摘要
中国西南砂泥岩地层山区在强降雨条件下频发远程滑坡灾害,是防灾减灾领域亟待解决的关键问题。以2020年7月13日重庆武隆牛儿湾滑坡为例,通过无人机航飞、野外调查和地质条件分析等手段,运用PFC 3D模拟,对中国西南砂泥岩地层山区强降雨条件下流化滑坡远程运动成灾模式开展研究。研究结果显示:独特的地层结构(上部为第四系残坡积土,下部为砂泥岩)是导致滑坡顺层失稳,并远程流化运动的根本原因;强降雨条件是导致滑坡深层失稳、整体下滑,同时使表层残破积土层饱水流化远程运动的关键影响因素;顺层滑坡远程流化成灾模式主要表现出下层整体滑移、中层粗细颗粒混合和上层饱水流化的特征,流化过程可分为整体高位失稳—混合加速—运动流化堆积三个阶段。基于以上研究,认为砂泥岩地层山区的远程流化滑坡风险调查与预测过程应当充分基于滑体远程流化运动的成灾特点进行调查与评价,以此为防灾减灾提供定量化科学依据。
The frequent occurrence of remote landslide disasters under heavy rainfall in the mountainous area with sand-mudstone strata in southwest China is a critical issue to be solved in disaster prevention and mitigation.Taking the July 13,2020 Niuerwan landslide in Wulong,Chongqing as an example,technical means including UAV image,field investigation,geological condition analysis,and PFC 3D simulation were used to study the long-runout motion model of flowslide under heavy rainfall.The results show that the unique stratigraphic structure(Quaternary residual slope soil in the upper part and sand-mudstone in the lower part)is the root cause of the landslide instability and long-runout fluidization movement.Heavy rainfall is the key factor in causing the deep destabilization and overall decline of the landslide,and it also leads to the long-distance movement of the upper saturated residual soil.The long-runout fluidization disaster model of bedding landslide shows the characteristics of overall sliding of the lower layer,mixing of coarse and fine particles of the middle layer,and saturation fluidization in the upper layer.The longrunout fluidization process can be divided into three stages:the overall instability,the mixed acceleration,and the fluidization accumulation.Based on the above research,it is concluded that the investigation and prediction process of long-runout fluidization landslide in the mountainous area with sand-mudstone strata should be based on this particular disaster model to provide a quantitative scientific basis for disaster prevention and mitigation.
作者
吴伟乐
贺凯
高杨
李滨
刘朋飞
WU Weile;HE Kai;GAO Yang;LI Bin;LIU Pengfei(School of Geological Engineering and Geomatics,Chang’an University,Xi’an 710054,Shaanxi,China;Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;Key Laboratory of Active Tectonics and Geological Safety,Ministry of Natural Resources,Beijing 100081,China;Research Center of Neotectonism and Crustal Stability,China Geological Survey,Beijing 100081,China;Chongqing Institute of Geological Environment Monitoring,Chongqing 401122,China)
出处
《地质力学学报》
CSCD
北大核心
2022年第6期1115-1126,共12页
Journal of Geomechanics
基金
国家自然科学基金面上基金项目(42177172)
国家自然科学基金青年基金项目(41907257)。
关键词
牛儿湾滑坡
流态化
高位远程
顺层滑坡
Niuerwan landslide
fluidization
high-elevation and long-runout
bedding landslide
