摘要
三峡库区新城区迁建多采用就地后靠方式,工程扰动叠加强降雨往往诱发滑坡失稳。基于重庆巫山江东小区金鸡岭滑坡,对其影响因素和成因机制进行探讨。工程扰动不仅是传统认为的后缘加载、前缘削脚作用,更重要的是坡体表层土方堆填阻断了滑坡体地表水泄流通道,使地表水向地下水转化。强降雨作用下滑坡体内地下水位明显升高,导致金鸡岭滑坡2018年8月1日前后发生较大变形。采取降水井抽排地下水等应急处置后,滑坡变形明显趋缓,可见工程扰动导致的地下水升高是该滑坡诱发的关键因素。数值模拟表明,工程扰动后稳定系数明显降低,对应堆填区渗流场变化明显,渗流加剧,孔隙水压力、水力梯度、总水头上升,结合达西定律与有效应力原理可知渗透力增加,抗剪强度削弱,诱发滑坡变形。
The resettlement of residents in the nearest possible areas is always applied in the Three Gorges Reservoir region,China.But engineering disturbances and heavy rainfall often induce the landslide instability.This paper discusses the impact factors and formation mechanism of the Jinjiling landslide in Jiangdong district,Wushan county,Chongqing,China.It shows that the cutting and filling of slopes lead to loading of the trailing edge and removal of material from the leading edge.More importantly,the filling of channels with surface soil blocks the surface water discharge channel along the landslide body,promoting the transformation of surface water into groundwater.Therefore the groundwater level in the Jinjiling landslide rose substantially under heavy rainfall,resulting in a large deformation on approximately August 1,2018.After emergency treatment,including groundwater pumping from the landslide body,the landslide deformation slowed considerably.It is analyzed that the groundwater rise caused by filling of the landslide body is the key factor of the landslide.The numerical simulation shows that the stability coefficient of the engineering decreases obviously after the disturbance of engineering,and the seepage field in the corresponding filling area changes obviously.The seepage is intensified,characterized as the increase in the pore water pressure,hydraulic gradient and total water head.Based on Darcy’s law and principle of effective stress,the increase of seepage force and decrease of shear strength induce landslide deformation.
作者
闫国强
殷跃平
黄波林
张枝华
代贞伟
YAN Guo-qiang;YIN Yue-ping;HUANG Bo-lin;ZHANG Zhi-hua;DAI Zhen-wei(Faculty of Engineering,China University of Geosciences,Wuhan,Hubei430074,China;China Institute of Geo-environment Monitoring,CGS,Beijing,100081,China;Hubei Key Laboratory of Disaster Prevention and Mitigation,China Three Gorges University,Yichang,Hubei443002,China;208Geological Team,Chongqing,400700,China;Wuhan Centre of China Geological Survey,Wuhan,Hubei430205,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2019年第A01期329-340,共12页
Rock and Soil Mechanics
基金
国家重点研发计划项目(No.2018YFC1504803)
三峡后续工作地质灾害防治项目(No.000121 2019C C60 001)&(ID:2018102849)
中国地质调查局项目(No.DD20190637)~~
关键词
三峡库区
边坡工程
金鸡岭滑坡
成因机制
数值模拟
Three Gorges Reservoir region
slope engineering
Jinjiling landslide
formation mechanism
numerical simulation