Based on the analysis of the compression, shear nonlinearity and dilatancy of sand and its complicated response under the complicated stress condition including the cyclic loading, rotation of principal stress axis and deflexion of stress path; three kinds of stress-strain relation are obtained. They are described by a relationship between effective mean normal stress and compressive volume strain, a relationship between deviatoric stress and deviatoric strain and a relationship between effective stress ratio and dilatancy strain ratio respectively. Through the increasing length in deviatoric strain path determined by the component in deviatoric strain space, the positive and negative dilatancy can be obtained under rotation of principal stress axis or deflexion of stress path. Developing the essential stress-strain relations under cyclic loading, a physical state dynamic constitutive model of sand is establisbed and related to its change in physical states.

In light of the surrounding rock mass of class V of Fenggang tunnel, a three-dimensional nonlinear simulation for it has been carried out. The cavity effect and the damage softening effect induced by excavating the tunnel in soft rock mass, have been presented. And the fitting of convergent deformation is effectively established by using the parameters softening method for plastic zone. Finally, the space effect, reinforcing effect as well as the optimizing construction scheme are also discussed; and the stability of the tunnel is demonstrated too.

Based on the energy conservation law and mechanical properties of rock, the physical cellular automat (PCA), a new model set up by authors to simulate the nonlinear evolution of rock failure, is developed; and the PCA model can be used to simulate the macroscopic mechanical behaviors of rock system caused by the compositive results of the simple reciprocity among the partial cells in the rock. Entitative influence on the constitutive relation of rock is studied by way of PCA; and micro-mechanism of elasticity, brittleness and plasticity of rock is profoundly revealed. The ideas and conclusions of the paper can be used as an important reference to numerical simulation of meso-mechanics and design of new composite materials.

The deformation monitoring data of the middle pier of the Three Gorges permanent shiplock reveals several interesting deformation phenomena. Conclusions and explanations are made concerning the phenomena, based on the finite element analysis and engineering geologic analysis. First, the fluctuation of the horizontal transformations can be attributed to the alternate excavation of the two neighboring shiplock rooms. In addition, the main reasons for the one-side-leaning phenomena in some places are the natural stress, which is not evenly distributed, and the presence of discontinuities. Lastly, the rockmass discontinuities result in the displacement breaks. A valuable reference for studying the ‘individual phenomena’ in geotechnical engineering is provided.

Based on Betti energy reciprocal theorem, initial flexibility tensor and damage evolution of rock mass subjected to seepage pressure are presented. And an elastic fracture-damage constitutive equation taking account of seepage pressure is also established. The concept of additional flexibility tensor is introduced to indicate the influence of seepage pressure on the mechanic characteristics of rock mass. The results obtained from a practical project show that the seepage pressure is of great importance to damage evolution when there is groundwater flow in fractured rock mass.

The collapse of surrounding rock mass of tunnels is affected by many factors; the identification of the collapse type is a very complicated nonlinear system identification and it can not be solved by traditional methods. The problem of complicated nonlinear system identification can be solved very well using neural network (NN) model. Considering the existing problems of the traditional NN model and traditional evolutionary neural network(ENN) model and combining the immune evolutionary programming (IEP) proposed by authors with NN, a new ENN model whose architecture and connection weights evolve simultaneously is proposed. Using this new ENN model, the problem to identify the collapse type of surrounding rock mass of tunnel is studied. The results of an example show that the performance of the new ENN is very well and it is a very good method to identify the collapse type of surrounding rock mass of tunnels.

The influence of confining pressure on the post-peak softening rule of soft rock has been researched. Based on the stress-strain curve of triaxial experiments, the softening law of physical property parameters is studied; and a post-peak softening numerical model is established by means of the technique of determining the equivalent cohesion and friction and the curve-fitting. At last, the numerical simulation based on the model approximately matches the triaxial experiments.

A new approach of classification of engineering rock based on the support vector machine is presented. The nonlinear mapping between rock classification and its conditions are learned from the finite samples and used to classify the rock. The precise results are acquired by using this approach.

For researching into the microstructural peculiarity of geomembrane and proceeding to the next step of evaluating the mechanism of seepage in microcosmic side, optical and electronic microscopes are used to analyze the microstructure of geomembrane. The difficulty is taking a series of pictures of geomembrane in definite condition and making picture processing. By analyzing geomembrane microstructure, it is indicated that the results from optical and electronic microscopes are combined; moreover, the structure impure particles and plasticity defects are the major factors, which make geomembrane damage.

