考虑场地效应的多点地震动作用下边坡永久位移分析  

Permanent displacement of slopes under multi-point earthquake ground motions considering site effects

作　　者：宋健[1,2] 潘驭航 陆朱汐 姬建 张飞[1,2] 高玉峰[1,2] SONG Jian;PAN Yuhang;LU Zhuxi;JI Jian;ZHANG Fei;GAO Yufeng(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210024,China;College of Civil and Transportation Engineering,Hohai University,Nanjing 210024,China)

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210024 [2]河海大学土木与交通学院,江苏南京210024

出　　处：《岩土工程学报》2025年第1期65-75,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52378335,52178325,U22A20594)。

摘　　要：地震动引起的边坡土层非线性动力响应可能导致坡体不同位置的地震动加速度时程不一致,从而对整个滑动体的极限平衡状态及之后的地震累积永久位移产生影响。为了研究场地效应对边坡地震永久位移的影响,基于极限平衡条分法,通过对不同土条赋予不同的水平和竖向地震动时程,推导出一种考虑场地效应的圆弧和任意形状滑面的多点地震作用下边坡永久位移分析方法。通过与有限差分软件FLAC的数值模拟结果进行对比,验证了该方法能够合理考虑地震动的场地效应。通过研究不同分布形式的多点地震动及竖向地震动对边坡永久位移的影响,结果表明:场地效应引起的水平地震动放大以及多点地震动不同分布模式会导致整个滑体平均地震惯性力作用位置发生改变,从而影响地震作用下滑动体沿滑面的永久变形量,竖向地震动对边坡地震位移影响较小。将方法应用于Lexington土石坝震后变形案例分析,计算得到的坝坡地震永久位移与实际震后观测值相吻合,证明了考虑场地效应的重要性及本文方法的合理性。The nonlinear dynamic response of slope soils caused by seismic motion may lead to inconsistent time histories of seismic acceleration at different positions of a slope.This will affect the limit equilibrium state and the cumulative seismic permanent displacement of the slope.In order to investigate the influences of site effects on the permanent displacement of slopes during earthquakes,a method for considering the multi-point earthquake ground motions is presented.The proposed method is derived based on the limit equilibrium slice method by considering different time histories of horizontal and vertical seismic motions for slices and can be used for circular and arbitrary-shaped slip surfaces.The method is capable to reasonably consider the site effects through a comparison with numerical results obtained by the FLAC.The effects of different distributions of multi-point ground motions and vertical ground motions on the permanent displacement of slopes are investigated.The results indicate that the amplification of horizontal ground motions and the different distributions of multi-point ground motions induced by the site effects have a significant impact on seismic slope displacement,while the influence of vertical ground motions are small.The method is then applied to a case study of post-earthquake deformation of the Lexington Dam.The calculated seismic permanent displacement agrees well with the observed post-earthquake values.This confirms the importance of considering the site effects and the rationality of the proposed method in this study.

关 键 词：地震边坡稳定性 场地效应 永久位移 极限平衡条分法 多点地震动 

分 类 号：TU435[建筑科学—岩土工程]