always include clods, macadams, gravels and sands, maintaining minus-cementation or argillaceous half-cementaion state, poor water-stability and easy disintegration. Moraine soils have been generally regarded as a problem on engineering treatment. Important step must be taken to solve the problem to obtain the strength behavior conclusively. But this step must be based on large scale with the structure of the moraine soils. Considering this, undisturbed samples and same dry density, different moistures remoulded samples are taken to large scale direct shear tests. The result shows that the undisturbed moraine soils have some structural strength, and the strength of the remoulded moraine soils falls along with the moisture increases.

The soil static and dynamic universal triaxial and torsional shear apparatus was employed to perform both undrained cyclic triaxial tests and cyclic torsional tests for undisturbed silty soil samples. Based on the experimental test results, dynamic characteristics of both deformation and strength of undisturbed marine silty soil is investigated. The maximum dynamic shear modulus and the dependency of dynamic shear modulus and damping ratio on shear strain are defined through cyclic triaxial shear tests. An empirical pattern is established for residual pore water pressure generated during cyclic shear which is represented by a hyperbolic function with respect to the number of cycles of dynamic stress. And an empirical formula is developed to describe the cyclic strength with respect to the number of cycles. The related parameters involved in both patterns of pore water pressure and cyclic strength are determined by experimental tests; and their dependency on the consolidation stress ratio is clarified. The experimental data achieved from cyclic torsional shear tests are used to validate the results from the triaxial shear tests. It should be more conservative using the cyclic strength determined by triaxial shear tests in geotechnical earthquake design.

Softening phenomena will occur in normally consolidated soft clay under cyclic loading because of the increase of pore pressure with progressive cycle number. However, in overconsolidated soft clay, negative pore water pressures may develop at the beginning of cyclic loading, despite the fact that softening phenomena occurs simultaneously. It is evident that this behavior is contradictory to the effective stress principle. In addition, the preceding approach to cyclic softening characteristic of cohesive soils is to establish the relation between softening index and cycle number which doesn’t encompass the pore water pressure generation that occurs simultaneously. The residual pore water pressures correlate to softening index of overconsolidated clay subjected to uniform stress-controlled triaxial loading are investigated. A cyclic softening-pore pressure model is proposed based on the tests. The model shows the influence law of cyclic softening characterstic of overconsolidation.

Based on a series of laboratory tests on soft soil in Nansha, Guangzhou, involving direct shear test, unconfined compression test, consolidation test, the structural characteristics of the regional soft soil are studied. By using undisturbed and remoulded soil samples, shear deformation, shear strength and consolidation properties of the structured clay which indicate the significant structure of the soil and the effect on engineering property are analysed. The test results show that the shear strength of disturbed structure clays obviously declines and the compressibility increases; the consolidation process of undisturbed samples can be considered as three phases, which relating to structure yield stress. For remoulded structured samples, the dividing line of compression and secondary compression by compression-log time curve, obtained from oedometer tests, is more obvious than undisturbed specimen, in case of loaded be same. It can be concluded that structure yield stress, which can be defined by compression coefficient a-consolidation pressure p curve, is one of the important factors for controlling deformation of structured clay. The influence of structure on mechanical properties decreases as the consolidation pressure increases. When consolidation pressure is higher than full structural yield stress, the effect of structure can be neglected.

Researches on saturated-unsaturated soils became a hot issue in resent years. In fact, it is very difficult to analyze the mechanical behaviors of soil because of the pore water pressure’s existence. Based on the relationship between permeability and matric suction, numerical simulation of unsteady seepage analysis of an ideal isotropic embankment is presented. And the dynamic change of the seepage field is temporally and spatially discretized and inducted into the stability analysis of the embankment slope. Regularity of the minimum safety factor of the slope is discussed by applying the limit equilibrium theory and Morgenstern-Price slice method to show the inherent relation between seepage and landslide.

The shear strength and unit weight have much relations with the stability of sandy soil surrounding rock of tunnel. From the factors influencing the stability of sandy soil surrounding rock and classification of surrounding rock, the feasibility that using sandy soil surrounding rock basic quality index (SBQ) as a synthetic factors to evaluate the stability of sandy soil surrounding rock of tunnel is explored. It is found that the SBQ can be a representative value of other physico-mechanical indexes. The quantitative expressions of other physico-mechanical indexes and the SBQ are presented.

