基于离散元理论的粗粒土三轴试验细观模拟

基于三维离散元颗粒流理论,综合考虑颗粒间黏结力,确定颗粒接触本构关系,建立有黏结材料工程性质的数值仿真模型,实现对粗粒土工程力学特性的模拟。根据某粗粒土室内三轴试验结果和大量数值试验,对颗粒流数值模型进行标定,精确再现室内试验的加载曲线。基于标定后的颗粒流模型,针对不同的试样加载过程,分析不同应力路径下的力学响应。通过对颗粒流试样细观参数的进一步分析,研究试样的颗粒间的摩擦系数、细观连接强度以及孔隙率对宏观力学特性的影响。揭示模型细观参数对宏观力学响应的影响,研究结果表明：通过控制细观参数可实现对宏观力学响应的调整,并据此给出细观参数选取的若干建议,为今后的颗粒流模拟试验提供参考。

Meso-mechanical simulation study on triaxial test of coarse-grained soil based on DEM

A simulation model of bonded material was established based on the theory of particle flow code in 3D（ PFC3D）. The cohesion force of particles was taken into account when determining the constitutive relations of particles. The PFC model was demarcated according to the results of the triaxial tests and massive numerical tests,which demonstrated the laboratory test accurately. Research on different stress paths was carried out on the basis of the demarcated model. The effect of friction coefficient,bond strength and porosity on the microscopic mechanical characteristics was investigated through further analysis of microscopic parameters,which reveals the mutual-relationship between the two. In addition,the research results show that the response of microscopic mechanical characteristics can be adjusted by controlling the value of meso-structure parameters,and therefore certain suggestions were made on the selection of microscopic parameters,which would provide reference for the PFC test in future.