A physical model has been established on quick sand of complete wells and at the bottom of semi-spherical wells for dyke foundations of double-layer structure, and the dynamic progress of quick sand based on critical hydraulic gradient is simulated in calculation examples by using the time-division stable flow theory. The concentrated permeation channel resulted from osmotic deformation in the dyke foundation will develop from the sand gushing opening along the vertical axis of the dyke, and keep on expanding in horizontal direction from the opening to the river bed, with increasing depth. The size of the channel depends on the flow and water level at the sand gushing opening, and in particular, maximum channel size is possible at low water level. A relief well can lower the head in its adjacent area, but at the same time increase the hydraulic gradient, thereby making it more likely to develop osmotic deformation. Therefore special attention should be paid to the design and construction of the reversed filter of the relief well, so that the soil body can be kept at the original position without causing osmotic deformation.

The solution of slip line for evaluating the ultimate load influenced by anisotropic damage is derived under plane strain condition. The field of slip line is drawn. Finally, the influence of anisotropic damage on bearing capacity of shallow foundation is studied. With isotropic consolidation clay, bearing capacity factor Nq reduces with the increase in damage accumulation, until it may be a minimum value.

A new method is put forward to analyze the stability of slopes; the action between the soil spencer is supposed to be pararrel to the bottom but does not equal. The safety factor can be got with the consideration of equilibrium conditions and the principle of strength failure. Examples show that it is a sensible and effective method of slope stability analysis.

The influences of confining pressure, end constraint, height of specimen and interface on networks of shear bands are investigated numerically. Firstly, some factors including height of specimen, confining pressure, temperature, axial strain and different numerical methods were discussed. Secondly, the FLAC 3D was used to simulate planar multiple shear bands and friction angle and cohesion force were dependent on plastic strain. The conditions, under which the multiple shear bands tend to form, were discussed. As end constraint is strong and confining pressure exists, the multiple shear bands appear in the center of specimen. For weak end constraint, the multiple shear bands form in the end of the rock specimen and numbers of shear bands increases with height of specimen. For large normal and tangential rigidity, shear bands can penetrate old fault and propagate along their inherent directions and the form of networks of shear bands is very apparent. The results obtained agree with many experimental tests and can be used to explain some phenomena of shear strain localization in seism.

Two problems of Tianjin pre-consolidation marine soft clay have been studied through large numbers of tests. One is the structure of soil; the other is elastoplastic model. The structural strength coefficient is led into for the first time, the relationship between microstructural quantitative parameters and mechanical parameters is established. A new kind of constitutive model is proposed to estimate the stress-strain relationship with the changes of structure and so as to offer a new channel for the structural model research and actual application of marine soft clay.

By analyzing of the results measured during construction of pile foundation, the magnitude, distribution and range of the excess pore water pressure caused by an installing pile in soil around the pile are discussed; and are compared with theoretical estimates. The excess pore water pressure at the interface of the pile and soil is discussed too.

A general shear strength formula of geotechnical slip surface and a general relation among failure principal stresses and a general relation between failure surface position and strength criterion under plane strain condition are derived theoretically. It provides theoretical basis for determining geotechnical slip surface and has a guiding significance for studying geotechnical strength criterion.

Most of the methods which used to estimate the initial ground stress are reviewed. A new approach integrating the theory of finite element method and theory of artificial neural network based on radial basis function (RBF-ANN) was suggested to simulated the initial ground stress. Over fitting could be avoided by using ANN-RBF during the back analysis process. The new approach based on the 3D-FEM integrated the advantage of other methods and took into account of the influence of diverse factors including fault on the initial ground stress. Therefore, back-analysis results are more reliability. Case study shows that the reasonability of initial ground stress simulated by using this approach. In addition, the faults have been considered in 3D-FEM model to evaluate the influence on the initial ground stress and it is helpful to understand the distributing law of initial ground stress.

A nonlinear viscoelastic model is introduced to describe the creep behaviors of soft soil. The model is used to analyze the damaged board of a bridge-pier. The finite element computation is used to make out the reason of the damaged board of a bridge-pier. The result of the computation shows that the lateral force caused by soft clay is the main reason of the damage of the board. The effect of the reinforcing measure was computed. A method to change the building step was advanced to solve the problem. The substitution of pile with shallow foundation was computed; and the feasibility of applying shallow foundations is also demonstrated.

An elastoplastic assumption is introduced in calculating passive soil resistance on retaining structure. The problem of determining inserting depth of retaining structure is solved by using elastic-resistance method. Comparing with practical engineering, theory obtained from this method is perfectly proved.

