基于离散元模型的土石混合体直剪试验分析

土石混合体是由高强度块石和低强度土体组成的一类特殊工程地质材料，其力学性质可通过直剪试验进行确定。本文针对土石混合体的细观材料特性，分别采用球形颗粒单元和非规则组合颗粒单元模拟土体和块石材料，对其在不同含石量和颗粒粘结强度下的直剪试验过程进行离散元分析。计算结果表明，土石混合体的抗剪强度随着含石量和粘结强度的增加而增加；通过不同法向应力下直剪试验的离散元分析，确定了不同含石量下土石混合体材料的内摩擦角和粘聚力。本文研究结果有助于进一步揭示土石混合体的抗剪强度特性。

ANALYSIS OF DIRECT SHEAR TEST OF SOIL-ROCK MIXTURE BASED ON DISCRETE ELEMENT MODEL

Soil-rock mixture is a special engineering geological material, which is composed with high strength rock and low strength soil. Direct shear test is an effective approach to investigate the mechanical characteristics of soil-rock mixture. In this paper, we adopt spherical elements to simulate soil material, and irregular overlapped clumps to simulate the rock rubble with Discrete Element Model (DEM). The shear strength of soil-rock mixture is obtained with direct shear tests based on DEM simulation under different rock contents and inter-particle bonding strengths. The results show that the shear strength of soil-rock mixture increases with increasing either of the rock content and the bonding strength. Moreover, the internal friction angle and the cohesive strength of soil-rock mixture are determined with DEM simulation under various rock contents. The results above will be benefit to reveal the shear strength of soil-rock mixture.