The phenomena of strain accumulation in the specimen when tested by graded loading is studied through two group of comparative experiments, and then the influence of this phenomena on the dynamic shear modulus and damping ratio of the soil is analyzed. It is pointed out that because of the accumulation of shear strain, the hysteresis loops gained by graded loading method will shift along the shear strain axis as soon as the load grade number increases, while at the same time , the shape character of those loops will keep unchanged. The method of how to deal with the original data produced by the graded loading test is discussed. According to the results of the comparative experiments, it is concluded that the shear strain accumulating under comparatively small amplitude loads does little with the dynamic shear modulus and the damp ratio gained by the large graded loading test later. Lastly, the signification of the graded loading test method and its application to the soil dynamics research are discussed.

The experimental tests of loose sands subjected undrained monotonic shearing with the relative density of 30 % are performed by using the soil static and dynamic universal triaxial and torsional shear apparatus which is newly developed in Dalian University of Technology. A series of tests are conducted for loose sand under complex stress conditions with different coefficient of intermediate principal stress, orientation of principal stress and mean principal stress. Based on the experimental results, the effects of coefficient of intermediate principal stresses on the friction angles at phase-transformation state (PTS) and peak stress state as well as effective stress paths are respectively examined. It is found that the coefficient of intermediate principal stress will play an important role in controlling the undrained shear strength parameters of loose sands while its effects on both effective stress paths and the variation patterns of the relation between stress and strain is relatively minor. The dependency of soil strength parameter on the coefficient of intermediate principal stress is illustrated theoretically by using the generalized double shear criterion and can agree well with the experimental data.

In order to investigate the creep behaviors of soft soil in Pearl River Delta, a series of laboratory drained and undrained triaxial creep tests were performed. The test results show that in drained condition, soft soil has large initial deformation but small creep deformation. While in undrained condition, creep effect is significant. It indicates that enhancing the drainage ability of soft soil foundation can reduce the probability of creep rupture. By introducing Singh-Mitchell creep equation, the drained and undrained creep models of soft soil are proposed, in which exponential function is adopted for stress-strain relationship and power function for strain-time relationship. Predicted results are in good agreement with the experimental results. The values of model parameters change a lot with the variation of drainage condition, which results from the dependence of strain-time and stress-strain relationships on drainage condition.

To study the effect of vibration frequency on soil dynamic characteristics, firstly the related research outcomes are reviewed, then the dynamic triaxial tests which used core material of one rockfill dam were performed. The results of dynamic intensity tests show that with the increasing of vibration frequency f, dynamic intensity increases when f equals to 0.1－4 Hz; and with the increasing of f, dynamic porewater pressure ratio increases during f equals to 0.1－1.0 Hz while decreases during f equals to 1.0－6.0 Hz. Under the sustaining operation of higher frequency, there are phenomena of sample sopping up and dynamic porewater pressure declining. This means it hasn’t enough time for dynamic porewater pressure to climb and extend when f is much higher. And the results of dynamic modulus and damping ratio tests show that the lower the vibration frequency acting on the sample, the more sufficiently dynamic deformation could develop; both dynamic modulus Ed and damping ratio D increase with vibration frequency.

According to a lot of field tests and numerical efforts, the spatial deformation pattern of the top beam and pile is deduced for the anchored pile supporting system; and the expression of the potential energy is derived for the total supporting system. Based on the principle of minimum potential energy, a new analytic solution to determining the maximum displacement of the pile head is derived; and the effects of the retaining structural parameters on the displacement mentioned above are discussed. Results show that the maximum displacement of the pile head increases with the increase of the surcharge, the depth coefficient of the excavation and the spacing of the pile; but decreases with the increase of the soil anchor’s stiffness. When the excavation length increases to a critical length, the maximum displacement will approach the maximum value. In addition, the point of application of the soil anchor has a critical position. Finally, the result obtained from the proposed approach is compared with field tests and elastic resistance method.