The settlenment rate of piletop is used to describe the bearing process of piles and the settlenment rate is taken as a fuzzy random variable considering the fuzziness and randomness of the failure of piles. The membership function of in the failure state is determined with fuzzy statistics method and the distribution parameter of is obtained with the probability statistics method. The calculation method for the reliability and the reliability index of pile foundation is derived and it is demonstrated through examples to be theoretically innovative and practically useful in the reliability analysis of the load bearing of pile foundation.

In the light of that the increase of bearing capacity of a single cemcnt soil pile is obvious as time goes on, an unequal time series grey forecasting model of GM(1,1) is established according to the grey theory; and a single cement soil pile’s bearing capacity is well forecasted by the established model. Through the comparative analysis of the observed data and forecasting date, the time effect law and change tendency of single pile’s bearing capacity are made clear. Finally, the suitable time is suggested to loading test of the cement soil pile.

A right angle plane coordinate system that is applicable to analyze the stability of soil slopes is set up. The integral formulae of the stability analysis are obtained based on the Sweden slip circular method. It has been verified and compared with Zhang Tianbao method. The integral method based on the principle of the simplified Bishop method is presented to analyze the stability of slopes. The integral formula of the safety factor is deduced. The numerical calculation and figure treatment are programmed. An engineering example is coted to prove the correctness of this method.

For axisymmetric Biot consolidation of columnar cross-isotropic soil-sample, there appears the series solution consists of an elasticity solution which meets inhomogeneous boundary conditions and a quasi-dynamic solution of seepage flow which meets homogenerous boundary. And through numerical example analysis, some Biot consolidation characters and Mandel-Cryer effect of columnar cross-isotropic soil-sample are investigated.

A comprehensive assessment method of stability of critical rock-block mass is presented. In this method, grey system theory, reliability theory and times series analysis are applied to assess the stability of critical rock-block mass. Taking the #V critical rock-block mass at Qingjiang Power Station for example, its stability is analyzed; and better results are got. The method is simple and practical, and it provides much rationally scientific basis for the design, excavation, construction, stability analysis, reinforcement and safety monitoring of critical rock-block mass in slope engineering.

A detailed investigation is carried out on the influence of water saturation in the reflection, transmission and horizontal and vertical motion at an interface between mainly water-saturated porous soil and ordinary elastic media induced by P wave. Theoretical formulation is developed for the computation of amplitudes of horizontal and vertical interface motion. Numerical results are given to illustrate the influence of saturation on the interface effect.

A similarity model is designed according to the type of bolts commonly used in coal mines and their grouted situation. To send out high frequency stress wave and meanwhile receive it on the top of bolt, an acceleration sensor with spring striking pin is invented. It is proved that the bolted length can be inspected accurately and the quality of a bolt can be evaluated by using the non-destructive inspection technique of high frequency stress wave. The rule to distinguish whether the quality of a kind of bolts is eligibility can also be found through express inspecting and drawing at random. It is confirmed by field tests that this method is economical and practical.

According to the character of bad geology surroundings and scarce basic information in process of underground engineering designs, the technology of information design is discussed and analyzed combining a tunnel project. A project-database information management system is designed and developed. With the offset data obtained by in-situ construction method monitoring, the mechanical feature parameters of surrounding rock are obtained with optimal back-analysis method. The displacement of surrounding rock is calculated and the stability of surrounding rock is analyzed during tunnel construction progress by three-dimensional nonlinear finite element method with these obtained mechanical feature parameters.

The method being used to measure the suction of unsaturated soil is based on the calibration of the suction of filter paper. This method was studied in China and abroad, but for homemade quantitative filter papers the calibration curves can just be used to lower suction. Based on the previous works we have made the calibration of filter paper suction at the higher suction. The calibration curves for the filter papers made in China or abroad are almost the same, which consists of two sections, one with larger slope and the other with smaller slope. We also found that the equation developed by van Genuchten is better to fit the calibration curve.

According to an exponential function describing the relation between friction around the pile and relative displacement of pile-soil，a constitutive model of interface is put forward and used as a means of studying pile-soil interaction with Goodman interface element。An elastically nonlinear constitutive model of concrete is employed to analyze stress-strain relationship of reinforced concrete under the axial load because of enough stress of reinforced concrete of the super-long pile。A compiled finite element program can solve layered soils and different characters of pile-soil interaction along the pile body caused by layered soils。According to the character of variational section of a case pile，it is considered as uniform section of pile with reasonable computing method assuring compute precision in the finite element program。Calculational results of the engineering case agree to statically loading testing results of the pile。

Optimization process technology of fuzzy information is used to predetermine the effective reinforcement depth of dynamic consolidation. The corresponding calculation program KFIDM is compiled; and its application shows that the method is more effective and practical than traditional methods.

