基于InSAR的乌东德水电站库区边坡形变监测及分析

Monitoring and analysis of slope deformation in Wudongde Hydropower Station reservoirarea based on InSAR

水电站建成投产后,水库水位变化频繁,改变了库岸边坡原有的稳定性,易诱发边坡失稳破坏,从而对水电站的安全运行及周边居民区产生一定安全隐患。为了更好地掌握乌东德水电站蓄水过程中库区边坡的形变情况,通过SBAS-InSAR技术对该区域2020年5月至2022年8月间的升降轨哨兵数据进行解算,获取了研究区的地表形变特征;结合库水位变化情况、SAR数据反演出的边坡土壤含水量后向散射系数,对识别出的5处不稳定区域的形变机理进行分析。结果表明:运用升降轨InSAR可准确识别出库岸边坡的形变情况,研究区最大年平均沉降速率为-92 mm/a;库岸边坡的形变趋势与库水位及土壤含水量后向散射系数变化有着明显的相关性,水库蓄水是致使边坡体加速沉降的主要因素。

Following the commissioning of hydropower stations,frequent water level fluctuations in the upstream reservoir area induced by activities such as reservoir storage and flood discharge,alter the original stability of the reservoir bank slopes.This alteration poses a significant risk of slope instability and damage,thereby impacting the safe operation of the hydropower station and posing potential safety hazards to the surrounding residential areas.To comprehensively understand the deformation of reservoir bank slopes during the impoundment of Wudongde Hydropower Station,sentinel data from ascending and descending orbits were processed using SBAS-InSAR technology for the period from May 2020 to August 2022.This study obtained surface deformation characteristics in the research area.By integrating reservoir water level variations with the SAR-derived slope soil moisture content backscattering coefficient,the deformation mechanisms of five identified unstable areas were analyzed.The results indicate that the use of ascending and descending InSAR accurately identifies the deformation of reservoir bank slopes,with the maximum annual average subsidence rate in the study area reaching-92 mm/a.The deformation trend of reservoir bank slopes exhibits a pronounced correlation with changes in reservoir water levels and soil moisture content backscattering coefficients.Reservoir impoundment is the main factor causing the accelerated settlement of slope.