橡胶砂剪切特性的细观数值模拟  

Micro-mechanical simulation of shear properties of rubber-sand mixtures

作　　者：周恩全[1] 张蒋浩 陆建飞[1] ZHOU Enquan;ZHANG Jianghao;LU Jianfei(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang,Jiangsu 212013,China)

机构地区：[1]江苏大学土木工程与力学学院,江苏镇江212013

出　　处：《江苏大学学报（自然科学版）》2022年第3期351-358,共8页Journal of Jiangsu University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51508236);中国博士后基金资助项目(2015M580397);南京市交通运输科技项目(2022);江苏大学高级人才科研启动基金资助项目(15JDG172)。

摘　　要：为了研究橡胶砂剪切特性的细观机制,利用PFC3D离散元程序对橡胶砂的直剪试验进行数值模拟,分析了竖向正应力和橡胶掺量对橡胶砂剪切特性宏、细观力学行为的影响.结果表明,宏观层面上,区别于纯砂的应变软化特征,橡胶砂的应力与应变关系曲线表现出应变硬化特征,橡胶颗粒的加入显著改善了纯砂剪切强度特性,剪切强度随竖向正应力的增大而提高.细观层面上,橡胶颗粒的掺入提高了橡胶砂的配位数、强力链数和总力链数,形成了更加稳定的力链体系;竖向正应力为200 kPa时,相比于纯砂,掺入15%橡胶颗粒的橡胶砂配位数、强力链数和总力链数分别提高36.1%、25.3%和27.7%;相比纯砂,橡胶颗粒的掺入抑制了颗粒旋转,但对颗粒间法向接触力和切向接触力的分布和大小无显著影响.To investigate the micro-mechanical of shear properties of rubber-sand mixtures,the direct shear test of rubber-sand mixtures was numerically simulated by PFC3D discrete element program.The effects of vertical normal stress and rubber content on the macro and micro mechanical behaviors of rubber-sand mixtures were analyzed.The results show that the shear strength characteristics of pure sand are significantly improved by adding rubber particles.The shear stress-shear displacement curve of rubber-sand mixtures shows strain-hardening characteristic,and the shear strength is increased with the increasing of vertical normal stress.The addition of rubber particles leads to the increasing of coordination number,strong force chain number and total force chain number,which leads to the formation of more stable force chain system.When the vertical normal stress is 200 kPa,the coordination number,the strong force chain number and the total force chain number of rubber sand mixed with 15%rubber particles are respectively increased by 36.1%,25.3%and 27.7%compared with those of pure sand.Compared with pure sand,the addition of rubber particles inhibits particle rotation,while that has slight effect on the normal contact force and tangential contact force between particles.

关 键 词：橡胶砂 剪切特性 细观 力链 旋转 

分 类 号：TU411[建筑科学—岩土工程]