甘肃省庄浪县下寨村滑坡—堰塞湖链式灾害特征与滑坡稳定性分析

ANALYSIS OF LANDSLIDE-DAMMED LAKE CHAIN HAZARD AND LANDSLIDE STABILITY IN XIAZHAI VILLAGE,ZHUANGLANG COUNTY,GANSU PROVINCE

2020年汛期以来庄浪县降雨量超过历年平均值的11.5%,8月31日9时庄浪县郑河乡下寨村老滑坡整体复活滑动,滑坡长355.0 m,宽220.0 m,面积83668.0 m^(2),厚度12.0~20.0 m,体积约130.0×10^(4)m^(3),堆积体堵塞窑家河及支沟形成2处小型堰塞湖。本次调查运用工程地质调绘、无人机航测、工程地质勘查等技术手段进行了系统的分析,在获取了相关数据基础上,利用无人机航测高清影像比对和SlopeLE软件计算对滑坡稳定性进行了综合判定。通过2020年8月和2021年8月航测高清影像对比,滑坡前缘变形迹象极为明显,稳定性差。SlopeLE软件计算可知,滑坡自重工况下处于基本稳定状态,降雨工况处于欠稳定状态,地震工况处于不稳定状态。计算结果与航测比对数据基本吻合,在不利工况下极易发生滑动,存在再次堵塞河道形成堰塞湖的可能。

Since the flood season in 2020,the rainfall in Zhuanglang County has exceeded 11.5%of the average value over the years.At 9:00 on August 31,the old landslide in Xiazhai Village,Zhenghe Township,Zhuanglang County has been revived and slid.The landslide is 355.0 m long,220.0 m wide,83668.0 square meters in area,12.0~20.0 m thick,and about 1300000 cubic meters in volume.The accumulation blocks the Yaojia River and its tributaries to form two small barrier lakes.This survey has carried out systematic research by means of engineering geological mapping,unmanned aerial survey,engineering geological exploration and other technical means,and obtained relevant data.The landslide stability has been comprehensively judged by the use of unmanned aerial survey high-definition image comparison and SlopeLE software calculation.The results show that through the comparison of aerial survey high-definition images in August 2020 and August 2021,the landslide front edge has obvious signs of deformation and poor stability;SlopeLE software calculation shows that the landslide is basically stable under the dead weight condition,the rainfall condition is unstable,and the earthquake condition is unstable.It can be seen that the calculation results are basically consistent with the comparison data of aerial survey.It is very easy to slide under adverse conditions,and there is the possibility of blocking the river again to form a barrier lake.