基于物态本构模型的土体动力反应分析方法

Approach of soil dynamic response analysis based on physical state constitutive relationship

通过对现有土体动力反应分析方法的分析,提出了新的有效应力物态地震反应分析方法。首先,建立了能够全面反应饱和土体的应力应变非线性、硬化性、剪切胀缩性和压密回胀性、应力路径相关性以及球应力和偏应力与变形的耦合性等主要特征的有效应力物态动本构关系。其次,以动力固结理论和瞬态动力学理论为基础,将该本构关系引入到以动力反应与动力固结相耦合、静应力和动应力变化相耦合,孔压产生、扩散和消散相耦合、能够较全面反映动力作用下土体应力应变反应的真实过程为特点的三维瞬态动力方程组,形成了饱和砂土体有效应力物态地震反应分析的完整理论体系。最后,开发了新的动力固结三维有限元分析程序,通过对一个饱和路基的计算和分析,不仅得到了合理的土体动力性状,而且验证了该分析方法与程序的正确性。

A new approach based on the effective stress and physical states for analyzing the seismic response of soil was emphasized as the center of this paper on the wide basis of discussing current analytic methods. The first one was the effective stress-physical state dynamic constitutive relationships established on the revealed dynamic stress-strain characteristics. It could be used to consider the soil properties of non-linearity, hardening, shear dilatation-contraction, compression-swelling, as well as the soil properties of stress path dependence and coupling of spherical stress to deviator stress. The second achievement of this research was the fundamentals of a 3-D dynamic consolidation with governing equations established on the basis of the transient dynamic theory, characterized by combining the effective stress and physical states dynamic constitutive relationships and coupling the dynamic response and dynamic consolidation, static stress and dynamic stress, generation, diffusion and dissipation of pore water pressure so as to simulate the actual process of stress-strain response of soil mass and form a complete theoretical framework system of the seismic response analysis approach based on the effective stress and physical states of soil mass. Finally, a new 3-D dynamic consolidation FEM calculation program was developed, and inspected through seismic analysis of a saturated road foundation, not only the reasonable soil properties were obtained, but also the validity of the proposed method and program were proved.