The shaft friction can be improved greatly by base grouting, and the increment is the major part of ultimate bearing capacity increment of the overlength large diameter pile. There is a weak layer between a pile and the soil around it, so the grout always flows upward along the weak layer, squeezing the soil to a larger diameter and improving the shaft friction. According to the results of the self-balanced static load testing method, the SPT test and the CT scanning test of a project with overlength large diameter piles, the strength of soils in a large range above pile- bases was improved and the shaft friction was increased 12.39 %-52.87 %, the ratios of shaft friction in the increment of ultimate bearing capacities was 56 %-88 %.

It is shown that the excessive support pressure, deflexion of shield, the friction between shield and soil，and the big grouting pressure will induce the compacting effects during pipe jacking construction. In addition, the heaving process will reduce the total magnitude and widths of the surface settlement troughs after the construction completion. The soil is assumed as a uniform line elasticity material and the initial stress field of the soil is considered. Through the simulation of soil-compacting process by applying an outward elliptic radial displacement to the surrounding soil of shield, the approximate analytical solution of soil displacement fields in half space is obtained in small strains. Considering the spatial effects, the modified calculation formula is also presented. Furthermore, the calculation results from the modified formula are compared with field data. The maximum of surface upheaval is at both sides of axes. The calculated values are a little bigger due to hard surface of ground; while under the hard surface, they are in accordance with the measured values.

The rock mass of permanent shiplock high rock slope of the Three Gorges Project(TGP) has marked characteristics of unloading and relaxation. Kinds of methods such as geological investigation, sonic velocity test, monitor of deformation, in-situ test of elasticity modulus of rock mass, test of rock permeability, kinescope in hole, test of elasticity modulus of rock mass in hole, etc., have been applied to studying the characteristics. The study shows that the rock mass of the slope can be divided into three zones, strong-unloading zone, middling-unloading zone and slight-unloading zone. The degeneration of properties of rock mass in strong-unloading zone and middling-unloading zone is notable，while degeneration of properties of slight-unloading rock mass is not obvious. The structure and properties of the rock in unloading zone do not alert obviously; but the unloading causes the growth of the joints’ length and width. The deformation of rock mass of the slope mainly depends on the deformation of joints and elastic deformation of rock block, which is affected by excavation. The reinforcement cables have obvious effect on confining deformation of joints.

It has great important application value to study the relations between suction and moisture of unsaturated soil for its deformation and intensity. With the unsaturated triaxial equipment for expansive soil test, we analyze systematicially the multi-factors such as the components of mineral, the structure of hole, the stress state of soil and the stress history etc., which affect soil-water characteristic curve (SWCC). Especially the components of mineral and the structure of hole are primary influential factors. Based on the measurement of matric suction indoor and outdoor, we think over synthetically the effect of multi-factors to fit and compare SWCC, also we build the model of power function. And according to SWCC, the otherness is obvious in the curve of dry-damp circulation indoor and not obvious in the curve outdoor, which is similar to the welter curve indoor. The permeability and shear strength etc. of unsaturated expansive soil can be calculated by combining the curve outdoor with welter curve, which has great superiority in solving problems of geotechnical mechanics.

The explosive energy of charge in rock is composed of shock wave energy and gaseous explosive energy. Analysis of the distribution of explosive energy can help to improve the blasting effect and blasting performance. During coupling column blasting, the features of deformation and destruction of rock by shock wave, the explosion of cavity by detonation gas, and moving of cracks by the detonation gas with considering advance damage are analyzed. The result calculated for several rocks shows that the shock wave energy consumed makes up about 40% of the total energy of the charge. The energy consumption in the course of the cavity and main cracks expansion accounts for about 23% of the total blasting energy. The spare energy among which most is consumed to increase the amount of cracks is lost.

