摘要
坝基作为水利水电工程重要基础设施的核心部分,其在地震作用下的动力响应和稳定性受到广泛关注。针对饱和砂土坝基的动力响应和液化规律,开展了两组超重力振动台试验,分析了饱和砂土地基在坝闸荷载作用下的地震响应规律。根据两组离心试验结果,地震作用下自由场地地基下层土体发生软化,上层土体发生液化喷砂,加速度放大系数和超静孔压比沿深度方向呈现先减小后增大的趋势;坝基在荷载边缘的土体中出现液化现象,加速度放大系数随深度逐渐减小而土体超静孔压比随深度逐渐增大。坝闸荷载能够增大坝基土体中的有效应力,减小超静孔压比。超静孔压消散后土体的密实度、刚度提高。最后,基于非线性有限元分析软件GEODYNA,对两组离心机试验进行了数值模拟,结果吻合较好。试验结果和数值模拟结果为饱和砂土坝基的设计与加固提供了依据。
As the core part of the important infrastructure of water conservancy and hydropower projects,the stability of dam foundation under earthquake is widely concerned.In order to solve the problem of the dynamic response and liquefaction law of saturated sand foundation under dam,two groups of centrifugal shaking table tests are carried out to analyze the influences of overlying loads on the seismic response of this foundation.The test results show that when there are no overlying loads on the foundation,the soil in the lower layer is softened during the vibration,while the soil in the upper layer is liquefied during the vibration,and the acceleration magnification factor of the foundation and the excess pore pressure ratio of the soil first decrease and then increase along the depth direction.When the foundation has overlying loads,liquefaction occurs in the soil at the edge of the overlying loads,and the acceleration magnification factor of the foundation increases gradually along the depth direction and the ratio of excess pore water pressure decreases gradually along the depth direction.The existence of overlying loads of dam can increase the effective stress of soil and reduce the excess pore pressure ratio.After the dissipation of excess pore pressure,the compactness and stiffness of soil is improved.Finally,based on the nonlinear finite element software GEODYNA,the numerical simulation of the two centrifuge tests is carried out,and the results are in good agreement.The results of the tests and the numerical simulation provide the basis for the design and reinforcement of the saturated sand dam foundation.
作者
杨凯文
李俊超
王锋
陈涛
汪玉冰
邹德高
刘京茂
YANG Kai-wen;LI Jun-chao;WANG Feng;CHEN Tao;WANG Yu-bing;ZOU De-gao;LIU Jing-mao(Center for Hypergravity Experimental and Interdisciplinary Research,Zhejiang University,Hangzhou 310058,China;MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering,Zhejiang University,Hangzhou 310058,China;Chengdu Survey,Design and Research Institute Co.,Ltd.of China Power Construction Group,Chengdu 610072,China;Sichuan Huaneng Luding Hydropower Co.,Ltd.,Chengdu 610041,China;School of Hydraulic Engineering,Dalian University of Technology,Dalian 116024,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2022年第4期778-786,F0003,F0002,共11页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金青年科学基金项目(51808490)。
关键词
坝基
液化
上覆荷载
地震响应
离心模拟
dam foundation
liquefaction
overlying load
seismic response
centrifuge modelling
