On the basis of experimental data of triaxial compression in different conditions ,a stress –strain –time constitutive model was created through the learning procedure by using genetic algorithm which ran in the parallel computing environment .The predicted results which were obtained through the created model indicate that this model is well in accord with the constitutive model of diatomaceous soft rock .This method ,which creates a constitutive model by using genetic algorithm ,has a vigorous foreground in the rock and soil mechanics .It provides a new approach for the further research of constitutive models .

According to the deformation mechanism of rough interface ,a damage model for soil-structure interface was set up to simulate the mechanical characteristics of strain-softening and shear-dilatancy .The model can be expressed by only one formula with clarified physical meaning ,and has less parameters .The damage model was verified with the results of direct and simple shear test ,and the predicted result by the model is agreeable with test data .It is shown that the proposed damage model is reasonable and practical .

The uniaxial compression process of frozen soil was studied by computerized topography (CT) method .The characteristics of microstructure under different loading level are discussed for saturated and unsaturated frozen soil respectively .The feature of failure behavior is given out too .Finally ,the damage values resulted from newly born holes and cracks are calculated by using CT distinguishing model .

Rankine’s theory of earth pressure can not be directly employed to the case of cohesive backfill with an inclined surface .For this practical case ,it seems that no analytical solution is available .In this paper ,a theoretical solution of active and passive earth pressures of cohesive backfill with an inclined surface under surcharge was developed on the basis of the lower-bound theorem of limit analysis .First ,a statically-balanced stress field of the slope ground consisting of cohesive soils was construed from elasticity theory .Then it was enforced to not violate the Mohr-Coulomb yield condition .According to the lower-bound theorem of limit analysis ,two extreme values of lateral stress which respectively correspond to active and passive earth pressures were to be found and expressed in the superposition from .Based on the a number of numerical computations conducted for different combinations of the key parameters related to the problem ,the computed results useful for engineering practice were given in tabular and graphical forms .The effects of the main parameters on comprehensive coefficients of active and passive were discussed .

based on a series of model tests of piles, a new method for calculating single pile under lateral loading was presented .The popular constant ‘m’ value was related with pile head deflection by power function ,and this relationship was described by two factors :bm and k. With this relation introduced into the method ‘m’, the calculation results can consider the influence of the non-linear response of the single pile.

displacement computation of cutoff wall of second-phase cofferdam in Three Gorges project ,shows that the parameter of unloading modulus in Duncan-Chang nonlinear elastic E-ｕmodel has a fairish influence on precision of calculation .It is known by experimental data that the coefficient of loading modulus is dependent on component and density of every kind of soil ,and was obtained the empirical relation between loading modulus parameter and unloading modulus parameter from the experimental curve .So , unloading modulus parameter can be determined directly from loading modulus coefficient ,which coheres with practical circumstances in general .

based on the results of undrained plane strain compression test for shanghai’s typical clay ,the formation and development of shear band were observed ,and the mechanism of formation of shear band was studied by numerical simulation .

the experiment research on fundamental properties of a soft soil from a Haikou sea area ,Qingzhou Straits ,is carried out .The micro-mechanism of the poor engineering properties for the soft soil is preliminary analyzed from the aspects of mineral composition ,organic content, physicochemical properties and microstructure fabric characteristic ,which provides a help to understand the fundamental properties for marine soft soil further .

A new kind of practical soil constitutive model by combining Duncan-Chang inelastic constitutive model with the elastoplastic model adapting Drucker-Prager failure has been derived in order to overcome the classical elastoplastic model’s inability to cover the nonlinear behavior of soil before plastic yielding and unsuitability of normal Duncan-Chang model to the stress state approaching yielding or failure .Finally ,the numerical examples of practical problems have shown its feasibility and practicability.

An anisotropic model of sedimentary rocks is presented .the inherent anisotropy of this kind of material is described with an anisotropic parameter .A microstructure tensor and loading orientation are incorporated in the distribution function of anisotropic parameter and uniaxial compressive strength .A complete plasticity model describing the deformation process in anisotropic sedimentary rocks is given. Several triaxial tests are simulated with the anisotropic model .The results show that the inherent anisotropy in sedimentary rocks can be efficiently described with the model .

An experimental study on suction characteristics of loess in Yuncheng Region is conducted by using the method of tensiometer, thermal conductivity sensor ,etc..The soil-water characteristic curve of this kind of loess in drying procedure is obtained .This method is simpler than the method of pressure plate ;and the Fredlund and Xing Equation(1994) has been used to confirm the measured data .

