初始静剪作用下含细粒砂土动力液化特性离散元分析  

Cyclic liquefaction behavior of silty sand considering initial static shear effect:a DEM investigation

作　　者：潘坤 李佩佩[1] 曹奕 吴祁新 杨仲轩[4] PAN Kun;LI Peipei;CAO Yi;WU Qixin;YANG Zhongxuan(College of Civil Engineering,Zhejiang University of Technology,Hangzhou 310014,China;Zhejiang Jiaogong Underground Engineering Co.,Ltd.,Hangzhou 310005,China;School of Civil Engineering,Wuhan University,Wuhan 430072,China;College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江工业大学土木工程学院,浙江杭州310014 [2]浙江交工地下工程有限公司,浙江杭州310005 [3]武汉大学土木建筑工程学院,湖北武汉430072 [4]浙江大学建筑工程学院,浙江杭州310058

出　　处：《岩土工程学报》2025年第2期417-427,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家重点研发计划项目(2023YFB2604200);国家自然科学基金项目(52178362,U2239251,52208336);浙江省建设厅项目(2022K073);浙江交工协同创新联合研究中心项目(ZDJG2021001)。

摘　　要：为研究含细粒砂土液化行为的微观机理,采用颗粒流程序PFC3D模拟了砂土在不排水循环荷载下液化特性,将含有少量细粒的砂土试样与净砂在相同初始状态参数下的循环响应进行了对比,研究了初始静剪和细粒含量对砂土动力液化特性的影响。模拟结果显示,不同静剪应力条件下,含细粒砂土呈现出两种典型的液化破坏模式:循环流动和残余变形累积。当试样表现为循环流动型响应时,配位数逐渐减小至4;而当土体破坏由残余变形累积导致时,配位数变化较小且组构模量始终大于0。相同初始状态和应力条件下,含细粒砂土在循环加载过程中的配位数变化量较净砂大,其抗液化能力也相应较大。此外,随着静剪应力增加,试样的配位数变化量逐渐增大,其抗液化动强度也随之增大。To gain more insights into the microscopic mechanism of the liquefaction behavior,the particle flow program PFC3D is used to simulate the liquefaction process of silty sands under undrained cyclic loading.The effects of the initial static shear stress and fines content on the cyclic liquefaction behavior of sand are investigated.The simulation responses of silty sand containing a small amount of fines are compared with those of clean sand under the same initial state parameters.The simulated results show that regardless of the fines content,different initial static shear stress conditions can result in two liquefaction failure patterns:cyclic mobility and residual deformation accumulation.Generally,the samples exhibit cyclic mobility accompanied by a decrease in the coordination number.The coordination number of samples under residual deformation accumulation changes slightly,while the fabric norm F is always greater than zero as the cyclic shearing proceeds.Under the identical initial state and stress conditions,the coordination number variation of fine-grained sand during cyclic loading is larger than that of clean sand,and its liquefaction resistance is also larger.Furthermore,a higher initial static shear level leads to a larger change in the coordination number and also an increase in the cyclic liquefaction resistance.

关 键 词：含细粒砂土 离散元模拟 初始静剪 细粒含量 循环液化 

分 类 号：TU411[建筑科学—岩土工程]