Landfill is a prevalent method for wastewater sludge disposal. Laboratory tests were conducted to study engineering property of sludge solidified by fly ash, lime and silty clay of varied ratios. The experiment results revealed that the strength of solidified sludge was as high as it is required for landfill; and permeability was improved significantly. Using freeze-drying technology and scanning electron microscope (SEM), the microstructure of solidified sludge is studied. It is found that the compactness of sludge was improved after solidification, which is an important reason for strength improvement. Applying theory of fractal geometry, quantitative analysis is carried out on the SEM images. The analysis reveals a considerable positive correlation between fractal dimension and strength.

Simplified method of ground settlement under negative pressure is studied, which the deformation mechanism under vacuum preloading is considered. Observation of settlement for vacuum preloading engineering shows that the practical settlement is smaller than the predicted one based on the National Code of China. The settlement correction factors for vacuum preloading and vacuum combined surcharging preloading are established based on theoretical derivation. It is concluded that the scope of ground settlement correction factor ms may be 0.55 to 1.20 for vacuum preload engineering; and 0.70 to 1.30 for vacuum combined surcharge preloading with layer wise summation method .

Based on the generalized Darcy’s Law which can describe the anisotropy of infiltration tensors and the relative permeable degree theory related to relevant fundamental seepage theory of a fractural rock mass, 3-D nonlinear finite element method was applied to simulate the process of three dimensional saturated-unsaturated and unsteady percolation diffusion in the high slope of the Three Gorges Project(TGP) permanent shiplock during continuous rainfall. The distribution of infiltration fields in the slope during continuous rainfall and the maximum value of the external water pressure acting on the concrete lining wall were reached in the different typical rainfall time. The authors can evaluate further the influence of the rainfall infiltration on stability and safety of the lining wall of TGP ship lock. Results can demonstrate that the concrete lining wall of TGP shiplock chambers has more larger safety, and the drainage system designed in the TGP ship lock slope is in good conditions, the influence of rainfall on the external water pressure will be small especially very strong rainfall continuous rainfall.

The vibration caused by the pile’s dynamic driving may result in damage to the structure near the site. A vibration monitoring has been completed in a power plant project where prefabricated piles are driven dynamically. Based on the monitoring data, the relationship between the depth of the pile’s tip in the soil and the peak velocity of vibration on the ground has been established; and the property of the soil at the pile’s tip is thought to be the main factor for the vibration. In addition, the vibration on the ground is related to the character of elastic waves, thus the decay laws are different at vicinity and there far from the pile. Moreover, the damping ditch near the object to be protected is more effective to reduce the magnitude of vibration on account of the epicentre being in the deep soil.

Land subsidence caused by groundwater exploitation seriously threatens normal employment and structure safety of buildings, so it is of significance that studying predicting method of land subsidence. Because of the difficulty of the constitutive model and the parameters of soil, and it is not perfect that the land subsidence is computed adopting Biot’s consolidation theory. In the paper, adopting combining methods both mechanics reasoning and statistic mathematics, sets up space-time predicting model research of surface subsidence caused by groundwater exploitation. Firstly, by means of Terzaghi’s consolidation differential equation, the semi-experience predicting model of depicting surface subsidence’s time effect is founded. Secondly, on the basis of analyzing the distribution laws of surface subsidence caused by groundwater exploitation, the space distribution characteristic of surface subsidence caused by groundwater exploitation is studied through the stochastic medium theory. Thirdly, synthetically analyzing the time effect and space distribution characteristics of surface subsidence caused by groundwater exploitation, the time-space predicting model of surface subsidence caused by groundwater exploitation is established. The predicting model totally needs 4 parameters when it finishes prediction. The method of parameters’ computation is introduced. Lastly, the time-space laws of surface subsidence caused by single well’s exploitation is computed and predicted with the predicting model. The research shows that the predicting model can nicely reflect the time and space characteristics of land subsidence caused by groundwater exploitation, and can expediently and rapidly predict land subsidence; and provides theoretical basis for prevention and control of surface subsidence caused by groundwater exploitation.

