不连续级配无黏性土渗蚀演变特征研究  

Experimental investigation on evolution process of suffusion in gap-graded cohesionless soil

作　　者：张亮亮 邓刚 陈锐[1,2] 张茵琪 罗之源[1,2] ZHANG Liangliang;DENG Gang;CHEN Rui;ZHANG Yinqi;LUO Zhiyuan(School of Civil and Environmental Engineering,Harbin Institute of Technology,Shenzhen 518055,China;Guangdong Provincial Key Laboratory of Intelligent and Resilient Structures for Civil Engineering,Shenzhen 518055,China;State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing 100038,China)

机构地区：[1]哈尔滨工业大学(深圳)土木与环境工程学院,广东深圳518055 [2]广东省土木工程智能韧性结构重点实验室,广东深圳518055 [3]中国水利水电科学研究院流域水循环模拟与调控国家重点实验室,北京100038

出　　处：《岩土工程学报》2023年第7期1412-1420,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52278339);深圳市科技计划项目(KQTD20210811090112003);深圳市自然科学基金基础研究面上项目(JCYJ20190806144603586);中国水利水电科学研究院基本科研业务费项目(GE0145B032021)。

摘　　要：渗蚀是指土体内部细颗粒在渗流作用下克服粒间作用力逐步脱离,在粗颗粒骨架孔隙中发生迁移,并可能引起土骨架应力重分布和变形的侵蚀过程。利用自制局部孔压可测的三轴渗蚀装置,研究了细颗粒含量和相对密度对不连续级配无黏性土渗蚀行为的影响,并根据渗流沿程局部水力梯度的时空演变揭示了土体渗蚀发展的演变特征。结果表明:不连续级配无黏性土启动和破坏水力梯度随细颗粒含量/相对密度的增大而增大;相对密度越大侵蚀程度越小,且等向应力下相对密度增大到一定值后,土体会由渗流不稳定状态转变为稳定状态;土体渗蚀启动的内部表现是局部水力梯度的突变及渗流沿程上的不均匀分布。土体渗蚀导致细颗粒流失,土体孔隙比增大,在等向应力条件下,会引发体积收缩现象。The suffusion involves selective erosion and gradual migration of fine particles through the voids of soil skeleton formed by coarse particles under seepage flow.As a result,redistribution of soil skeleton stress and deformation of soil may be induced.In this study,a series of suffusion tests are carried out using the triaxial erosion apparatus with measurable local pore pressure.The effects of the initial fine particle content and initial relative density on the suffusion of a gap-graded cohesionless soil are investigated.According to the spatial-temporal evolution of local hydraulic gradients along seepage path,the evolution process of the suffusion is revealed.Test results show that both the initiation and the failure hydraulic gradients of the gap-graded cohesionless soil increase with the increase of the fine particle content and relative density.The cumulative loss of fine particles decreases significantly with the increase of the relative density.When the relative density increases to a certain value under isotropic stress condition,the gap-graded cohesionless soil will change from an unstable state of seepage to a stable one.Additionally,the internal manifestation of suffusion initiation of soil is the mutation and uneven distribution of local hydraulic gradient along seepage path.The suffusion will cause the loss of fine particles,as well as the increase of the void ratio.Under the isotropic stress condition,the volume shrinkage is induced.

关 键 词：不连续级配无黏性土 细颗粒含量 相对密度 渗蚀 局部演变特征 

分 类 号：TU43[建筑科学—岩土工程]