地震作用下分层土边坡多滑面变形破坏的数值模拟研究  

Numerical study of the deformation and failure of layered soil slopes with multiple sliding surfaces under earthquakes

作　　者：宋健[1,2] 陆朱汐 谢华威 吴凯莉 SONG Jian;LU Zhuxi;XIE Huawei;WU Kaili(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210000,Jiangsu,China;College of Civil Engineering and Transportation,Hohai University,Nanjing 210000,Jiangsu,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,江苏南京210000 [2]河海大学土木与交通学院,江苏南京210000

出　　处：《地震工程学报》2023年第2期296-305,共10页China Earthquake Engineering Journal

基　　金：国家自然科学基金面上项目(52178325)。

摘　　要：地震引起的滑坡对生命、环境和经济造成了巨大的威胁。目前,对于地震作用下边坡稳定性的研究主要集中在单一滑动面破坏模式,对于具有多个潜在滑动面边坡的地震稳定性研究比较欠缺。基于此,利用有限差分软件FLAC对不同边坡进行地震稳定性数值模拟,对比分析不同强度地震动作用下均质土体、分层土体和含软弱夹层土体边坡的滑动面演化过程和永久变形分布特征。结果表明:对于均质边坡,地震引起的滑动面为单一的整体滑动面,地震动强度的增加仅导致沿滑动面的永久变形量增大;对于非均质边坡,在地震作用下还可能形成通过土层交界面的局部滑动变形,且地震作用下最先形成和发生变形的滑动面与静力条件下得到的最小安全系数对应的最危险滑动面一致;同时,地震引起的边坡浅层和深层变形破坏存在复杂的相互影响,当局部浅层滑动先发生时,地震动的进一步增大很容易诱发更深层的坡体滑动,而当深层滑动先发生时,由于塑性变形影响地震惯性力向上部坡体的传播,浅层坡体的进一步滑动变形相对较难被触发。Landslides caused by earthquakes pose a great threat to life,the environment,and the economy.Present studies on slope stability under earthquakes mainly focus on the failure modes of single sliding surfaces,while studies on slope stability with multiple potential sliding surfaces are comparatively obscure.A numerical simulation is conducted on the seismic stability of different slopes by using the finite difference software FLAC.The evolution process of sliding surfaces and the distribution characteristics of permanent deformation of homogeneous soil slopes,layered soil slopes,and soil slopes with weak interlayers under different earthquake intensities are compared and analyzed.Results reveal that the sliding surface of homogeneous slopes caused by earthquakes exhibits a single sliding surface,and the increase in seismic intensity only leads to an increase in permanent deformation along the sliding surface.For heterogeneous slopes,seismic action may also trigger local sliding deformation at the soil interface,and the sliding surface initially formed under seismic action is consistent with the most dangerous sliding surface corresponding to the minimum safety factor obtained under static conditions.In addition,a complex interaction exists between the shallow and deep slope deformations and failures caused by earthquakes.If the shallow sliding occurs first,further increase in ground motion can easily induces deep slope sliding;if the deep sliding occurs first,then plastic deformation affects the propagation of seismic inertia force to the upper slope body;thus,the further sliding deformation of the shallow slope is relatively difficult to trigger.

关 键 词：地震边坡稳定性 数值模拟 滑动面 变形破坏 

分 类 号：TU43[建筑科学—岩土工程]