Hydro-mechanical(HM)coupling refers to the physical interaction between hydraulic and mechanical processes in rock mass. Understanding coupled mechanism is the foundation and key problem in HM coupling analysis. As a matter of fact, the coupled mechanism is determined by the behavior of rock mass structure. Based on analyzing HM coupling processes, the conceptual HM coupled models are proposed according to basic structure of rock mass and concept of representative element volume(REV). And than a multiple fracture media network fully coupled model of HM coupling is presented assuming REVS of fractured media without overlapping REV. Subsequently, a finite element formation of fully coupled HM model is presented to solve the mathematical model. The model and the formations will be applied to developing the program and software for HM coupling analysis. Numerical simulations program and validations of some samples are the subjects of ongoing research.

Several experimentation parameters which for evaluating soil indexes were obtained based on the flat dilatometer test of calcareous soil in shallow water. The reasons of the calcareous soil density at surface layer in shallow water is bigger than that of deep-sited soil are not only the wave cycle dynamic loading, but also because calcareous soil were made of coral reef cementation material; and it has big pore and relax deposit material. So the flat dilatometer pressure is obviously different between surface layer calcareous soil and that of deep-sited soil. Also it has preferable correlativity between flat dilatometer test results and on-site standard penetration test results. Liquefaction estimation of calcareous soil in shallow water under different earthquake intensity can be obtained utilizing Seed simplified equation which is fit for calculating under-water mean dynamic stress ratio.

Based on the overall temperature monitoring for frozen soil embankment with riprap slope protection and without riprap slope protection in Qingshuihe test section of Qinghai-Tibet Railway, the ground temperature, accumulated temperature and the maximum thawing depth variation in temperature field of these two kinds of embankments were analyzed. It is shown that the experimental embankment with riprap protection has better effect for its decreasing temperature, lowering minus accumulated temperature and lifting maximum thawing depth than that of the embankment without engineering measures. Therefore, the riprap slope protection embankment, as a positive frozen soil protection measure for its effectively decreasing ground temperature and being advantageous for slope surface protection, could be conveniently used not only for construction, but also for the future maintenance.

It is advantageous to know how much rainwater decreases or evaporation increases the stability of a soil slope. Numerical model was used to quantify the effect of rainwater and evaporation on the stability of a case slope. With raining model and evaporation model, unsaturated-unsteady seepage analysis was used to calculate pore pressure of the case slope, and Bishop Equilibrium balance method with total cohesion was used to calculate the stability factor of the case slope. Relationships between the pore pressure and time, between the safety of stability and time were obtained. Results show that changes in slope stability and pore pressure lag behind the change of weather; infiltration and evaporation affect the stability of shallow slip surface greatly, the stability of deep slip surface relatively little; in the process of rain, the critical slip surface changes from deep surface to relative shallow surface, in the process of evaporation, the situation is opposite.

It is very important for the tunnel lining to determine the earth covering thickness as the rising force when the shield tunnel machine crosses over the ground base under rivers, lakes the sea, and so on. The authors bring forward a new method to calculate the earth covering thickness of the tunnel lining .The new method takes into account of the shearing strength of the soil that can resist the rising force, while the conventional method doesn’t consider that. The new method is more practical than the conventional method according to the computation in the case study. Finally, the authors analyze the stress and strain in the shallow earth covering by FEM; the result proves that the new method is more reasonable.

Based on the meachnical behaviors of representative soil layer in Shanghai, several computation profiles with different soil layer constructions are built. An effective-stress procedure, in which the bounding surface hypoplasticity model and Biot consolidation formulation are coupled, is used to analyze the effect of soil layer constructions on liquefaction of sandy soil. The results show: the thickness of covering soil layer increases, peak pore pressure ratio of sandy soil decreases; when it is softer, shear stress of sandy soil increases firstly, then decreases; but harder, it increases continuously. The deeper underlying soil layer is, the smaller peak pore pressure ratio and the more shear stress of sandy soil is; both are not obvious. But, if softer, the peak pore pressure ratio of sandy soil changes more sharply.