The mathematical foundation and corresponding physical sense in large numbers of constitutive models of geotechnical material are important to understand and use them. The mathematical foundation and condition of all kinds of geotechnical constitutive models are pointed out。The keystone is whether or not there is unique potential field in which the stresses（strains）or their increments are its gradient vectors. The mathematical conditions include coaxiality of principal stresses and strains and their increments; symmetry of modulus matrix; rank of the matrix equal to 1; the curl of gradient vector equal to 0. The generalized potential theory is proposed in which unique potential function or 2-3 potential functions with linearly independent gradient vectors are used to determine the stress-strain relationship. The theory is provided large capacity and with wider application field for geotechnical material with complex mechanical properties.

A new mathematical soil model is developed for the one dimensional consolidation process. This model is used to explain the effects of secondary consolidation before the consolidation and to calculate the compression time curves. The results of analysis by new method give a reasonable engineering assessment of published experimental data.The purpose of the consolidation tests was to invesigate the influence of the maximum length of the drainage path and the time interval of the loading step on the rate of consolidation and the magnitude of compression for a remoulded normally consolidated clay exhibiting large secondary consolidation. The test results have been compared with the prediction for the consolidation process by the proposed method.

Base on the norm analysis of seismic signals and the structural system, the mixed optimal control index J is cited; and its physical implication is defined. The influence of soil-structure interaction(SSI) is considered. Considering the merits and defects of the H2 and control scheme, the controller is worked out by LMI convex optimal solution; the mixed control schemes that minimize the index J on condition that is given a definite value, are proposed.

In practice, pile-soil-cushion interaction of composite grounds with piles is not well considered in bearing capacity and settlement estimation. To solve it, based on the relation among pile-soil-cushion, the differential equations of settlements of piles and soil in large-area pile groups together with their solutions are presented. Compared to the results of finite element analysis, these solutions are quite accurate. This method greatly enhances the speed of calculation. The parameters used in this method are all routine soil parameters and are easily obtained through soil test. Also, the stress dependency of both the soil-pile limit friction and the compression modulus is taken into account in the proposed method. This method is practical and applicable to calculate pile-soil stress ratio and settlement of composite grounds with piles.

Grouting method was used for shoring and preventing seepage in blasted cavity soils,in order to solve the blasted cavity soils question of stability of stability and seepage rate and collapse.Comparison tests of the gravity grouting method,pressure grouting method, the pressure grouting method method with the waterproofing agent and without any support were done by using the critical water-cement ratio of 0.8:1.It is proved that the gravity grouting method can not meet the need;the pressure grouting method is feasible for shoring and preventing seepage in blasted cavity soils;and it is better with the watrproofing agent added.

In order to probe into seepage characteristics of rocks during their whole deformetion processes,the authors have carried out seepage tests on the specimens of granite which were taken from the high slope at the permanent shiptock of the Tree Gorges Project, and specimens of limestone which were taken from the high slope at the Wanjazhai Hydropower Station in Shanxi Province, under several surrounding pressures.The test results show that the rocks have obviously unlike seepage characteristics before and after destruction of rocks; and the permeability behavior of the rock during deformation has an osculatory correlation with the style of deformation destruction. On the basis of tests, the mechanism of seepage characteristics of complete stress-strain process is discussed further so as to offer the valuable support for the problem of coupling stress field and seepage field of jointed rocks in hydropower projects.

The centrifuge model tests were performed to investigate the ground settlements during tunnel excavation in sandy soil ground. A columnar rubber membrane tube was used to represent a tunnel. Compressed air was supplied to it to create a uniform pressure to support the surrounding soil. During centrifuge running, air pressure was gradually decreased to simulate the initial stress release; i.e., to simulate the excavating process. Through different combinations of test conditions including soil type, density, water content and tunnel embedment depth; the ground failure patterns and settlements were examined; the normalized P-S relationship were obtained and discussed..

The seepage pressure effects are comprehensive actions on cover-layer in the process of rain feeding karst groundwater, which includes load-increased effect of water, vertical-seepage effect, wetting-soft effect and obturation negative-pressure effect. And the seepage pressure mechanism is the primary mechanism of karst collapse in the center of cone of depression in continual pumping region. Based on the theory of М•М•Протодьяконов , the limit equilibrium theory and the karst collapse law in Zaozhuang city, this paper has established the mechanical model of surface-collapse phase and determined the height of equilibrium soil-hole in inter-collapse phase. Meanwhile, an evaluation of karst collapses in Zaozhuang city has been carried out by means of the formula and mechanical model. The result shows that the formula and mechanical model coincide with the forming mechanism of karst collapse in Zaozhuang city.

