利用InSAR形变反演滑坡滑面运动特征——以汶川县布瓦村滑坡为例

INFERRING THE LANDSLIDE SLIDING SURFACE MOVEMENT CHARACTERISTICS BASED ON INSAR DEFORMATION-EXAMPLE OF THE BUWA VILLAGE LANDSLIDE IN WENCHUAN COUNTY

当前滑坡滑面运动特征获取多采用接触式手段,费时费力、成本高昂,且仅能获取稀疏点位滑面运动状态。因此,本文提出一种非接触式滑坡滑面运动特征获取方法,其基本思路是:基于位错理论建立滑坡表面形变与滑面运动间的关系模型,同时引入滑面运动平滑约束条件,最终以InSAR等技术获取的地表形变为约束,反演获得滑面运动特征。本文选择四川省汶川县布瓦村滑坡作为研究对象,以时序InSAR技术获取的滑坡坡面升降轨形变数据为约束,基于发展的理论方法反演获得布瓦村滑坡滑面几何与运动学参数,并结合野外勘查、Lidar观测以及模型残差较好地验证了反演结果的可靠性,其中反演升降轨模型残差仅3.1 mm·a^(-1)和3.4 mm·a^(-1)。反演结果显示,布瓦村滑坡滑面位于坡表以下平均~15.0 m深度处,滑面整体以沿坡向运动为主,最大运动量级达~80 mm·a^(-1),同时在坡体西侧中下部发现微量的垂直坡向运动。本文提出方法可方便、快速的获取空间连续的滑坡滑面运动特征,为滑坡灾害预警和失稳风险评估提供更为直接可靠的科学参考。

Currently,the contact method is mostly used to obtain the motion characteristics of the sliding surface of a landslide,which is time-consuming and costly.It can only provide information on the motion state of the sliding surface at sparse point positions.In this paper,a non-contact method is proposed to obtain the landslide sliding surface movement characteristics.The basic idea is to establish a relationship model between landslide surface deformations and sliding surface movement based on the dislocation theory.Simultaneously,a sliding surface movement smoothness constraint condition is introduced.Finally,the surface deformation obtained by InSAR and other technologies is used as constraints to estimate the motion characteristics of the sliding surface.The landslide in Buwa Village,Wenchuan County,Sichuan Province,is chosen as the research object in this paper.The geometric and kinematic parameters of the landslide slide surface of Buwa Village were obtained based on the developed theory and method,constrained by the observed surface deformation.The reliability of inversion results was verified through field surveys,Lidar observations,and model residuals.The residuals of the ascending and descending inversion model are only 3.1--mm-·-a^(-1)and 3.4--mm-·-a^(-1),respectively.The inversion results indicate that the sliding surface of the Buwa Village landslide is located at an average depth of~15.0--m below the slope surface.The sliding surface mainly moves along the slope,with a maximum movement of~80--mm-·-a^(-1).Additionally,vertical movement is observed in the middle and lower part of the west side of the slope.The method proposed in this paper enables the quick and easy acquisition of the spatial continuous motion characteristics of the landslide sliding surface.It provides a more direct and reliable scientific reference for landslide disaster warning and risk assessment.