Mechanism of settlement of ramp loading roadbed on soft ground is analyzed; and proof of settlement－time curve appearing S-shape is conducted directly based on consolidation degree of one-dimension soil consolidation theory. Mathematical analyses of Gompertz, logistic, Weibull growth model that appearing S-shape are conducted. Although Gompertz, logistic growth models are adopted extensively to predict settlement of ramp loading roadbed, they have deficiencies such as: (1)neglecting loading velocity; (2)neglecting construction art; (3) relative constant ratio of settlement at inflection point to ultimate settlement. Good usability of Weibull growth model is pointed out. Finally, suggests on prediction of soft roadbed settlement are proposed.

The back analysis in geotechnical engineering is a typical complicated nonlinear function optimization problem. To solve this problem, the global optimization algorithm is a very good method. But for the using FEM for many times in its process, the efficiency of this algorithm is low. In order to overcome the defect of those optimization methods, a new algorithm, particle swarm optimization(PSO), is proposed. Combining this algorithm with FEM, a new back analysis algorithm is proposed. Through a simple example, the proposed algorithm is verified; and the results show that this new algorithm is a very good back analysis method and its efficiency is very good.

The application of grey theory to data processing of fast load test is discussed. According to the grey theory, the author attempts to predict both t-s and P-S curves of the test and obtain the similar settlement which traditionally gained by slow load test. A VB program has been worked out. The contrast between the predicted settlement of an engineering example and the real settlement shows that the prediction of two curves made by grey theory is feasible. The precisions of two kinds of GM(1,1) model used for long distance prediction are estimated; and a conclusion is drawn that the extrapolation of P-S curve more than two or three grades is not accurate enough. The model must be modified when it is used to do long-distance extrapolation.

Three centrifugal model tests, i.e., unreinforced embankment, gauze reinforced embankment, and dacron reinforced embankment, are performed to study the behaviour of embankments on soft clay. Based on these tests, the distributions of the horizontal displacement and vertical displacement as well as the dissipation of the excess pore pressure in the clay foundation are obtained. The reinforcement mechanism of the geotexile is subsequently investigated, with particular emphasis on the effects of the reinforcement strength on the deformation and stability of the subsoil. Centrifuge test results show that the reinforcement can reduce both the settlement and the lateral displacement of the clay foundation, therefore contribute to the improvement the global stability. On the other hand, to guarantee the effectiveness of the reinforcement, the strength and modulus of the geotexile and those of the soil-geotexile interface should be comparable with each other.

Parallel computing is becoming the strong trend of solving large scale geotechnical problems. A parallel preconditioned conjugate gradient iterative algorithm for finite element problems with coarse-mesh/fine-mesh formulation is discussed. An efficient preconditioner is derived from the multigrid stiffness matrix. The algorithm is implemented on a workstation cluster. Numerical example of solution of soils after the dynamic compaction is presented and the parallel performance is analyzed. The results show high speedup and efficiency. The algorithm is efficient for parallel computing.

For the purpose of using GPS to monitor land subsidence for engineering technician, the theory of relative position by static difference global positioning system was described in detail. The method of monitoring large-scale land subsidence by difference global positioning system and the cause of bringing influence on the position accuracy of DGPS were introduced. The result indicated that the application of difference GPS to measure large-scale land subsidence has become an efficiently and accurately measuring method.

Based on the overcore method used in measuring initial geostress of rockmass and the borehole deformeter 36-2, a new twelve components borehole deformeter is devised. Compared with the former 36-2 borehole deformeter, which has only four radial deforming measurement elements, the new type has eight more axial elements. Its sensitivity and accuracy is each 0.0001mm and 2‰. A great number of calibration tests in laboratory manifest its sensitivity for stress measurement will reach 0.028MPa (while E=30Gpa). The deviation between true stress and measured stress is not greater than 10%.Using the twelve components late-model borehole deformation gauge, you will obtain three-dimensional stress (or total stress) state of one point only by once overcore test. This test equipment successfully overcomes the disadvantage of measuring three-dimensional geostress with the traditional thrice overcore test; and it enables remarkable economic benefit, convenient operation and higher reliability.

