黏性土-结构接触面剪切变形时的渗透机理分析  

Analysis of seepage mechanism on clayey soil-structure interface under shear

作　　者：刘千惠 王翔南[1] 湛正刚 于玉贞[1] 吕禾[1] LIU Qianhui;WANG Xiangnan;ZHAN Zhenggang;YU Yuzhen;LÜHe(State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084;Power China Guiyang Engineering Co.Ltd.,Guiyang 550081)

机构地区：[1]清华大学,水沙科学与水利水电工程国家重点实验室,北京100084 [2]中国电建集团贵阳勘测设计研究院有限公司,贵阳550081

出　　处：《水力发电学报》2021年第9期113-121,共9页Journal of Hydroelectric Engineering

基　　金：国家重点研发计划(2017YFC0404803);黔科合平台人才([2018]5630);国家自然科学基金(U1965206)。

摘　　要：高心墙堆石坝在心墙和岸坡混凝土垫层间常设有一层接触黏土。这层接触黏土在缓解心墙与混凝土之间较大的不协调变形的同时还应具有较强的抗渗能力。接触面附近土体在高水头作用下产生大剪切变形,处于复杂的应力、变形和渗流状态。工程界普遍对此处是否更容易发生渗透破坏抱有疑问。接触面剪切-渗流试验的结果显示,在土体与结构之间发生较大剪切错动的情况下,渗透性呈现减小的趋势,但对其机理尚不清楚。本文在Biot固结理论的基础上,结合剪切渗透系数模型反映物理状态和变形对渗流场的影响,利用接触面单元反映试验中不同部件之间的接触关系,建立多体-多场耦合分析方法,对接触面剪切-渗流试验进行了数值模拟。通过分析计算结果,揭示了在接触面剪切-渗流的过程中,土体内部的应力-变形和孔隙比的演化过程以及渗透特性的内在机理。High earth-core rockfill dams are often designed with a contact layer inserted between the earth core and concrete cushion to reduce the otherwise too large deformation gradient at the interface while retaining strong impermeability.Large shear deformation induced by high water pressure puts this contact layer under a complex strain-stress and seepage state,and much attention is drawn to whether it is more susceptible to seepage damage.Previous experimental studies have shown its permeability is lowered under large shear displacement between the earth core and structure,but the mechanism is not clear yet.This study conducts multi-field simulations using a multi-body model to shed light on the mechanism of interface seepage.Based on Biot’s consolidation theory,we develop a mathematical model to simulate the seepage across the interface under large shear deformation,adopting joint elements to describe the contact relations between different layers at the interface.The simulation results reveal the evolution process of stress-strain and void ratio in the soil specimen as well as the seepage mechanism of the interface under shear.

关 键 词：接触黏土 土-结构接触面 渗流机理 高土石坝 

分 类 号：TV641.1[水利工程—水利水电工程]