Research On Seismic Response Analysis Approach On Effective Stress And Physical State In Saturated Sand Mass

A new approach based on effective stress and physical states for analyzing the seismic response of saturated sand mass is considered as the center of this dissertation on the wide basis of discussing current analysis methods.Three points can be taken as the achievement of this research. The first one is the effective stress-physical states dynamic constitutive relationships established on the revealed dynamic stress-strain characteristics by systematical dynamic tri-axial tests under fully drained conditions of. constant spherical stress but cyclic deviator stress, of constant deviator stress but cyclic spherical stress, as well as of cyclic stress both spherical and deviator. These constitutive relationships are in the further combined with the framework of transient dynamics theory with a whole(static and dynamic) effective stress space divided into different zones by critical state line, phase transformation line and stress historical line.It can be used to consider the soil properties of non-linearity, hardening, shear dilatation-contraction, compression - swelling, and also the soil properties of stress path dependence and couplling of spherical stress to deviator stress. It is in the features of explicit physical conception and simplicity in soil characteristics description. These effective stress and physical states constitutive relationships consist of three patterns: ε_vp -ln(p/p_a)relation(linear), ε_vq-q/p relation(linear) and ε_sq -q relation(hyperbolic) with that the ε_sp - p relation is neglected because of the very smallvalue of esp. Their rationality is confirmed by the agreement of results calculated by using these relations with that tested. The second achievement of this research is the fundamentals of a 3-D dynamic consolidation with governing equations established on the basis of transient dynamics theory, characterized by drawing into it the effective stress and physical states dynamic constitutive relationships and couplling the dynamic response and dynamic consolidation, static stress and dynamic stress, pore water pressure generation, pore water pressure diffusion, dissipation with each other so that to simulate the true process of stress-strain response of soil mass and form a complete theoretical framework system of the seismic response analysis approach based on effective stress and physical states of soil mass. To solve the governing equations of this approach by using the FEM numerical calculation and develop a specific method and procedures for the calculation, and finally to delovep a new 3-D dynamic consolidation FEM calculation program inspected through seimic analysis of a saturated sand foundation make up the third achievement of this research. In this way, research of the dissertation carries the new approach taking the transient dynamics theory as basis to a new stage of its practice through amount of meticulous work in experimental, theoretical and calculation aspects.