贵州晴隆红寨大型古滑坡复活变形特征及成因分析

Reactivation characteristics and genesis analysis of the large ancient landslide in Hongzhai,Qinglong County,Guizhou Province

2020年9月17日,贵州省晴隆县鸡场镇红寨村发生滑坡灾害,导致134栋房屋严重损毁,127户569人紧急避险。通过调查发现,红寨滑坡是一处规模达6.25×106 m^(3)的深层大型滑坡,地表房屋及基础设施破坏严重,但整个滑坡运动距离极短。通过对地形地貌和岩土体结构及物质成分组成的分析、水系变动判断及钻孔揭露的多层滑面等综合分析认为,红寨滑坡是一处顺层的复活古滑坡。为分析研究该滑坡的变形特征和复活成因,采用无人机航测、工程地质调查、岩土体勘查、地球物理勘探等手段,获取了详细的灾害发育特征、影响因素及古滑坡的辨识特征等数据。分析结果表明:红寨滑坡可根据变形破坏特征及应力传递方向分为A、B、C、D 4个分区,其中B区又根据相对滑移量分为B1、B2亚区;滑坡的变形复活是在高陡的地形地貌、复杂的岩体结构、软弱的工程岩组和持续地表水入渗等共同作用下发生的;滑坡后缘圈椅状地形、滑体与周围岩土体的物质差异、断层切割前缘及水系堆积物的变迁等多方面特征验证了古滑坡的事实。

On September 17,2020,a landslide occurred in Hongzhai Village,Jichang Town,Qinglong County,Guizhou Province,resulting in serious damage to 134 houses and emergency evacuation of 569 people from 127 households.Investigation revealed that the Hongzhai landslide is a deep-seated large-scale landslide with a volume of approximately 6.25×106 m^(3).Although surface buildings and infrastructure were severely damaged,the overall movement distance of the landslide was extremely short.Through comprehensive analysis including terrain geomorphology,rock and soil structure and material composition analysis,assessment of hydrological changes,and disclosure of multiple slip surfaces through borehole drilling,it was concluded that the Hongzhai landslide is a resurrected ancient landslide along bedding planes.In order to analyze and study the deformation characteristics and resurrection causes of the landslide,methods including UAV aerial survey,engineering geological survey,rock and soil mass investigation,and geophysical exploration were employed to obtain detailed data on disaster development characteristics,influencing factors,and identification features of ancient landslides.The results show that the Hongzhai landslide can be divided into four zones(A,B,C,D)based on deformation and stress transfer direction,with zone B further divided into subzones B1 and B2 based on relative displacement.The deformation and resurrection of the landslide occurred under the joint effects of steep terrain,complex rock mass structures,weak engineering rock masses,and continuous surface infiltration.Various features such as the arm-chair shaped topography at the back edge of the landslide,material differences between the slide body and surrounding rock and soil masses,fault-cutting front edges,and changes in hydrological sedimentation verify the existence of the ancient landslide.