In soil nailing, soil nails have the functions of reinforcement and anchorage, and the forces and deformations are changed with the construction process. On the base of the stability analysis, it is reasonable to calculate the soil nail forces by the incremental method. In soil nailing, according to the interaction between the soil and nails and the characteristic of soil nail forces at the slip surface, the upper-bound method can be used in the calculation of soil nail forces. In the calculation by the upper-bound method, the incremental coefficients of soil nail forces are decided based on the kinematical velocity field and the relationship between the forces and displacements of the soil nails. In every excavation of the cut, the energy equation of upper-bound method is used to obtain the dissipation power by the soil nails. According to the power dissipated by the soil nails and the incremental coefficients, the incremental forces of soil nails are calculated. Then, the total soil nail forces are obtained by the accumulation of the whole excavations. At last, an engineering case is presented, and the calculation results by upper-bound method are compared with other methods. The comparisons show that the upper-bound method here is effective and exact.

A new method for determining hydrogeological parameters of aquifer from recovery data is proposed. The possible difference between releasing water coefficient of aquifer in the stage of water level declining and water storage coefficient as water level rising is taken into consideration. In order to derive the equations for estimating the hydrogeological parameters of aquifer, the same simplification way for two well functions describing two drawdowns is taken; one of these drawdowns is caused by continuous pumping, and the other is caused by imagined recharge with the same pumping rate after pumping stops. This means that the first three terms in the series expressions of the Theis’ well functions are taken as simplified expresses of well function, and the simplified condition is that two dimensionless times are and . Under such simplifications, transmissivity, water storage and releasing water coefficients may be estimated simultaneously. According to the differences between storativity and releasing coefficient, the deformation reversibility of tested aquifer between discharge stage and recharge stage may be judged. Finally, an example is given to show the application procedure of the proposed method.

Tensile strength is an important mechanical property of rock. In Brazil test of a flattened disk specimen measuring tensile strength of rock, the central angle of the flats has great influence on measuring tensile strength．But there is no restriction in the test, which makes tensile strength of rock obtained by the test very scattering. Digital image processing methods are used as a measurement tool to construct a numerical representation for the actual spatial distribution of different materials and components in rock samples, which is introduced into rock failure process analysis (RFPA2D), and numerical model of Brazil tests of granite flattened Brazilian disk specimen which considers the actual heterogeneity is established by processing its digital image. Using the numerical model, the influences of central angle of flats on stress distribution along axial line, splitting failure modes and tensile strength are analyzed; and reasonable range of central angle of flats is obtained, which should be in the range of 20??30?.

According to project example, the vibration effect due to deep and thick silt by blasting compaction is monitored and analyzed. The decay law of vibration velocity with distance by linear fitting is obtained; and experimental research in aspects of controlling single deck maximum explosions, ascertaining reasonable millisecond delay time, regulating transmission direction of vibration waves is carried out. Results show that vibration effect is effectively controlled by these measures. Controlling single deck explosions is the most basic factor; the amount of explosions should be decided by field experiment; when single deck explosions are the same, the maximum vibration velocity can decrease by 20 percent to 30 percent if we set the millisecond delay time more than 200 millisecond; and vibration velocity in the direction of explosions central line is 15 percent to 25 percent lower than that in its vertical direction. The research result may provide a model for the similar project.

By using model test, construction schemes for metro station of twin-bore tunnel with expanding construction based on shield tunnels are studied. Main research contents are the feasibility of expanding construction method and the displacement rule of stratum displacement. The contrast between results of the model test and 2D numerical simulation of the expanding construction with the finite difference method is carried out. Results show that the construction scheme for metro station of twin-bore tunnel with expanding construction by central drift method is feasible. But reinforcing the surrounding rock of the bottom and vault of tunnel arches are necessary during the expanding construction. The vertical displacement distribution of surrounding rock appears the U-shape after expanding construction. The displacement of surrounding rock decreases with its mechanical parameters. Reinforcing the surrounding rock at the bottom of tunnel arches is an effective method for reducing its displacement. The settlement curve of the ground surface appears approximately normal distribution, and the influencing breadth is 3 times as breadth as station of twin-bore structure.

