不排水条件下土石混合料双轴压缩离散元模拟  

Discrete element simulation of soil-rock mixture under biaxial compression under undrained condition

作　　者：胡军霞 马一跃 张仕贤 董辉[3] 余巍 HU Jun-xia;MA Yi-yue;ZHANG Shi-xian;DONG Hui;YU Wei(Ship and Construction Engineering Branch,Jiaxing Nanyang Polytechnic Institute,Jiaxing 314001,China;Zhejiang Communications Construction Group Co.,Ltd.,Hangzhou 310000,China;College of Civil Engineering and Mechanics,Xiangtan University,Xiangtan 411100,China)

机构地区：[1]嘉兴南洋职业技术学院船舶与建筑分院,嘉兴314001 [2]浙江交工集团股份有限公司,杭州310000 [3]湘潭大学土木工程与力学学院,湘潭411100

出　　处：《计算力学学报》2022年第5期661-669,共9页Chinese Journal of Computational Mechanics

基　　金：浙江省教育厅一般科研项目(Y201942772);湖南创新型省份建设专项经费(2019RS1059);湖南省教育厅重点项目(19A477)资助.

摘　　要：基于离散单元法构建了考虑碎石形状的柔性边界不排水双轴压缩模型,研究了11组不同含石量土石混合料在不排水条件下的宏细观力学特性。研究发现,(1)土石混合料强度随含石量增加先增后减,含石量超过约60%时形成碎石骨架,强度快速增长;含石量约80%时强度和内摩擦角最大;含石量增加,混合料黏聚力逐渐减小。(2)不排水受载下,土石混合料孔隙水压力先正后负、先增后减。含石量较小时,含石量增加,混合料孔隙水压力变化较小,混合料在碎石骨架形成初期孔隙水压力增加;碎石骨架完全形成后最大孔隙水压力减小。(3)含石量小于约30%时,混合料应变局部化呈规则剪切带,随后含石量增加破坏规则剪切带,当含石量约为80%时,混合料再次形成规则剪切带。含石量增加,配位数逐渐减小,颗粒间接触力在含石量小于60%时随含石量增加缓慢增长,超过70%时则快速增长。An undrained biaxial compression model with a flexible boundary considering the shape of macadam is constructed by the discrete element method.The macro-meso mechanical properties of 11 groups of soil-rock mixtures with different stone contents under undrained conditions were studied.It is found that:(1)The strength of the soil-rock mixture increases at first and then decreases with the increase of stone contents.The strength of the crushed stone skeleton formed by the mixture containing more than 60%stone increases rapidly.The maximum strength and internal friction angle are obtained when the stone content is about 80%.The cohesion of the mixture decreases with the increase of stone contents.(2)Under undrained loading,the pore water pressure of the soil-rock mixture is first positive and then negative first increases and then decreases.When the stone contents are small,the change of pore water pressure of macadam mixture is small.The pore water pressure of the mixture increases at the initial stage of the formation of the crushed stone skeleton,and the maximum pore water pressure of the macadam skeleton decreases.(3)The strain localization of soil-rock mixture with stone contents less than 30%is a regular shear zone.The stone contents increases to destroy regular shear,and when the stone contents are about 80%,the mixture forms a regular shear zone.With the increase of stone contents,the coordination number decreases gradually,and the indirect contact force of particles increases slowly with the increase of stone contents when the stone contents are less than 60%,and increases rapidly when it exceeds 70%.

关 键 词：土石混合料 离散元 不排水 含石量 宏细观特性 

分 类 号：TU452[建筑科学—岩土工程]