考虑强度速率衰减效应的地震滑坡SPH-FEM模拟  

SPH-FEM simulation of landslide induced by earthquake considering velocity weakening effect of frictional strength

作　　者：魏星[1] 程世涛 谢相焱 陈睿[1] WEI Xing;CHENG Shitao;XIE Xiangyan;CHEN Rui(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Sichuan Vocational and Technical College of Communications,Chengdu 611130,China;Kunming Survey,Design and Research Institute Co.Ltd.of CREEC,Kunming 650200,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]四川交通职业技术学院,四川成都611130 [3]中铁二院昆明勘察设计研究院有限责任公司,云南昆明650200

出　　处：《岩土工程学报》2024年第8期1753-1761,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(41977235)。

摘　　要：基于SPH和FEM耦合的数值计算方法,引入滑动面摩擦强度的速率衰减模型,提出了一种能够模拟地震诱发滑坡破坏过程的数值模拟方法。基于所提数值方法模拟了唐家山地震滑坡,模拟结果与现场勘查结果及室内试验现象较为一致。基于模拟的滑动面上摩擦系数的演化过程,将唐家山滑坡的发生分为4个阶段:启动阶段、摩擦衰减阶段、低摩擦滑移阶段和逐步稳定阶段。模拟结果表明速度增加和摩擦强度衰减的相互促进,是触发滑体的高速运动的根本原因。提出采用滑体上作用的动摩擦力fd和动下滑力Td的比值R作为判别指标用于判断大型滑坡的启动,当首次出现R小于1时认为滑动面发生整体贯通并出现失稳启动。基于滑动面不同位置摩擦系数的演化,揭示了滑坡启动中滑动面摩擦强度衰减和滑动面的渐进贯通过程,解释了地震作用与滑动面摩擦参数速率衰减效应共同作用触发大型滑坡发生破坏的内在机理。Based on the SPH-FEM coupling method,a frictional velocity weakening model for sliding surface is introduced and a numerical simulation method which can simulate the whole failure process of the landslides triggered by earthquake is proposed.The Tangjiashan landslide is simulated by the proposed method,and the simulated results are consistent with the on-site investigations and the laboratory test results.Based on the calculated frictional strength on the sliding surface,the whole failure process of the Tangjiashan landslide is divided into four stages:the triggering stage,the frictional weakening stage,the low frictional stage and the gradually stabilizing stage.The simulated results indicate that the high-speed movement of the sliding body is triggered by the interaction of the increase of the velocity and the decrease of the frictional strength.The parameter R defined by the ratio of the dynamic frictional force fd to the dynamic sliding force Td is suggested to evaluate the failure of large landslides.When R less than 1 occurs for the first time,the stress on the sliding surface reaches the shear strength and slope failure occurs.Based on the evolution of friction coefficient at different positions of the sliding surface,the frictional weakening of the sliding surface and the gradual failure of the landslide are revealed.The large-scale landslide is supposed to be triggered by the joint effects of the earthquake and the frictional velocity weakening.

关 键 词：大型滑坡 滑动面 摩擦强度 速度衰减效应 SPH-FEM耦合方法 

分 类 号：TU435[建筑科学—岩土工程]