The Dayantang landslide in Qingtaiping town of Badong county, Shuibuya reservoir, slipped on June 15, 2007. The climbing height of surge reached 50 meters, which caused casualty along the channel. In order to solve surge triggered by the Dayantang landslide, the surge is summarized into two kinds of surges, volume-surge and impact-surge, on the basis of the mechanism of landslide surge, respectively. The volume conversation law and the displacement formula of mass below water lever are used to calculated the initial surge height. The decay process of landslide surge is divided into sharp-decay stage and slow-decay stage; and it is assumed that the sharp-decay stage is a kind of exponential decay, and the slow-decay stage is a kind of water head loss with propagation distance in open channel. The propagation height and climbing height of landslide surge along bank are deeply discussed; and the calculation result is compared with survey of climbing surge. The result has reference significance for the research on propagation of landslide surge in the reservoir.

Comparative experiment research on dynamic deformation behaviors of lightweight sand-EPS beads soil (LSES) with sand is taken with mixing proportions determined by dry density. Test results indicate that Ed (dynamic elastic modulus) of LSES and sands both decrease with the increase of strain; and Ed of LSES with different contents of cement and EPS beads are all larger than that of sands. Ed of LSES and sands both increase with the increase of ?c (confining pressure), but the influence of ?c on LSES is more notable. D (equivalent damping ratio) of LSES and sands both increase with the increase of strain. D of LSES approximates to that of sands when content of cement is low, and D of LSES is smaller with higher content of cement. D of LSES and sands both decrease with the increase of ?c , and the influence of ?c on D is similar.

For over-length and large-diameter bored piles with dense distribution, especially for high-pile group, in the solidification process pile concrete brings intensive compacting effect on soil around the pile. It is significant for enhancing integrity and bearing capacity of pile group, and controlling settlement of the foundation. The purpose and scheme of the test are designed according to the super-large pile group foundation of Sutong Bridge. The test gives the distribution and change laws of lateral compacting pressure. It is shown that the lateral compacting pressure increases continuously after pouring the pile, especially for the concrete in flow-plastic before initial set, the increase amplitude is 8.4 to 13.5 percent. The lateral pressure still keeps 0.8 percent of increase from initial set to the 14th day of the test.

According to results of the triaxial compressive test of saturated saline frozen silty clay, the stress-strain relationships are studied in the process from the beginning of test to the soil samples destroyed. And maximum values of initial elastic modulus and principal deviator stress are calculated by using Duncan-Chang hyperbolic model. The results show that the values of initial elastic modulus and principal deviator stress increase with salinity reducing and temperature falling. In order to analyze the action mechanism of salt content affecting on soil strength, a new concept, the relative temperature, is put forward, and the linear relationship of the relative temperature and the compressive strength are described. The relative temperature is an integrative conception to take into account how some elements, i. e. salinity, test temperature, etc, affect frozen soil characteristics, so as to express the relationship of saline soil and non-saline soil by the relative temperature. And the mechanical characteristics of saline soil is studied by it of non-saline soil.

The soil microstructure has a significant influence on engineering mechanical behavior. SEM tests are dealt with Shanghai intact mucky clay in different consolidated pressures during one dimensional consolidation test. And particles (including aggregate shape, mean surface area and orientation distribution) both from horizontal cut plane and vertical cut plane of the specimen are analysed and compared. In addition, the pore of soil has been analysed by means of mercury intrusion porosimetry test. Through these analyses, it is concluded that the soil represents character of damage gradually and material anisotropy during loading condition from tests above.

A series of triaxial compression tests, composed of isotropically and anisotropically consolidated undrained compression (ICU and ACU) tests and constant shear drained compression (CQD) tests, are carried out on undisturbed saturated loess by GDS apparatus. The results of ICU and ACU tests performed at the in-situ stress level show that the soils are of consistently strain-softening in the stress-strain relations. The steady-state line and the potential region of instability are obtained from ICU and ACU test results. A necessary condition for liquefaction is that the soil state initially lies in or is brought into the potential instability region; CQD tests demonstrate that the mobilized friction angle is far less than the steady-state angle and that the soil experiences undrained contractive failure suddenly at very small strains when its stress path during drained loading tries to cross the potential instability region; thus the proposed instability region is validated. Based on the location of the region of potential instability and the stress state of slope soil, a method of static liquefaction analysis is proposed for loess landslides caused by rise in groundwater table.

