Under cyclic load, the major shortcoming–ratcheting is produced in Wolffersdorff hypoplastic constitutive model. For eliminating ratcheting, Wolffersdorff hypoplastic model is ameliorated based on intergranular strain tensor. The added parameters in ameliorated model are determined by optimization method. Under cyclic load of triaxial consolidation undrained condition, the mechanics features of sand are described by the ameliorated Wolffersdorff hypoplastic constitutive model. Preliminary result shows that with increasing times of cyclic load excess pore water pressure is increased gradually and effective stress is reduced gradually. When effective is reduced to zero, the liquefaction happens. So in many projects, excess pore water pressure must dissipate by means of some measures. The sand liquefaction under the dynamic load is avoided.

Based on frequency domain method, the seismic responses of the superstructure-pile foundation-soil system are studied taking the dynamic soil-structure interaction into consideration. For analyzing the earthquake response of cylindrical pile foundation, earthquake response analysis of three-dimensional system of pile foundation-soil-superstructure simplify two-dimensional question. The dynamic responses of the interaction system under EI-Centro ground motion excitation are evaluated by using secondary development of the large general finite analysis software Abaqus. It is shown that pile foundation is more anti-seismic and that pile foundation flexibility can improve the structural basic cycle. Based on a comprehensive assessment theory, soil-superstructure interaction problem under Earthquake is analyzed by second-level evaluation of comprehensive evaluation. By applying comprehensive evaluation method fuzzy theory model of soil-superstructure interaction is built. It is show that fuzzy mathematics method is appropriate for this kind of soil-superstructure interaction problem.

Wu-Bauer hypoplastic model may simulate cross-anisotropy of sand. The cross-anisotropy of the deposited sand is distinguished with the angle between deposited plane and direction of the principal stress in the Wu-Bauer hypoplastic model. The parameters considering cross-anisotropy in the model are determined by fitting experimental data with optimization. By virtue of intergranular strain tensor, the cross-anisotropy Wu-Bauer hypoplastic model is revised under dynamic load. Finally, the different deposited angle is computed by the revised model. It is shown that the revised Wu-Bauer hypoplastic model can simulate cross-anisotropy of sand and distinguish quantitatively strength and deformation of deposited sand in different loading direction under cyclic load.

Rainfall is one of the main factors that influence the stability of slope. Rainfall infiltration will cause soil saturation changing and further influence pore water pressure and medium permeability coefficient. Based on porous media saturation-unsaturated flow theory, the slope transient seepage field is simulated under the conditions of rainfall infiltration. It is shown that change of pore water pressure in slope soil lag behind relative changes in rainfall conditions. As the rainfall infiltrate, unsaturated zone in top half of slope become diminution, the soil suction and shear strength reduce, so stabilization of soil slope is reduced.

The deformation characteristic of granular material is important. It is important factor to analysis the bearing capacity and the thickness of granular material footings. There are many factors influence the deformation of granular material, such as material characteristic, content of water, degree of compaction, test method, etc. For analyzing size effect on the deformation characteristic of granular material, hypoplastic constitutive model considering void ratio is introduced. The influence of an initial void ratio, pressure and a mean grain diameter on the deformation is investigated by polar quantities: rotations, curvatures, couple stresses and a characteristic length. Thus, the influence of density and pressure on the initiation of shear bands can be investigated with a single set of constitutive constants.