湖南宁乡王家湾滑坡特征与变形机制分析

CHARACTERISTICS AND DEFORMATION MECHANISM OF WANGJIAWAN LANDSLIDE IN NINGXIANG,HUNAN

2017年7月1日,湖南省宁乡市沩山乡祖塔村王家湾组后山发生滑坡,造成9人死亡。滑坡后缘高程400m,前缘高程310m,滑源区斜长180m,最大宽130m,体积约8.04×10~4 m^3,水平滑移距离达300m。滑坡区地处湘中侵蚀剥蚀低山地貌,地形坡度30°～40°,出露地层岩性为震旦系下统金家洞组板状页岩,表层为第四系残坡积碎石土,为一浅层土质顺层滑坡,在降雨和人类活动的共同作用下诱发滑动。研究表明,王家湾滑坡属于牵引式滑坡,具有多级变形破坏特征,经历了临空面形成、第一级变形破坏、第二级变形破坏、第三级变形(潜在破坏)等变形过程。

On July 1,2017,the Wangjiawan landslide occurred in Zuta Village,Weishan Township,Ningxiang City,Hunan Province,killed 9 people.The elevation of the landslide trailing edge was 400 meters and the elevation of the leading edge was 310 meters.The sloping area of the sliding source area is 180 meters long and the maximum width is 130 meters.Its volume was about 80,400 square meters and the horizontal slip distance was 300 meters.The landslide area was located in the middle part of Hunan Province where the eroded and degraded low mountain topography is located.The terrain slope is 30-40 degree.The exposed lithology was plate-shaped shale in the Lower Sinian to the Jijialin Formation and Quaternary sedimentary debris in the surface,A hallow layer of soil along the landslide,induced by the joint action of rainfall and human activities slip.The research shows that the Wangjiawan landslide belongs to the traction type landslide and has the characteristics of multi-stage deformation and failure,experienced the deformation process of the formation of the first plane,the first stage of deformation and failure,the second stage of deformation and failure,the third stage of deformation（potential damage）.