With rapid developments of metro construction in China, the safety evaluation of pipelines near tunneling is one of the key technical problems urgent to solve. On the basis of understanding basic laws of ground movements, an empirical or semi-empirical method of longitudinal strain calculation and safety evaluation of rigid pipelines is put forward. Generally it is not necessary to consider the details of pipelines, and only a few parameters are involved, so the method is easier to be used in engineering, and can be used to evaluate the latent damages of pipelines rapidly. The method is particularly fit for the case of no sufficient data or especial sensitive pipelines when the conservative estimations are needed.

The law of expansive power of sandstone on the upper plank of coal bed in Guhanshan coal mine in Jiaozuo under high temperature is studied; and both the ultrasonic wave parameters and the porosity are also studied in order to find out the mechanism that causes the expansive power of sandstone under high temperature. The results show that the expansive power of the sandstone will become great gradmally when the temperature increases; and expansive power of the sandstone is small when the temperature is under 300 ℃; but it will become greater when the temperature is greater than 300 ℃. The study of the ultrasonic wave parameters and the porosity also indicates that the expansive power of sandstone will appear.

Applying electromagnetic wave velocity singly for karst survey, there are limilations because of multiple solutions, and so does attenuation tomography technology. And the veracity is reduced. Based on the electric differences between karst cave and ambient medium，which are directly reflected by resistivity and relative dielectric constant, theories of resistivity and relative dielectric constant tomography are put forward, depending on the theories of electromagnetic wave velocity and attenuation tomography. Furthermore, it is applied to project. It is proved that the technology, relying on resistivity of electromagnetic wave and tomography of relative dielectric constant, is doable by analyzing four parameters, such as electromagnetic wave velocity, attenuation, relative dielectric constant and resistivity. A method of multi-parameter tomography compositive analysis is formed. As a result, the veracity of applying tomography by electromagnetic wave for detecting karst cave and it’s filling increases.

Drawdown of groundwater table causes the changes of net mean stress and matric suction in unsaturated soil, and then induces volume change of soil mass. By using the GDS unsaturated triaxial apparatus, the total volume change and water content change of the remoulded unsaturated soil in the test are studied in the drying process. For a typical foundation pit, ABAQUS is used to simulate two dimensional saturated-unsaturated steady-state seepage flows induced by foundation pit dewatering. Based on test and simulation results, using Fredlund constitutive model and effective stress theory, subsidences of unsaturated soil and saturated zones are estimated respectively for different drawdown depths. Computed results indicate that in total amount of subsidence, the portion of subsidence of unsaturated soil zone cannot be ignored. The contributions of unsaturated soil zone to total subsidence increases as drawdown depth increases.

A new elastoplastic constitutive model is presented in the framework of continiuum irreversible thermodynamics. The Mohr-Coulomb criterion is adopted. There are three internal variables adopted in this model: plastic strain , isotropic scalar damage variable D which describes the character of damage. The new constitutive relations strictly satisfy the basic requirement of thermodynamically consistent theory. Numerical validation of the prposed constitutive model has been carried out at local level. Uniaxial compression of concrete specimen under various confining pressures has been simulated. Results indicate the effectiveness of the proposed model.

Risk evaluation of concrete gravity dams subjected to strong earthquake is one of the key problems of performance-based aseismic design. Risk assessment in view of technology and economy is on the base of decision-making, and countermeasures of aseismic optimization are put forward. By using classification criterion of destroyed degree due to strong earthquakes given by researchers, earthquake hazard and aseismic fragility assessments of dam, aseismic risk model is established; and aseismic countermeasures are analyzed. The Jin’anqiao Concrete Gravity Dam under construction is taken as the example for illustrating the risk assessment. It is shown that the model is basically applicable to risk assessment of concrete gravity dams subjected to earthquakes.

Grouting gravel pile is a new technique of pile. It has the usual effectiveness of rigid pile composite foundation, furthermore, mechanical properties of soil around pile, which can increase bearing capacity of composite foundation and reduce its settlement. The property of soil around pile is tested in field before and after the pile is constructed, from which the grouting impact range and regularities of distribution are obtained. In allusion to clay soil around pile, the calculation formula of range impacted by grouting is obtained out by analysing balanced equation of cell cube in plastic zone. The calculation result is consistent with the grouting impact range obtained from in-situ test, so as to prove the rationality of calculation method.

