加载速率和摩擦系数对颗粒材料系统剪切强度的影响研究  

Influence of Loading Rate and Friction Coefficient on the Shear Strength of Granular Material System

作　　者：黄志刚 王轩 傅力 童立红 HUANG Zhigang;WANG Xuan;FU Li;TONG Lihong(Jiangxi Transportation Engineering Group Co.,Ltd.,Nanchang 330000,Jiangxi,China;Jiangxi Intelligent Maintenance Engineering Technology Research Center of Bridge,Nanchang 330000,Jiangxi,China;Jiangxi Hengtong Traffic Engineering Inspection Co.,Ltd.,Nanchang 330000,Jiangxi,China;Institute of Geotechnical Engineering,School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang,330013,Jiangxi,China)

机构地区：[1]江西省交通工程集团有限公司,江西南昌330000 [2]江西省桥梁智能养护工程技术研究中心,江西南昌330000 [3]江西省恒通交通工程检测有限公司,江西南昌330000 [4]华东交通大学土木建筑学院岩土工程研究所,江西南昌330013

出　　处：《力学季刊》2024年第4期1032-1042,共11页Chinese Quarterly of Mechanics

基　　金：江西省交通运输厅科技项目(2021H0004)。

摘　　要：颗粒材料的接触摩擦系数与加载速率效应对颗粒材料系统的抗剪强度有重大影响.为此,采用离散单元法模拟了颗粒材料在柔性边界条件下的双轴压缩试验,分析了不同加载速率和摩擦系数组合下的颗粒材料宏观力学特性.并基于颗粒材料的“率态剪切强度理论”模型,进一步研究了加载速率与摩擦系数对颗粒材料系统“旋转滑移比例”和剪切强度的影响规律.结果表明,率态剪切强度理论模型从本质上揭示了颗粒材料体系的宏-细观之间的联系,可以较好地描述颗粒材料系统宏观剪切强度;颗粒材料系统的剪切强度随加载速率增大而提高,但存在临界值,当加载速率低于该临界值时,加载速率效应可以忽略;试样的剪胀性与滑动摩擦系数密切相关,颗粒形状的不规则性可以在保持试样剪胀性一致的同时,显著提升抗剪强度;剪切带内的颗粒旋转滑移比例同时受到加载速率与摩擦系数的影响,且对滑动摩擦系数变化的敏感性较高;“参考速度”与旋转滑移比例变化趋势相反,随加载速率增大、摩擦系数减小而显著增大.通过建立颗粒旋转滑移比例、加载速率与广义摩擦系数的定量关系,可为进一步研究颗粒材料率效应强度提供理论指导.Particle contact friction coefficient and loading rate effects have significant influences on the shear strength of granular material system.For this purpose,the flexible biaxial compression tests are simulated by the discrete element method to investigate the macroscopic mechanical properties under different combinations of loading rates and friction coefficients.Based on the“rate-state shear strength theory”,the influences of loading rates and friction coefficients on the“rotation-slip ratio”and shear strength of granular material system are further investigated.The results indicate that the rate-state shear strength theory can essentially reveal the macro micro relationship of particle material systems,and the macroscopic shear strength of granular material specimens can also be accurately described.The shear strength of granular material system increases with the increase of loading rate.However,there exists a critical loading rate below which the loading rate effect is negligible.The shear expansion of specimen is closely related to the sliding friction coefficient,and the irregularity of particle shape can significantly enhance the shear strength while maintaining a consistent shear expansion.The evolution of rotation-slip ratio in the shear band is affected by both the loading rates and the friction coefficients,with higher sensitivity to the sliding friction coefficient.Compared with the rotation-slip ratio,the“reference velocity”has an opposite trend,which increases significantly with the increase of loading rate and the decrease of friction coefficient.By establishing a quantitative relationship between the particle rotation slip ratio,the loading rate,and the generalized friction coefficient,theoretical guidance can be provided for further researches on the rate sensitive strength of granular materials.

关 键 词：颗粒材料 加载率效应 离散单元法 摩擦系数 颗粒旋转 

分 类 号：TU43[建筑科学—岩土工程]