非饱和土三维离散元计算中宏-细观参数关系探究

Insight into Relationships Between Macroscopic and Grain-scale Parameters in Calculating Three-dimensional Discrete Element of Unsaturated Soils

提出了一种建立非饱和土体宏-细观参数之间关系的方法,来建立在不同孔隙比和含水率等初始条件下非饱和土在不同应力路径下的离散元计算模型;通过编制离散元程序,基于接触粘结模型,对现有的PFC3D(Particle Flow Code in three dimensions)离散元程序进行改进,从而对在不同颗粒间粘结强度下的离散元试样进行一维固结的数值模拟试验来确定其结构屈服应力,并以结构屈服应力为桥梁建立颗粒间粘结强度随含水率变化的函数关系,最后建立能够反映真实非饱和土试样颗粒级配和在不同含水量下的离散元数值模型,为通过PFC3D等三维离散元软件研究非饱和土的基本力学特性提供思路.

The method that investigating the relationships between macroscopic and grain-scale parameters of unsaturated soils is proposed,which set up the calculation models of discrete element in different porosity ratio and moisture content under different stress path.By the discrete element program,the existing PFC3 D(particle flow code in three dimensions)was improved,and one-dimensional consolidation test of discrete element specimens in the different particles bond strength was carried out to determine the structure yield stress.In this paper,the relationship between intergranular bond strength and moisture content is established by means of structural yield stress,which can reflect the value of the actual sample size and the different water content and provide the idea to study the basic mechanical properties of unsaturated soil through PFC3 D.