It is very necessery to measure the swelling pressure of expansive soils in-situ, due to the laboratory results can not usually reflect practical situations. Using “ loading-swelling method ”, by use of the results of loaded swelling rate tests, swelling pressure values are obtained through linear interpolation. Field test rusults show that the swelling pressure can reflect the real situations. This testing method may have good applied prospects because of easily to operate.

The liquefaction for saturated silty foundation under dynamic loading is the important research content in the domain of aseismic design of high-speed railway. To analyze the liquefaction resistance and deformation characteristics before and after reinforcing saturated silty ground of Beijing-Shanghai High-speed Railway, a series of dynamic triaxial tests are carried out under two different densities with three pressure conditions of saturated silt in the laboratory. The increasing law of liquefaction resistant curves under two different dry densities of saturated silt, dynamic intensity and the process of bulit-up pore pressure are got from the test research. It can provide the scientific data to further analyze the liquefaction deformation characteristics before and after reinforcing saturated silty ground.

Simplified mechanical model of tubular pile or closed diaphragm wall is proposed base on elasticity mechanics. The stress components of piles in two load conditions are solved by semi-inverse method at first. One load condition is that uniform vertical shear stress acted on the left and right sides of pile shaft, another is uniform vertical shear stress acted on the pile top. According to superposition principle, the stress components of the pile with unit shaft resistance on both side and vertical load on the head are solved. The calculating formulation of axial force and unit shaft resistance are deduced; and good identity has been achieved between the formulation and traditional method. When uniform vertical shear stress is not equal on both sides, the stress components of the vertical loaded pile are also solved according to superposition principle. Then an analytical solution of unit shaft resistance-axial strain relationship by using semi-inverse method is obtained. Application of the analytical solution is illustrated with a model test of closed diaphragm wall. This solution will provide theoretical basis for data processing of outer and inner axial strains which are measured in the model test of axial loaded cast-in-situ tubular piles or closed diaphragm wall. Thus true and accurate test result can be provided for the research on foundation-soil interaction.

Taking a concrete gravity dam on common rock foundation for example, the curtain parameters of dam are studied by the improved genetic algorithm. Based on the depth of the curtain ploted out element and calculated by finite elements. The mathematical model of optimizing design is established according to the allowable seepage discharge, seepage pressure of dam foundation and the maximum hydraulic gradient of the curtain, the minimum cost of the grouting curtain regarded as objective function. Finally, the optimum combination of the curtain parameters is identified, for saving engineering investment.

Considering the viscous damping of the soil and soil-pile vertical coupled vibration, the differential equations and boundary conditions about vertical vibration of cast-in-situ concrete thin-wall pipe piles in axisymmetric homogeneous viscoelastic soil are established. The analytical solution is obtained by Laplace transformation method. A case study is given; and the results of analytical solution can well match FEM and measured waves. Moreover, by analyzing the effects of viscous damping coefficient on velocity admittance and complex dynamic stiffness, and the effect of damping coefficient of the soil below pile bottom on velocity admittance, the regularity of variations of vertical vibration characteristic with parameters is obtained.

A kind of geological disasters such as water bursting often occurs in karst area in the process of informational construction of tunnel, which bring momentous disaster and economic loss to construction safety, so the precise and immediate advance forecast to the development of karst is the key problem to be researched and resolved currently in tunnel dynamic design and informational construction in karst areas, which brings important theoretical significance and practical value. The method of forecasing karst-fractured groundwater in tunnel informational construction is firstly summed up, then TSP and infrared water detecting method are used synthetically to detect a special long road tunnel based on hydrogeological analysis, which gains good prediction results. It has guiding significance to similar projects.

A storm attacked the Heyuan area late June, 2005. The rainfall exceeded 1 000 mm. The storm triggered the unstable deformation of the k2 slope. Based on the Load/Unload Response Ratio theory, the deformation and stability of the slope are discussed by analyzing the response ratio of inner deformation, outer deformation and the reinforced structure of k2 high cut slope. The slope deformations on support and without support structure under the storm are analyzed by using finite element method, and the effect of the slope reinforced structure is assessed. The deformation ratio of the slope trends stable under the storm after reinforcement. k2 slope reinforcement can be met the stability of design standards.

