基于离散元法的边坡填土剪切性能分析  

Analysis of shear performance of slope fill based on discrete element method

作　　者：匡俊[1,2] 陈芋如 朱仁民 曹建林 周俊 唐强[3] 孙俊芳 KUANG Jun;CHEN Yu-ru;ZHU Ren-min;CAO Jian-lin;ZHOU Jun;TANG Qiang;SUN Jun-fang(Jiangsu Suzhou Geological Engineering Survey Institute,Suzhou 215011,Jiangsu,China;The Fourth Geological Brigade of Jiangsu Geological and Mineral Bureau,Suzhou 215004,Jiangsu,China;Soochow University,Suzhou 215131,Jiangsu,China)

机构地区：[1]江苏苏州地质工程勘察院,江苏苏州215011 [2]江苏地质矿产局第四地质大队,江苏苏州215004 [3]苏州大学,江苏苏州215131

出　　处：《地基处理》2022年第5期380-386,共7页Journal of Ground Improvement

基　　金：国家自然科学基金项目(52078317);江苏省自然科学基金(优秀青年基金项目)(BK20211597);苏州市建设系统科研项目(2021-25,2021ZD02,2021ZD30);江苏省地质矿产勘查局科技项目(2021KY06)。

摘　　要：为了从微观角度分析边坡填土剪切性能的影响规律,以苏州市科技城凤凰山弃土场为研究对象,从现场取得的样品中将试样大体分为4种级配,利用颗粒流离散元软件构建直剪试验模型,研究关于剪切位移、剪切带以及接触网络的微观特征演化规律。研究结果表明,试样在剪切过程中表现出应变软化和屈服的特点。当试样进入剪切后期,剪应力达到峰值,其中中值粒径最大的杂填土试样的抗剪强度最高,峰值剪切应力达到327.74 kPa;颗粒位移呈水平带状分布,形成剪切带,宽度为1.52 cm左右;同时,力链网络中强力链显著聚集,与水平方向大约呈60°夹角,最大接触力达到1578.5 kN;随着中值半径的减小,剪切带的宽度以及最大接触力不断减小。在级配不良的样品内部,颗粒之间的嵌挤作用较弱,使得颗粒之间容易形成相对剧烈的相互错动。因此,黏性土中值粒径最小,剪切带宽度最小,最大的接触力最小,最容易发生剪切破坏。In order to analyze the influence of the shear behavior of the slope fill from micro-level,this paper takes Fenghuangshan abandoned soil site in Suzhou Science and Technology City as the research object.The samples obtained from the field were roughly divided into four gradations.The direct shear test model was constructed by using particle flow discrete element software to study the evolution of the microscopic characteristics of shear displacement,shear band and contact network.The results show that the specimens exhibit strain softening and yield characteristics during shearing.When the samples entered the later stage of shearing,the shear stress reached the peak value.Among them,the hybrid fill sample with the largest median particle size has the highest shear strength,and the peak shear stress reached 327.74 kPa.The particle displacement is distributed in a horizontal band,forming a shear band with a width of about 1.52 cm.At the same time,the strong chain in the force chain network is significantly gathered,forming an angle of about 60°with the horizontal direction,and the maximum contact force reached 1578.5 kN.The width of the shear band and the maximum contact force decrease with the decrease of the median radius.In the sample with poor gradation,the entrapment effect between particles is weak,which makes it easy to form relatively violent mutual dislocation between particles.Therefore,the cohesive soil has the smallest median particle size,the smallest shear band width,the smallest maximum contact force,and the most prone to shear failure.

关 键 词：边坡 直剪试验 离散元方法 级配 中值粒径 剪切带 力链网络 最大接触力 

分 类 号：TU413[建筑科学—岩土工程]