The 25 test data of the composite foundations of CFG piles collected from all over the country are processed statistically according to reliability theory. The reliability indexes of the composite foundations of CFG piles is calculated by the non-dimensional calculation mode and the influence extent of each stochastic variable on the reliability index is also analyzed. For evaluating the reliability of the conventional empirical formula , some references may be provided.

The excavation and pit support are the problems that must be solved during reconstruction and extension of the subway stations of existing line built in 1974,which was part of line No.1 of Tianjin Metro system. Because of soft ground, pre-grouting is needed to reduce the displacement and settlement of the station box due to deep excavation and back filling, and also to control ground water ingress. These stations are right under the main streets and the heavy traffic in the streets makes the work very difficult. The possible construction operations to control station box and ground displacement and minimizing the effect due to reconstruction on the traffic are researched; some suggestions are given .

With the block theory and orthogonal design method, the type and geometrical characterstics and stability of random key block in underground power house of the Three Gorges project are analysed. It is showed that the depth of key block in rockmass is possible to have 7-8 m although the stability of random key block in the underground power house is better; and that the embedded length of system bolts shall be greater than 7 m so as to guarantee the stability of rockmass.

Based on track vibrating acceleration data measured from tunnels of Shanghai Metro Project, the numerical simulations by using 3D and 2D FEM are carried out in order to understand the dynamic response of overlap tunnels in close proximity to Nanpu Bridge Project due to the train’s vibrating load. The follwing conclusions are given: 1.mutual influences between the overlap tunnels are much greater than the parallel ones; 2. the longer the distance between the tunnels, the less the mutual influences; 3. for the tunnel structure design, the static soil pressure is the key load, and the additional stress induced by the train’s vibrating load is much smaller than the stress induced by the static load.

The application, feasibility and crisis of cement deep mixing piles are introduced. The mixing inhomogeneity and discontinuity along pile length in the present construction quality are pointed out. The reasons resulting in quality problem are analyzed as 3 aspects, i.e. severely delayed quality inspecting methods in the code, irrationality of construction techniques, disordered construction supervision. Then 3 kinds of countermeasures and 9 kinds of innovative approaches in construction techniques are put forward.

By analyzing the measurement data for Danjiashao Tunnel at unbalance pressure landslide section, the relationship between the bending moment of H-steel , the stress of the surrounding rock masses and the geological condition is obtained; which means that the surrounding rock masses stability can be forecasted by setting measurement apparatus so as to design the tunnel’s supporting measures reasonably.

The variation of pore water pressure around foundation pit induced by excavation and dewatering is discussed; and fitted curve is created based on in-situ measured data. The mechanism and process of variation of pore water pressure around foundation pit are also analyzed.

The deep fracture regularity of Pusiluogou left abutment slope at Jinping first stage hydropower station is comprehensively studied; and four deformation models of deep fracture are put forward； they are gentle shear and steep tension, gentle shear-tension belt, steep shear and gentle tension as well as tension respectively. The prime deformation ovctor points to Yalongjiang viver with certain angle, that shows the deep fracture is the result of slope unload, therefore the mechanism of the deep fracture is illustrated in some degree.

The controlling measures for ground surface settlement of three little distance parallel shallow embedded tunnels in weak surrounding rock have been studied. The results show that the different engineering measures have obvious influences upon the ground surface settlement,the surrounding rock pressure, and convergence displacement.

According to the occurring, expending and evolving process of the landslip, which has taken place in J contract segment # 3 slope at Wan-Liang expressway, the mechanisms of landslip under the excavating unloading condition in slow leaning stratum are deeply discussed; and the double face shear effect and joining move effect that lay in stratum rock slope landslip are put forward, which is very suitable to the result of model testing; and therefore a scientific basis for efficient controlling these types of landslips, is provided.

Based on basic concepts of stress relief and displacement relief in tunnel excavation process, a FEM simulation calculation for unloading under tunnel excavation is carried out. The effects of tunnel excavation modes on the displacement relief of strata are discussed. The calculation results may be used as a reference for selecting tunnel construction methods.

The advances of management for municipal solid waste landfills are reviewed systematically. The concepts of ecological landfills, including its practical meanings and tendency etc., are also introduced. Some new ideas and problems that should be studied particularly are also proposed.