In order to improve the design and calculation of laterally loaded piles, finite difference numerical analysis method which can calculate displacements and internal forces of piles under lateral load of trapezoid distribution is proposed based on nonlinear p - y curve mode of foundation coefficient. The finite difference formulations of displacements of piles are deduced in detail. Based on these formulations, computation and visualization programs of displacements, internal forces of piles and soil reaction are developed for design calculations of anti-slide piles and cantilever retaining piles for deep foundation pits. Taking the new pile cast-in-situ concrete thin-wall pipe pile (PCC pile) as anti-slide pile, a comparison study is computed. The examples show that this method is convenient and reliable. Numerical solutions are close to real solutions when finite differential segments are small enough.

In order to study the failure mechanism and ultimate bearing capacity of weightless subsoil under rigid and flexible foundations, comparative studies are conducted for flexible foundation, rigid rough foundation and rigid smooth foundation in the case that the effect of soil dead-weight was negligible. Mohr-Coulomb inside-tangent circle yield criterion under associated flow rule was adopted. The ultimate failure state of subsoil from linear elasticity to plasticity gradually was modeled by incremental elastoplastic FEM. Some conclusions are drawn from computational results of three kinds of foundations mentioned above and model test results in the literature. It is shown that the weightless subsoil under rigid and flexible foundations have similar ultimate bearing capacity; while development trends of vertical stress and displacement, critical edge pressures and slip surfaces are obviously different.

Based on engineering practice of south anchor of Runyang Yangtze Bridge, the south anchor applies new technology of frozen row-piles method. A new method of data processing based on time series improvement method of wavelet technology is put forward. It can combine the multi-step forecasting function of time series analaysis and the refined data processing function of wavelet. The result indicates that the forecast accuracy of time series dynamic forecasting model has been improved greatly based on wavelet improving time series analysis. It affords reliable guarantee for construction of deep foundation pit and reliable basis for information construction. It can provide much experience for deep foundation pit to which the frozen row-piles method is applied.

Three basic types of similarity relationship between the prototype and the model for dynamic structural model test and dynamic rupture model test are proposed in corresponding literatures. At the time the situation where various similarity relationships are applicable and the technique to ensure similarity for the different goals, to study dynamic behavior, elastic response and damage pattern, is discussed. The numerical simulation of model experiment of water-conveyance tunnel concerning fluid-structure interaction in soft soil is studied. Based on economic practicability of material selection for model test, the similarity relationship and the technique are proposed, which are validated through case study. The results of numerical simulation show that under the specific conditions, data of the model test can completely transfer to those of the prototype by using this type of similarity relationship, and getting more useful information. Some new ideas are introduced to keep the similarity of the hydraulic structures.

During the excavation of the diversion tunnel No.1 for Nuozhadu Hydropower Station passing through the fault, F3 in the process of excavation, the strain and stress distribution of wall rock is controlled by the rock mass mechanical parameters around the influence zone of fault F3. Aiming to evaluating the stability of wall rock because of the excavation of layersⅡand Ⅲ; firstly, it needs back analysis of the rock mass mechanical parameters and the initial stress field of the wall rock around the fault F3 by using the displacement monitor data after the first layer excavation. Then, modeling of the first, second and third layers excavation used the rock mass mechanical parameters and the initial stress field which get through with back analysis method. The stress-strain situation of wall rock surrounds the fault F3 has got. The compute results show that the restriction of the tunnel rock mass surrounds the fault F3 is released gradually; the stress of the wall rock is increased gradually; and the displacements of the wall rock are also increased gradually with the uninterrupted excavation. And the stress-strain in the center zone of the fault F3 is unbalanced in evidence. It is shown that the excavation of the tunnel influenced by the fault F3 is obvious, monitor and analysis of later deformation in this zone need to be strengthened.

By the method of integral equation, the second kind Fredholm’s integral equation is deduced to solve the interaction factors of pile-pile, pile-soil and soil-soil. Using the principle of superposition, the composite foundation is calculated. The validity of the present method has been verified through comparing with the experimental result. A parametric analysis is made to study the composite foundation settlement and the loads sharing by the individual pile and subsoil. The proposed method could be used to analyze the large composite foundation.

