渗流-流变耦合作用下深覆盖层面板堆石坝性态演化规律  

Seepage-creep Coupling Analysis of Concrete Face Rockfill Dam built on Alluvium Foundation

作　　者：温立峰[1] 李锋[2] 吴莉 WEN Lifeng;LI feng;WU Li(State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China,Xi'an University of Technology,Xi'an 710048,China;PowerChina Northwest Engineering Corporation Limited,Xi'an 710065,China)

机构地区：[1]西安理工大学省部共建西北旱区生态水利国家重点实验室,西安710048 [2]中国电建集团西北勘测设计研究院有限公司,西安710065

出　　处：《西北水电》2023年第5期7-14,共8页Northwest Hydropower

基　　金：国家自然科学基金(51909215).

摘　　要：修建在深厚覆盖层上的面板堆石坝地基和部分坝体处于饱和渗流状态,渗流和变形的耦合作用对坝基和坝体的变形具有一定的影响。通过采用Drucker-Prager塑性模型和时间硬化流变模型描述堆石料和覆盖层砂砾石材料的瞬时变形和流变变形,采用Signorini型变分不等式方法描述堆石料和覆盖层多孔介质材料的渗流过程,在此基础上基于动量守恒原理和Kozeny-Carman方程提出覆盖层上面板堆石坝渗流-流变耦合分析方法。基于渗流-流变耦合分析,研究了渗流-流变耦合作用下覆盖层面板堆石坝的力学特性,分析了渗流作用对面板堆石坝长期变形的影响规律,进而讨论了覆盖层上面板堆石坝的变形机制和演化过程。结果表明:覆盖层地基压缩变形使大坝最大变形位置向下移动至0.3倍坝高位置且面板承受较大的拉应力;大坝流变变形是面板堆石坝的重要变形来源,其引起的坝内沉降增量达27.3%,面板拉应力增量达5.1%;渗流效应对大坝流变变形具有一定的影响,但相对于流变效应引起的应力变形增量整体相对较小。The foundation and dam body below the seepage free surface are in the saturated seepage state for the concrete-face rockfill dam(CFRD)built on deep alluvium foundation.The seepage and stress coupling effect could influence the dam deformation behaviour.The Drucker-Prager plastic and time-hardening creep models are used to describe the instantaneous and creep deformations of rockfill and alluvium materials.The Signorini's type variational inequality method is adopted to describe the seepage process of the rockfill material and porous medium.On this basis,a seepage-rheology coupling analysis method for CFRD on deep alluvium foundation is proposed based on the principle of conservation of momentum and the Kozeny-Carman equation.Based on the seepage-rheology coupling analysis,the mechanical characteristics of CFRD on deep alluvium foundation under the coupling effect of seepage and rheology are studied,the influence of seepage on the long-term deformation of CFRD is analyzed,and then the deformation mechanism and evolution process of CFRD is discussed.The results show that the compressive deformation of the deep alluvium foundation moves the maximum deformation position of the dam downward to 0.3 times the dam height and the face plate bears large tensile stress;the rheological deformation of the dam is an important source of deformation of CFRD,which causes the settlement increment within the dam up to 27.3%,and the tensile stress increment of the concrete face reached 5.1%.The seepage effect has a certain influence on the rheological deformation of the dam,but the overall increment of stress deformation caused by the rheological effect is relatively small.

关 键 词：面板堆石坝 深覆盖层 渗流-流变耦合 变形规律 长期变形 

分 类 号：TV641.4[水利工程—水利水电工程] TU411[建筑科学—岩土工程]