基于抗转动线性接触模型的路基碎石集料双轴压缩试验离散元模拟  

Discrete Element Simulation of Biaxial Compression Test of Subgrade Crushed Stone Aggregate Based on Anti Rolling Resistance Linear Contact Model

作　　者：胡海波 HU Hai-bo(China Railway Shenyang Bureau Group Co.Lid.,Shenyang 1100,China)

机构地区：[1]中国铁路沈阳局集团有限公司,沈阳市110001

出　　处：《公路》2022年第8期50-55,共6页Highway

基　　金：辽宁省“兴辽英才计划”青年拔尖人才资助项目,项目编号XLYC2007146。

摘　　要：碎石集料作为一种常用于路基工程中的颗粒材料,颗粒形状对其力学性质有着重要的影响。对颗粒形状研究大多采用离散元软件(PFC)对其进行模拟。现有研究对颗粒形状的模拟方法大致分为以下两种:一是以多个圆形或球形单元黏接而成的颗粒簇来模拟颗粒的真实形状;二是采用抗滚动线性接触模型来模拟非圆形颗粒间的咬合嵌固现象。前者所需的圆形或球形单元较多,计算量较大;后者模型颗粒数量较少,相较于前者能提高运算能力。基于图像识别技术快速分析碎石集料形状指标扁平率e的分布特征,利用数值模拟堆积试验确定了抗转动线性接触模型对于不同扁平率颗粒模拟的滚阻系数的取值,建立双轴压缩数值模拟试验条件并与室内试验数据进行对比从而验证模型的正确性后,进行了符合群体形状分布特征的碎石集料双轴压缩数值模拟试验。试验结果表明:随着围压的增大,偏应力峰值在逐渐增大,峰值应变也逐渐增大;幂函数包络线能更好地对碎石集料的抗剪强度特征进行描述,其幂函数包络线表达式为τ=16.594σ^(0.494 6)。As a kind of granular material commonly used in subgrade engineering, gravel aggregate has significant influence on its mechanical properties. The research on particle shape mostly uses discrete element software(PFC) to carry out simulation. The existing research on particle shape simulation methods are roughly divided into the following two kinds: one is to simulate the real shape of particles by using particle clusters bonded by multiple circular or spherical units, and the other is to simulate the bite and embedding phenomenon between non-circular particles by using anti rolling linear contact model. The former requires more circular or spherical elements and requires more calculation, while the latter has less model particles, which can improve the calculation ability compared with the former. Based on the image recognition technology, in this paper the distribution characteristics of the shape index flattening rate e of crushed stone aggregate are quickly analyzed, the value of the roll resistance coefficient of the anti rotation linear contact model for the simulation of particles with different flattening rate are determined by using the numerical simulation stacking test, the test conditions of biaxial compression numerical simulation are established, and comparisons with the indoor test data are made to verify the correctness of the model. The numerical simulation test of biaxial compression of crushed stone aggregate in accordance with the characteristics of group shape distribution is carried out. The test results show that with the increase of confining pressure, the peak value of deviatoric stress and peak strain increase gradually, and the power function envelope can better describe the shear strength characteristics of gravel aggregate, and its power function envelope expression is.

关 键 词：岩土工程 碎石集料 离散元 抗滚动线性接触模型 扁平率 双轴压缩试验 

分 类 号：U416.1[交通运输工程—道路与铁道工程]