The man-made bedding is a new technique for building ocean dock and platform. By using self-developed discrete element method (DEM), the stability of single pile with embedded man-made bedding is simulated. The man-made bedding is composed of packed detritus and sand. The stability of pile is simulated for different heights of packed detritus under tide in the case of fixed height of packed sand respectively. The instability process of pile under infrequent tide is also simulated. The damping effects of seawater on pile and man-made bedding can be described by global damping. The results show that DEM can reflect the large deformation at the location of contact between pile and man-made bedding very well. The optimum height of whole man-made bedding can be determined from the results.

In order to study the effect of principal stress axes rotation induced by traffic loading on cyclic properties of soft clay in tests, one moving load and one train load are taken as examples to analyze the characteristics of principal stress axes rotation. On the base of loading properties of hollow cylinder apparatus, loading method to simulating the principal stress axes rotation in laboratory tests is given. The vertical dynamics stress can be simplified as sine wave with static deviator stress; and dynamic shear stress can be simplified as a sine wave. The phase difference between the two waves is . In order to simulate the character of principal stress difference changing continuously induced by traffic loading, the amplitudes of vertical stress and shear stress should be different. It is found that the angle of the maximum principal stress is between and or between and when vertical stress without stress reversal is exerted.

To improve the stability of traditional GM(1, 1) used in land subsidence prediction, the accumulating method is introduced to replace the least square method; and the accumulating method GM(1, 1) is established. By prediction of Shanghai land subsidence, it is shown that the condition number of matrix fall, stability of model is improved. Furthermore, the layer subsidence are predicted with the model stability judgement. The results show the trend of subsidence in Shanghai and give the help of subsidence prevention and curing.

The prediction and control of the ground surface settlement and deformation are ones of the most crucial problems in all environmental damages induced by metro tunneling excavation. The metro tunnels are usually excavated and constructed as double tube parallel tunnels; and the space between the double tunnels is generally short distance. The ground surface settlement and deformation induced by two staged tunneling is usually overlapped and is also hard to predict consequently. Based on the stochastic medium theory, the formula for predicting is modified; it is reality to predict the ground surface settlement, lateral displacement, lateral deformation, inclination and curvature induced by double tube parallel tunneling excavation; a new software system is developed to predict ground surface settlement and deformation induced by urban tunnel excavation. Two cases study for the double tube parallel tunneling projects are carried out to verify the validity and reliability of the proposed theoretical approaches and software system.

Based on the investigation data of the reservoir, the mechanical model of slope stability of the right bank dam shoulder is set up; and the computational formulas are deduced for calculating the cross-sectional area of each slip block. Then, slope stability analyses of both definite method and reliability method are carried out by using unbalance thrust force transfer method. The influences of the variability of shear strength parameters and geometric parameters of slip surfaces on slope stability are discussed in the reliability analysis. It is demonstrated that the variability of geometric parameters of slip surfaces has large effect on the reliability index and failure probability. Therefore, it is necessary to pay much attention to the variability of geometric parameters of slip surfaces as well as the variability of slip surface shear strength parameters.

Taking an engineering instance as background, the deformation characteristics and working mechanism of the cement flyash gravel (CFG) pile composite foundation are analysed with finite difference method; and the composite effect of the pile to work with soil and the effectiveness of cushion are also simulated. It is indicated that the bearing capacity of ground can be enhanced effectively through the CFG plies with some stiffness which are driven into the soil; the pile stress acts mainly from the top to the middle of the pile shaft; and the piles of which the lengths extended applicably can help to control the deformation of ground foundation; and the cushion is beneficial to adjust the stress distribution. The results can be for reference in similar projects.

In order to describe various uncertainties in slope stability analysis reasonably, stochastic and fuzzy factors should be considered simultaneously. Using L-R type fuzzy numbers to describe the mean values and variances of stochastic numbers, a novel fuzzy stochastic model for reliability analysis is proposed. For simplicity, the fuzzy stochastic reliability is calculated by transforming fuzzy numbers into a series of interval numbers via cut set theory. Based on the First-order Second-moment Method (FOSM), the fuzzy stochastic model is employed to Sweden Method and Bishop Method to calculate the fuzzy reliability factors of slope. It is demonstrated through examples that the proposed model is theoretically innovative and practically useful.