Parameter evaluation is one of key problems in numeric analysis considering non-homogeneous rockmass and complex surroundings as well as dynamic mechanic features of slope rockmass. Its accuracy has direct influence on accuracy and credibility of computational result. On the basis of parameter back analysis, excavation effect of permanent shiplock high slope of Three Gorges Project and further stress-strain state are analyzed. It provides foundation for deformation and stability analysis of operation stage of permanent ship lock.

It is the first time that using the newest specified loading equipment corresponding to the CT machine, the real-time computerized tomography testing of meso-damage propagation law of jointed rock sample with single crack under unloading confining pressure has been accomplished in rock mechanics fileld. Through CT scanning, the clear CT images are obtained to include the whole process of rock failure on unloading confining pressure from the crack development, penetration and fracture failure in the different stress states. It is clear that it is easy for failure phenomenon to happen suddenly in the process of unloading condition of jointed rock

According to the test data about flyash on chemical analysis ,grading test, compaction test, triaxial shearing test and compression test, the engineering traits of flyash ,such as compression trait and strength trait are studied. The factors influencing on engineering traits of flyash and its application as replace material in ground treatment, are also discussed.

A new rheology mechanism in according with the function of cohesion during the course of rheology for rock is expounded; a new 1-D constitutive model for viscoelastoplastic rock is set up, and the corresponding 1-D creep model and the corresponding 1-D laxity model are deduced. The creep model is used to simulate the curve of rock’s creep in the experiment. The model is verified by the experiment.

Using the special purpose loading equipment made by authors corresponding to CT machine ,the computerized tomography (CT) real-time testing of specimen’s failure with single fracture and hydraulic pressure under uniaxial compression has been made. The whole procession of specimen being compressed, new damage coming up and the failure process of hydraulic fracture of rock are simulated .At different axial pressure ,clear CT images and CT values of different parts are obtained .With studying the data of test , the threshold value of damage and damage propagation rate are defined; and some discussion of hydraulic pressure’s effect is made. The damage and fracture propagation law of jointed rock has been obtained from meso-scale and three dimensions.

A numerical iteration method for determining load-settlement relationship of a single pile is developed considering the pile-soil(or rock) interaction. The P-S curve of such a pile is obtained and can be used for calculating the load bearing capacity of the pile.Comparison between the results obtained by the proposed method and the measured data is made; and close agreement has been found. It is shown that the proposed method is theoretically reliable, simple in application and useful in practice.

Based on the existent status of pore water pressure,by using the effective stress principle of unsaturated soil,the extension of elasticplastsion of elastoplastio model of saturated soil to unsaturated soil is carried out;a modified Cam model which can account for unsaturated soil's gradually collapsibility is established.The model has few parameters and cam get them from water characteristic curve and saturated soil's test; it is applicable in practice.

On the basis of analyzing the coupling method of analytical solution for drainage hole and FEM[6,7], the improved analytical solution for drainage hole was proposed for six-side element and then coupled with FEM. An example of seepage with a drainage hole was calculated by the old and new methods respectively . By comparing the results, the improved method is illustrated to be more reasonable.

A method was presented for reasonably evaluating of bolts reinforcement of the shear strength of rock joints.The effective approaches to improve the bolts reinforcement efficiency are discussed by analyzing several important factors which have influences on the bolt reinfrocement efficiency.Therefore the defects of relevant analysis proposed before by many anthors have been inproved.

On the basis of the transferring matrix method,which is an explicit solution for acisymmetrice problem in layered elastic half space,the calculation method given in this paper can reduce the error,which is caused mainly by the integral variable ξ The terms can be divided into two kinds.One includes 1/ξ and the other does not.For different cases,different transferring matrixes;should be chosen the modificatory transferring matrix and the preliminary transferring matrix according to whether the term contains 1/ξ or not.

A series of stress path tests are carried out for undisturbed mucky clay samples from Hankou. The tests results indicate that there is a good hyperbolic connection between the axial strain and stress ratio R in those decreasing p path tests, then a normalized hyperbolic model of stress-strain is proposed for soils which undergo decreasing p path. Volume change behavior in drained tests and pore pressure characteristics in undrained tests are also described.