Some common problems such as system architecture, interfaces, database design and data structures during developing monitoring software system for hydraulic structures are discussed. Seven property objects were proposed to describe the complicated relations between hydraulic structures and monitoring instruments and between hydraulic structures themselves. Database design and data structures are given for those objects. And several data structure problems of monitoring data process, software robust, resetting initial values and sensors replacement are discussed also.

3D geoscience modeling is the key technique issue to the visualization of 3D geological data using GIS. Based on MAPGIS-TDE, the software system “3D geological modeling and visualization” is designed and established. MAPGIS-TDE, which is a powerful toolkit for 3D visualization, has a hierarchical structure composed of the kernel module of MAPGIS, the basal platform of MAPGIS-TDE, the construction platform of MAPGIS-TDE and the application system of MAPGIS-TDE. 3D geological modeling and visualization system has five functional modules as data management, 2D analysis, cross-sections processing, geometry modeling and property modeling. By integrating geographical database, areal geology database, engineering geology database, hydrological geology database, physical geology database, geochemistry database with 3D geological modeling, the system realize such functions as data management, 3D geological modeling and the visualization of 3D geological model. It is a visualization platform that assists the design and analysis for the geologists and the technologists.

On the utilization of the underground space with major projects, digital mapping based on the secondary development of MAPGIS by C++ Build connected with automatic drawing of histograms and profiles has important significance. By combined with the development of underground environmental information system of Water Supply Reconstruction Project from Dongjiang to Shenzhen in China’s Guangdong Province, China, the function design of automatic digital mapping module and data searching methods as well as automatic drawing methods of histograms and profiles are emphatically introduced. Data searching is emphasized on data organization form and synergistically searching way on multi-database; histogram drawing is developed two ways i.e. fixed table drawing and dynamic data filling; profile drawing is focused on another two ways i.e. elastic-liked realization method of profile lines and data calculation methods of profile data etc. In the application of digital mapping methods to a major project, Water Supply Reconstruction Project from Dongjiang to Shenzhen, the results show that the methods have some advantages such as high automatic extent, large efficiency and high accuracy and also has a better correcting capability. The research has a great value for the development of design and realization of digital mapping in engineering fields.

On the basis of the Ground Penetrating Radar detection of badger caves in embankment at Huaishu River, the structural characteristic of badger cave is analyzed; and the representative radar image characteristic is put forward. Then, the locations, depths and direction of badger cave channels are deduced for the cave remedy reference. The detecting results indicate that the GPR has the advantages of device portability, low site requirement and easy of adding detecting lines at various directions; and it is a very effective detecting device for shallow cave channels.

Based on the observation and research of the umbrella-shaped self-expanding anchor excavated in-situ after its application in foundation pit supporting system, according to monitoring data with and without this kind of anchor, its characters of expanded section and effect in application after grouting have been analyzed. And its quality control method is put forward.The results show this kind of anchor can form expanded section with cement and steel in the earth,so the displacements of the anchored thing can be effectively controlled..

Application of a surcharge load to soft soil ground results in immediate undrained lateral soil movement away from the load and induces additional stress into the adjacent ground; problems involving the respond of soft ground to surcharge have been the topic of much recent research. Based on the engineering application which uses the synthetic method of stress isolation and ground reinforcement to handle soft ground problem induce by the adjacent surcharge load, this paper employs the PLAXIS to analyze the stress distribution and deformation of ground; reasonable agreement between the result and the observing data, is found.

This paper mainly introduces the test results of an overlength drilling pile with base post grouting technique, including self-balanced loading test and coring test. According to tests, the grouting cement can rise up to 15 m from pile tip under the geological and construction conditions, but requires much time to reach its design strength and distributes non-uniformly around pile tip. The standard penetration tests (SPT) show the number of SPT after grouting is more than that of before grouting. The self-balanced test results indicate that the bearing capacity of the test pile after grouting is 1.5 times of that of before grouting. Compared with non-grouted piles, the base post-grouted piles obviously improve the bearing capacity and load transfer behavior.