双轴压缩条件下碎石集料静力剪切特性研究  

Static Shear Behavior of Crushed Rock Aggregate Subjected to Biaxial Compression

作　　者：王鹏程[1] 刘建坤[1] 李旭[1,2] 房建宏 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]多年冻土区公路建设与养护技术交通行业重点实验室青海研究观测基地,青海西宁810001

出　　处：《铁道学报》2014年第6期87-92,共6页Journal of the China Railway Society

基　　金：国家自然科学基金(41371081;51378057);国家基础研究计划(2012CB026104);北京交通大学博士生创新基金(KCTB12023536)

摘　　要：基于离散单元法,利用PFC2D内置Fish语言编制碎石集料双轴实验条件,结合计算机语言与PFC2D中Clump命令编制将球形单元转化为随机多边形块体单元的程序。通过对比室内大型三轴试验对数值模型进行参数标定与验证,在此基础上分析3种典型粒径碎石集料的应力-应变特性以及抗剪强度特性。结果表明,围压对集料的应力-应变特性影响明显。对于不同粒径的碎石集料而言,随着围压的增加,偏应力峰值增加而应力比减小;在本文选定的围压范围内碎石集料均呈现出先压缩最终剪胀的特性,围压越大,压缩量大,最终的剪胀越不明显;碎石集料的强度包络线为非线性,相同围压条件下的抗剪强度随着粒径的增大而增加;表征摩擦角随围压的增加而减小,相同围压下,粒径越大,表征摩擦角也越大。With the discrete element method（DEM ） ,biaxial compressions test conditions for crushed rock aggre-gate were established in the Fish language and the Clump logic commands in PFC 2D were incorporated into the computer language to simulate the crushed rock aggregate of irregular shapes .Compared with large-scale labo-ratory triaxial tests ,the parameters of the numerical model were calibrated and validated .The stress-deforma-tion and shearing strength of the crushed stone aggregate of three typical particle sizes were analyzed .The re-search results demonstrate as follws ：The confining pressure influences the stress-strain characteristics of aggre-gate significantly ;for aggregate of different particle sizes ,along with adding of the confining pressure ,the peak deviatoric stress increases while the stress ratio decreases ;within the specified range of confining pressure initial compression and subsequent dilation are observed with the aggregate ,the higher the confining pressure ,the lar-ger the compression and the smaller the dilation ;the shear strength envelope of the aggregate is nonlinear ,under the same confining pressure ,the shear strength increases with increasing of particle sizes ;the apparent friction angle decreases with adding of the confining pressure ,under the same confining pressure ,the larger the particle size of the aggregate ,the larger the apparent friction angle .

关 键 词：碎石路基 离散元 静力剪切特性 双轴压缩 

分 类 号：TU45[建筑科学—岩土工程]