块石含量和空间分布对土石混合体抗剪强度影响的离散元分析  

DISCRETE ELEMENT ANALYSIS OF THE INFLUENCE OF ROCK CONTENT AND ROCK SPATIAL DISTRIBUTION ON SHEAR STRENGTH OF ROCK-SOIL MIXTURES

作　　者：严颖[1] 赵金凤[2] 季顺迎[2] 

机构地区：[1]大连交通大学土木与安全工程学院,大连116028 [2]大连理工大学工业装备结构分析国家重点实验室,大连116023

出　　处：《工程力学》2017年第6期146-156,共11页Engineering Mechanics

基　　金：国家重点基础研究发展规划项目(2010CB731502);国家自然科学基金项目(U1234209;11572067;11672072)

摘　　要：土石混合体的抗剪强度在很大程度上取决于其块石的含量、空间分布、形态等参数。该文采用球体单元模拟土颗粒,通过组合颗粒单元构造非规则形态的块石,对不同含石量和块石空间分布下土石混合体的直剪过程进行了离散元数值模拟。计算结果表明,在低含石量下,土石混合体的抗剪强度随含石量的增加而增加;在中含石量下,受块石空间分布的影响,其抗剪强度呈现很强的波动性;在高含石量下,其抗剪强度显著增强,波动性相对较小。抗剪强度在中高含石量下波动现象的细观机理是块石空间分布影响下的力链结构特性。当块石的空间分布使其形成较强力链结构时,抗剪强度较高;反之,块石间的力链结构不稳定,抗剪强度相对较低。以上研究有助于从细观尺度揭示土石混合体变形和剪切强度特性的内在机理。The shear strength of rock-soil mixture materials is affected by the content, spatial distribution and shape of rocks. In this study, soil particles are simulated by spheres, and irregularly-shaped rock particles are constructed by overlapped spherical particles. Direct shear tests are simulated with the discrete element method under various rock contents and spatial distributions of rocks. The shear strength of rock-soil mixture material increases with the rock contents under low rock contents, presents obvious fluctuation under medium rock contents, and increases significantly with less fluctuation under high rock contents. The fluctuation of shear strength under medium and high rock contents is attributed to the force chain distributions affected by the spatial distribution of rock particles. The rock-soil mixture has high shear strength if stable force chains are generated. On the contrary, it has low shear strength if weak force chains are produced in the mixture. This work can be helpful in revealing inherent mechanism on micro-scale of the deformation and shear strength characteristics of soil-rock mixtures.

关 键 词：土石混合体 直剪试验 离散元方法 含石量 块石分布 

分 类 号：TU43[建筑科学—岩土工程]