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 .