粗粒土与结构接触面往返剪切试验的PFC2 D数值模拟

摘要

为研究土颗粒的细观，利用PFC2 D对粗粒土与结构接触面往返剪切试验进行数值模拟，研究接触面的剪胀特性与颗粒平移、旋转、破碎的关系及体应变可逆性和不可逆性规律。当不考虑颗粒破碎时，土体具有可逆性剪胀体应变；当考虑颗粒破碎时，土体具有不可逆性剪胀体应变。验证接触面体应变是由一个可逆性体应变分量与一个不可逆性体应变分量构成的。 PFC2 D位移场试验及类长形颗粒定向试验表明可逆性体应变主要由颗粒平移和颗粒自身旋转产生。对考虑颗粒破碎现象的黏结模型分析表明，不可逆性体应变主要由压密和破碎两种物态演化现象产生，颗粒破碎起主要作用。%In order to study the micro-scale of soil particles,the cyclic shear test of the graval-structure interface is simulated by PFC2D. The relationships between the dilatancy of the interface and the particle translation,rotation,breakage,and the rules of reversible and irreversible volume strain are studied. The soil has the volume strain of reversible dilatancy without considering particle breakage and the soil has the volume strain of irreversible dilatancy with considering particle breakage,which verifies that the volume strain of the interface is composed of a reversible volume strain component and an irreversible volume strain component. The PFC2D displacement field test and the elongated particle orientation test indicate that the reversible volume strain is mainly produced by particle translation and rotation. The analysis on the binding model considering particle breakage shows that the irreversible volume strain is mainly pro-duced by the evolution from particle compaction to particle breakage,where the particle breakage plays a main role.