基于时序InSAR技术的响滩村滑坡形变特征分析

Deformation Monitoring and Analysis of the Landslide in Xiangtan Village Based on Time Series InSAR Technology

本文以四川省南充市仪陇县响滩村的山体滑坡为研究对象,采用前后2021年1月12日至2021年9月21日(共21景)Sentinel-1A的SAR影像数据,利用SBAS-InSAR技术获取了该滑坡年均形变速率和累积形变量等信息,根据获取的形变信息及光学影像特征对该区域滑坡范围进行了重新圈定,圈定了A、B、C三个次级滑坡区域,结合实地调查综合分析滑坡时空演变,3-4月份由于降雨冲刷,坡体开始缓慢形变,遇人为扰动后A区在6月中旬滑动,滑动后A区周界裂缝形成,一方面为B区的滑动创造了条件,随着时间的发展,降雨持续,最终带动B区在6月下旬-7月加速滑动,8月份降雨量陡然增加,A区、B区滑动加剧,拉裂了后缘坡面,并伴着局部坡面溜塌;C区较其他四个滑坡区活动性整体偏弱,根据时序曲线特征可知,C区形变时序与其他滑坡区没有明显的时间关系,因此推测C区为独立的滑动。结合降雨量数据可知,降雨对于响滩村滑坡活动有着直接而明显的影响,一般来说,降雨持续时间越长、强度越大,坡体出现形变加速的可能性越高。该研究结果表明时序InSAR技术对滑坡的早期识别预警、形变演化具有良好的监测效果,具有十分广阔的应用前景。

This article takes the landslide in Xiangtan Village,Yilong County,Nanchong City,Sichuan Province as the research object.Using Sentinel-1A SAR data from January 12,2021 to September 21,2021(a total of 21 scenes),SBAS-InSAR technology was used to obtain information on the average annual deformation rate and cumulative deformation variables of the landslide.Based on the obtained deformation information and optical image characteristics,the landslide range in the area was redefined,and three secondary landslide areas,A,B,and C,were delineated.Based on on-site investigation and comprehensive analysis of the spatiotemporal evolution of landslides,from March to April,due to rainfall erosion,the slope began to slowly deform.After encountering human disturbance,Zone A slid in mid June,and after sliding,cracks formed around Zone A's boundaries.On the one hand,this created conditions for Zone B's sliding.With the development of time,rainfall continued,ultimately driving Zone B to accelerate sliding in late June to July.In August,rainfall suddenly increased,and the sliding of Zone A and Zone B intensified,tearing the rear slope surface,And accompanied by local slope collapse;The overall activity of Zone C is relatively weak compared to the other four landslide areas.According to the characteristics of the time series curve,there is no obvious time relationship between the deformation time series of Zone C and the other landslide areas.Therefore,it is speculated that Zone C is an independent sliding zone.Based on rainfall data,it can be seen that rainfall has a direct and significant impact on the landslide activity in Xiangtan Village.Generally speaking,the longer the duration and intensity of rainfall,the higher the possibility of accelerated deformation of the slope.The research results indicate that time-series InSAR technology has a good monitoring effect on early identification,early warning,and deformation evolution of landslides,and has a very broad application prospect.