边坡主震响应方向性及余震效应的离心模型试验  

Centrifugal model tests on mainshock response directionality and aftershock effect of slopes

作　　者：李超[1,2] 管龙华 何健健 汪玉冰 LI Chao;GUAN Longhua;HE Jianjian;WANG Yubing(Center for Hypergravity Experiment and Interdisciplinary Research,Zhejiang University,Hangzhou 310058,China;MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学超重力研究中心,浙江杭州310058 [2]浙江大学软弱土与环境土工教育部重点实验室,浙江杭州310058

出　　处：《岩土工程学报》2023年第6期1285-1293,共9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)。

摘　　要：对含倾斜基岩面的砂土边坡开展50倍重力的离心模型振动台试验,探究主余震序列作用下边坡响应与变形的变化特征。首先通过响应的时程分析和谱分析讨论主震边坡加速度的放大效应,接着借助刚性楔形滑体模型解释主震响应方向性与放大系数的关系和截断效应产生的机理,最后通过累积变形探讨余震效应及其影响状况。研究表明,放大效应是一个与频率有关的量,随着高程的增加低频部分得到了不同程度的放大。而按照PGA定义的放大系数需要结合考虑边坡顺-逆坡向不同所导致的响应方向性问题,截断效应及其与响应方向性的关系则体现了边坡变形与响应的耦合作用。余震效应的分析指出某些部位因余震导致的总位移增量可以与主震引起的变形量相当,在工程设计中应当考虑余震的附加影响。A centrifugal model shaking table test with gravity of 50 times is carried out on a sandy slope containing an inclined bedrock interface to investigate the characteristics of changes in slope response and deformation under the action of the main shock-aftershock sequence.Firstly,the acceleration amplification effect of the mainshock is discussed through the time and spectral analysis,then the relationship between the mainshock response directionality and the amplification coefficient together with the mechanism of the truncation effect is explained using a model for rigid wedge-shaped sliding body.Finally,the aftershock effect and its influence are explored through the cumulative deformation.The results show that the amplification effect is frequency-dependent.The low-frequency part of the response is amplified to different degrees with the increase of elevation,while the amplification coefficient defined by PGA needs to be combined with the consideration of the response directionality due to the difference between downslope and upslope.The truncation effect and its relations with the response directionality reflect the coupling effect of deformation and response of the slope.The analysis of the aftershock effect points out that the total displacement increment of certain parts caused by aftershock can be comparable to that caused by the mainshock.This additional influence of aftershocks should be considered in engineering design.

关 键 词：主余震序列 离心模型试验 砂土边坡 放大效应 截断效应 

分 类 号：TU411[建筑科学—岩土工程]