摘要
地震作用改变了碎石土斜坡岩土体的结构和物理力学性质,导致震后降雨诱发滑坡的数量和规模有明显的增大趋势。现有关于地震和降雨对碎石土斜坡稳定性影响的研究,多采用理论分析与数值分析的方法,缺乏验证手段。地震和降雨的耦合作用对滑坡的影响机理极其复杂,无法定量分析地震和降雨因子对坡体稳定性的影响。以汶川地震灾区震后降雨型碎石土斜坡为研究对象,通过开展一系列的振动台模型试验,并辅以人工降雨和坡顶加载手段,分析了震后降雨型碎石土斜坡的稳定性。试验结果表明:施加地震作用的斜坡表面及内部易形成裂缝,坡体结构上部振松、下部振密,导致坡体上部降雨入渗速度快,饱和区域扩大,岩土体强度下降,滑坡体增重,渗透力增大,坡体稳定性下降。地震与降雨共同作用时斜坡的稳定性要小于地震或降雨单独作用的稳定性。随着地震强度或降雨强度的增大,碎石土斜坡的稳定性呈下降趋势。当地震强度为0或0.1g时,降雨强度为100 mm/h较无降雨时,斜坡极限承载力下降的比例要远大于地震强度为0.2g或0.4g时。即当地震强度较小时,降雨对震后碎石土斜坡稳定性的影响要大于地震强度较大时。研究基于物理模型试验,定量分析了地震和降雨对碎石土斜坡稳定性的影响,可为震后降雨型碎石土滑坡的预测预警提供参考。
Earthquake changes the structure and physical-mechanical properties of the rock-soil mass in gravel soil slope,which increase the number and magnitude of rainfall landslides post earthquake.The existing researches on the effect of earthquake and rainfall on the gravel soil slope stability are mainly theoretical analysis and numerical analysis,but lack of validation.The coupling mechanism between earthquake and rainfall on landslide is extremely complex,therefore it is difficult to quantitatively analyze the effect of earthquake and rainfall on slope stability.Taking rainfall-induced gravel landslides post earthquake in Wenchuan earthquake stricken area as objects,a series of shaking table model tests,rainfall model tests and slope crest loading tests were carried out to analyze the stability of gravel landslide.The test results showed that the seismic loading induces fissures developing in slope crest and slope body,the upper slope becomes looser and the lower slope become more compressible.The rainfall seepage speed increase,the stability of rock-soil body decrease,the weight of landslide increase and the seepage force increase,thus the stability is obviously decreasing.The stability of rainfall-induced gravel landslide post earthquake is lower than rainfall or earthquake landslide.As the increasing of seismic intensity or rainfall intensity,the stability is obviously decreasing.As the seismic intensity is 0 or 0.1g and subsequent rainfall intensity is 100 mm/h,the drop rate of ultimate bearing capacity is relative large than the seismic intensity is 0.2g or 0.4g.It means that the effect of subsequent rainfall on slope stability post earthquake is more significant when the seismic intensity is relative low.Based on physical modelling experiments,the effect of earthquake and rainfall on slope stability was quantitatively analyzed,which can provide reference for the prediction and early warning of rainfall-induced gravel landslide post earthquake.
作者
苏立君
梁双庆
王洋
SU Lijun;LIANG Shuangqing;WANG Yang(Key Lab.of Mountain Hazards and Earth Surface Process,CAS,Chengdu 610041,China;Inst.of Mountain Hazards and Environment,CAS,Chengdu 610041,China;CAS Center for Excellence in Tibetan Plateau Earth Sci.,Beijing 100101,China;Univ.of Chinese Academy of Sci.,Beijing 100049,China;China–Pakistan Joint Research Center on Earth Science,Slamabad 44000,Pakistan)
出处
《工程科学与技术》
EI
CAS
CSCD
北大核心
2019年第4期12-20,共9页
Advanced Engineering Sciences
基金
国家自然科学基金国际(地区)合作与交流项目(41761144077)
中科院西部之光“一带一路”国际合作团队项目
关键词
地震
降雨
碎石土斜坡
坡顶加载
极限承载力
稳定性
earthquake
rainfall
gravel soil slope
slope crest loading
ultimate bearing capacity
stability
作者简介
苏立君(1976—),男,研究员,博士.研究方向:滑坡机理.E-mail:sulijun1976@163.com;通信联系人:梁双庆,E-mail:liangshuqngqing812@126.com.
