三轴试样高径比对试验影响的颗粒流数值模拟  

Numerical simulations of mechanical characteristics of coarse grained soil with different aspect ratios of tri-axial test

作　　者：陈锣芬[1,2] 朱俊高[1,2] 殷建华[3] 

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [2]河海大学岩土工程科学研究所,江苏南京210098 [3]香港理工大学土木工程系,中国香港

出　　处：《中南大学学报（自然科学版）》2015年第7期2643-2649,共7页Journal of Central South University:Science and Technology

基　　金：国家重点基础研究发展规划(973计划)项目(2013CB036404);高等学校博士学科点专项科研基金资助项目(20110094110002);高等学校学科创新引智计划项目(B13024)~~

摘　　要：基于离散元软件PFC3D,通过编制可破碎的颗粒簇单元,模拟三轴试验中不同高径比试样应力应变特性的差异,通过比较强度和变形参数差异探讨适合粗粒土的高径比。研究结果表明:高径比越小,试验得到的内摩擦角越大,围压越大,由于颗粒破碎导致的内摩擦角越小;满足莫尔-库仑准则破坏面的最小高径比随着围压的增加而减小,但都大于现在室内试验常用的高径比;峰值强度随着高径比的增加而减小,随着围压的增大,不同高径比之间峰值强度相对误差减小;割线模量与高径比呈折线形关系;不同高径比之间割线模量的差异随高径比范围的不同而不同,且最小高径比的割线模量与现在室内试验常用高径比的割线模量在低围压下差异较大。依据模拟结果,认为粗粒土的三轴试样高径比应大于2.5。The influences of mechanical characteristics and particle breakage with different aspect ratios were analysed based on DEM software PFC3D, and cluster element considering of particle breakage was developed. Meanwhile, the aspect ratio suitables to coarse grained soil was discussed by means of strength and deformation parameter. The results show that the smaller the aspect ratio, the bigger the friction angle, and that the bigger the pressure, the smaller the friction angle as a result of particle breakage. The minimum aspect ratio that satisfies Mohr-Coulomb criterion decreases with the increase of pressure, but each of them is larger than existing laboratory test aspect ratio. The peak strength decreases with the increase of aspect ratio, and so does relative error of the peak strength. The relationship between secant modulus and aspect ratio shows that the differences of secant modulus vary from aspect ratio to aspect ratio, and that there exists significant difference between the minimum aspect ratio and existing one. So, for the coarse grained soil, the aspect ratio should be larger than 2.5.

关 键 词：粗粒土 高径比 PFC3D软件 峰值强度 割线模量 

分 类 号：TU411[建筑科学—岩土工程]