The seepage-stress coupled interaction of weak intercalated layer is the key factor affecting landslide stability. In order to estimate the integral stability of Dayeping landslide with weak intercalated layer, based on Biot consolidation differential equation, according to Goodman element form and introduced the interpenetration check idea of Desai element, 2D four nodes coupled thin-layer element is established by virtual displacement principle. An elastic-viscoplastic constitutive model is given to simulate the creep of landslide; and a corresponding finite element program is developed; then the program is verified by in-situ pore pressure testing data. At the same time, by using nonlinear FEM the seepage-stress coupling analyses of Dayeping landslide are carried out under normal water level and water level falling suddenly. The results indicate that the landslide is stable under normal water level, but under water level falling suddenly, landslide stability becomes worse because water level falling suddenly make the pore pressure, displacement, shear stress, plastic zone increase rapidly in middle-front part, and this may result in landslide middle-front part slipping along weak intercalated layer. In the end, rigid limit equilibrium method is used to verify coupled results; and the two conclusions are coincident. The analyses provide important theoretical basis for the comprehensive evaluation of Linxihe Hydropower Station construction feasibility, and the method establishing coupled element for analyzing weak intercalated layer provides helpful references for dealing with the stability of other landslides with weak intercalated layer.

Xiamen Triumph Avenue Project is a significant construction project in Fujian Province in 2005. This project consists of multi-overpass and two overlength tunnels. The tunnel from Lianqian to Wucunshan covers 3.7 km, which is the standard twin-tunnel two-way six-lane. The first stage project of Xiamen airport line located at Punan Industrial Zone contains multi-arch tunnel with width of 34 m buried in shallow depth. It passes through the bottom of 67 existing buildings and may cause great risks. The layer between the ground surface and the tunnel top is only 7?24 m of length and is bad in hydrology and geology. The top of the tunnel consists of mixed backfill soils and sedentary sub-clay layers, and the bottom consists of fully and strong weathered granites. The ground water level is high (part of the tunnel is about 20 m below sea-level). In order to guarantee the safety of existing ground surface structures, whole process grouting is put forward which aims at process control and process restoration. #104 and #105 buildings which are going to be removed are reserved as structures for experiment. The method of surface grouting and grouting from tunnel is adopted on these two buildings. According to the thought of whole process grouting, control standards for the existing structures are made. Laboratory experiment is made to compare the effect of different kinds of groutings. The effect and feature of grouting and consolidation on foundation, dynamic track grouting and restoration uplift after tunnel complete are studied. The relationship between grouting and uplift effect is also studied. The result of this experiment can provide experience and guidance for further construction of the first stage project of Xiamen airport line and the study can be adopted as reference for similar projects.

The geological environmental background of the north slope at 220 kV Yanjin substation is described; and a detailed analysis of deformation mechanism is made from topographic, lithology, geological and hydrogeological conditions, and external loading. The field investigation shows that the deformation of the slope is caused by a combined effect of internal factors, including unfavorable topographical, geological and hydro geological conditions inherent in the slope, and external factor, i.e., man-made filling. In order to define the calculating parameters, a set of consolidated drained (CD) tests, consolidated undrained (CU) tests, direct shear repeated direct shear tests and uniaxial compressive strength (UCS) tests are carried out. The stability of the slope is assessed using fast Lagrangian analysis of continua in 3 dimensions. The numerical modeling results show that the factor of safety (FOS) of the slope is 1.10 in the natural state, and reduces to 1.03 after filling, which is close to the critical state. After the site is reinforced with piles, the FOS is 1.27. Therefore, the slope is stable after reinforcement measures are taken.

Because of the particularity of size composition and sedimentary texture of glacial till, reliable parameters of strength and deformation aren't obtained by both laboratory test and in situ test. As a result, it is a difficult problem to choose proper strength parameters in engineering design and evaluation of glacial till all the time. Cellular automation method is adopted to simulate structure of glacial till and construct large-scale emulational trier. Afterward, triaxial numerical simulation tests are carried out on the emulational triers by using FLAC3D; and parameters of strength and deformation of glacial till are obtained based on mechanical formulas of general triaxial test. Thus a new method of strength test of rock mass and soil mass is presented; and a useful attempt to establish virtual geotechnical lab is made.