砂砾石土渗透变形特性的应力状态相关性试验研究  

Experimental of study on the relevance between stress state and seepage failure of sandy-gravel soil

作　　者：蒋中明[1] 王为[1] 冯树荣[2,3] 钟辉亚[2,3] 

机构地区：[1]长沙理工大学水利工程学院,湖南长沙410114 [2]中国水电顾问集团中南勘测设计研究院,湖南长沙410014 [3]水能资源利用关键技术湖南省重点实验室,湖南长沙410014

出　　处：《水利学报》2013年第12期1498-1505,共8页Journal of Hydraulic Engineering

基　　金：'十二五'科技支撑计划课题(2012BAK03804);中国水电工程顾问集团科技计划项目(CHC-KJ-2008-08-02)

摘　　要：渗透变形是砂砾石土地基及堤防结构破坏的常见形式之一。影响砂砾石土渗透变形的因素很多,其中颗粒级配及应力状态是最重要的两个因素。为研究土体应力状态大小对砂砾石土渗透变形临界水力梯度的影响,通过研制大直径渗透变形仪加载系统,完成了侧限条件下砂砾石土在0.1、0.3、0.6、0.9MPa铅直应力作用下的渗透变形试验。试验成果及理论研究都表明砂砾石土渗透变形临界水力梯度随着应力状态的提高而加大,两者之间近似呈线性增加关系。渗透变形过程中,砂砾石土产生的渗透挤密和潜蚀现象是引起渗透系数演化的内在原因;基于渗透系数先减小再增大的变化规律,提出了应用渗透系数变化过程线确定渗透变形临界水力梯度的新途径。Seepage failure is one of the destructive types of levee structure and foundation in sandy-gravel soil stratum. Seepage failure of sandy-gravel soil is influenced by many factors. Especially, the grain compo- sition and the stress state are the most important factors. To explore the influence of stress state in the soil mass on the critical hydraulic gradient of seepage failure, a loading system for seepage failure experiment has been developed. The seepage failure experiments of sandy-gravel soil samples, which are under lateral confining condition, are accomplished by exerting 0.1, 0.3, 0.6 and 0.9MPa vertical stress on the top of the sample. Both the experimental and theoretical research results indicate that the critical hydraulic gradi- ent of sandy-gravel soil increases with the increment Of stress. There exists a linear relationship between the critical hydraulic gradient and stress. During the whole seepage failure process, the seepage clogging and suffusion are the intrinsic reasons to cause the evolution of coefficient of permeability. Based on the variation law of coefficient of permeability, a new approach to determine the critical hydraulic gradient is proposed through the variation process lines obtained from seepage failure experiment.

关 键 词：渗透变形 应力状态 临界水力坡降 渗透性演化规律 室内试验 

分 类 号：TV223.4[水利工程—水工结构工程]