含有液体的多孔介质在强动荷载作用下的力学行为

Based on the Biot theory for simulating coupled hydro-dynamic behavior in saturatedunsaturated.porous media, instability and dispersivity of wave propagation in the media are.analyzed. Stationary discontinuity and flutter instability of wave propagation in saturated.poro-elastoplastic media are further analyzed for the plane strain problems. The critical conditions.of stationary discontinuity and flutter instability occurring in wave propagation are given..Uniqueness and localization in saturated porous media are analytically and numerically.investigated. To consider the impulse nature of impact loads, a time-discontinuous Galerkin finite.element method for dynamics and wave propagation in saturated poro-elastoplastic media is.presented in order to properly capture discontinuities or sharp gradients of the solution due to.propagating impulsive waves in space, to filter out the effects of spurious high modes and to.control spurious numerical oscillation. In addition, a non-linear mixed finite element for.dynamic-seepage analysis in saturated poro-elastoplastic media in the frame of the Biot theory is.proposed. The proposed element is capable of modelling progressive failure characterized by.strain localization due to strain softening in dynamic conditions at large strain with high.performance..The wave equations to govern stress wave propagation in orthotropic saturated porous.media are derived on the basis of Biot’ theory. The expressions for the wave speeds and.attenuation coefficients and characteristic equations of stress waves are given. The influences.of the fluid viscosity and anisotropy of the solid skeleton on the propagation characters of the.国家自然科学基金资助项目结题报告.4.Rayleigh wave are discussed in detail. The characteristic differential equations and compatibility.relations along bicharacteristics are deduced and the analytical expressions for wave surfaces are.obtained. Based on these work, a new three-dimensional two-phase model is proposed from the.view of the meso-mechanics. The numerical results show that this model can reflect the influence.of the meso-characteristics of media, such as the pore shapes and distribution etc., on the.propagation characteristics of main waves..The liquefaction and the densification of saturated sands are studied by means of the.combination of laboratorial experiments and theoretical analysis. The main aim is to reveal the.damage and pore fluid flow phenomena occurring in saturated sands subjected to impact loading.with high intensity. The experimental devices and the pressure measuring system driven by impact.and hydrostatic pressures are established. It is observed that inhomogeneous deformations and.pore fluid flows, i.e. longitudinal drainage pathways and transverse cracks in the sand sample will.develop as it is subjected to intensive impact loads. The systematical experiments for quantitative.description of constitutive relation of saturated sands with laterally constrains under cyclic.compressive loading are carried out. The compressive effect of the gravity on consolidated sand is.considered, the time required for full consolidation and the dissipation velocity of pore-water are.obtained.

基于多孔多相变介质的流固和流流耦合模型，以饱和砂土为典型介质，研究强动荷载作用下介质固相和液相中所产生的波系及以应变局部化为特征的破坏过程；介质中振动，液化，非均破坏与流动以及密实等效应，提示其控制因素，转化条件及后效。发展数值模型定量估计介质中固相和液相的耦合响应。有助于地质灾害和工程事故的防治与爆破新技术的开发。.