颗粒土的亚塑性-塑性本构模拟

A MIXED HYPOPLASTICITY-CONVENTIONAL PLASTICITY FORMULATION FOR CONSTITUTIVE MODELLING OF GRANULAR SOILS

颗粒土在低应力区与高应力区的力学响应有较大的差别.低应力区的材料响应具有很强的密度依赖性,而在高应力区,则有显著的颗粒破碎效应.论文基于颗粒土压缩变形特性,将与颗粒破碎引起的土体压缩性的显著增大当作材料的塑性屈服,采用一个塑性势来描述.以亚塑性模型作为基础模型,描述低应力区的力学响应.两者结合建立了一个亚塑性-塑性本构模型框架,用于描述颗粒土在较宽广应力范围内的应力应变关系.

The mechanical behaviour of granular soils at a relatively higher stress level differs significantly from that at a lower stress level.The granular soil responses at the lower stress level exhibit strong density-dependency.As the stress in the material is elevated,the density effects become less significant while the particle crushing effects become more and more important.In this paper,based on the analysis of compression properties of granular soil,the additional irreversible volumetric deformation induced by particle crushing is regarded as plastic deformation,which is described with a plastic potential.By assuming that the density-dependent behavior of granular soils at lower stress level can bedescribed by a basic hypoplastic model,a mixed framework of hypoplastic-conventional plastic model is then formulated for modeling particle crushing effects at the elevated stress level.Such a model can be used for description of granular soil behavior in a broader stress range.