土石混合料剪切特性影响因素的离散元数值研究  

PARTICLE DISCRETE ELEMENT NUMERICAL STUDY ON FACTORS OF SHEAR STRENGTH CHARACTERISTICS FOR SOIL-ROCK MIXTURE

作　　者：杨忠平[1,2,3] 田鑫 雷晓丹[1,4] 蒋源文 刘新荣 胡元鑫[5] YANG Zhongping;TIAN Xin;LEI Xiaodan;JIANG Yuanwen;LIU Xinrong;HU Yuanxin(Key Laboratory of New Technology for Construction of Cities in Mountain Area,Ministry of Education,Chongqing University,Chongqing 400045,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China;National Joint Engineering Research Center for Prevention and Control of Environmental Geological Hazards in the TGR Area,Chongqing University,Chongqing 400045,China;Taiyuan University,Department of Architectural Engineering,Taiyuan 030032,China;Headquarters of Chongqing Yuwu Airport,Chongqing 401120,China)

机构地区：[1]重庆大学山地城镇建设与新技术教育部重点实验室,重庆400045 [2]重庆大学土木工程学院,重庆400045 [3]重庆大学库区环境地质灾害防治国家地方联合工程研究中心,重庆400045 [4]太原学院建筑工程系,太原030032 [5]渝武机场建设指挥部,重庆401120

出　　处：《工程地质学报》2020年第1期39-50,共12页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:41772306);国家重点研发计划项目(资助号:2018YFC1504802);中央高校基本科研业务费资金(资助号:2019CDXYTM0032)~~

摘　　要：土石混合料剪切特性控制着高填方边坡的稳定性。土石混合料特殊的结构、物质及粒径组成等极其复杂,为探究土石混合料剪切特性影响因素及其规律,在室内试验基础上,基于PFC2D构建了颗粒离散元数值模型,分析了颗粒级配、初始孔隙率、块石尺寸及块石形状等因素对土石混合料剪切特性的影响。结果表明:土石混合料的剪应力-剪切位移曲线主要包括4个阶段:弹性变形、局部剪切、剪切破坏以及残余变形;块石形状、颗粒级配及初始孔隙率对土石混合料的破坏模式无明显影响,破坏模式均为应变软化型;当土石混合料的颗粒级配较差时,剪应力随剪切位移的增加出现较大波动,曲线出现明显"跳跃"现象;当含石量一定时,相同法向应力条件下,块石尺寸越大,土石混合料的抗剪强度越大,且随着法向应力的增大,不同块石尺寸的试验组之间抗剪强度差值也越大,块石尺寸对土石混合料抗剪强度的影响越明显。The shear characteristics of soil-rock mixture( S-RM) control the stability of the high fill slope. The special structure,material and particle size composition of soil-rock mixture are extremely complicated. This paper explores the influencing factors and laws of shear properties of soil-rock mixture on the basis of laboratory experiments. It constructs the particle discrete element numerical models with PFC2 Dto study the influence of particle gradation,initial porosity,rock size and rock shape on the shear characteristics of soil-rock mixture. The results shows that: the shear stress-shear displacement curves of soil-rock mixture can be divided into four phases including elastic,local shear,shear failure and residual deformation. The rock shape,particle gradation and initial porosity have no significant influence on the failure mode of soil-rock mixture,and the failure mode is strain softening. When the particle gradation of soil-rock mixture is poor,the shear stress fluctuates largely with the raising of shear displacement,and the curve shows obvious"jump"phenomenon. When the rock content is constant,under the same normal stress condition,the larger the stone size,the larger the shear strength of the S-RM. As the normal stress increases,the difference in shear strength between the test groups of different rock sizes increases,and the effect of rock size on the shear strength of soil-rock mixture is more obvious.

关 键 词：土石混合料 剪切特性 颗粒离散元 

分 类 号：TU443[建筑科学—岩土工程]