基于InSAR技术的澜沧江卡贡乡—如美镇段崩滑隐患探测

Detection of potential landslides in the section from Kagong County to Rumei Town of Lancang River based on InSAR technology

澜沧江卡贡乡—如美镇段位于青藏高原东南部,具有海拔较高、河谷深切、地势起伏大、水力资源丰富的特点。该区域地质构造复杂,发育较多高位地质灾害隐患,严重影响下游水电站建设安全。为保证澜沧江下游水电站的安全建设,利用Stacking-InSAR技术探测澜沧江卡贡乡—如美镇段及其干流两侧5 km范围内的隐患点,获取研究区隐患点数量及分布特征,并选取典型隐患点,分析其在时间序列上的形变特征。结果表明:(1)研究区内升轨、降轨影像共探测出崩滑隐患点149处,多具有坡体临空条件好、植被覆盖较少等特点,坡体表面多发育有冲沟,局部多发育浅层崩塌,受风化侵蚀较为严重,结构较为松散;(2)研究区的隐患点类型主要为崩塌和滑坡,共探测出崩塌隐患54处,滑坡隐患95处;(3)研究区滑坡隐患点坡体多发育有局部崩塌现象,且多处于匀速变形阶段,但视线向年均形变速率与累积形变量较大,坡体较不稳定,对澜沧江沿岸居民及下游水电站建设威胁较大。

The section from Kagong Gounty to Rumei Town of Lancang River is located in the southeast of Qinghai-Tibet Plateau,with high altitude,deep-cutting valley,unrolling terrain and rich in hydraulic resources.Because of the complex geological structure in this region,there are many high-position geological hazards,which seriously affect the safety of downstream hydropower station construction.The potential landslides within 5 km of the main stream of the Lancang River from Kagong County to Rumei Town section were detected using Stacking-InSAR technology to ensure the safety construction of hydropower stations downstream.The quantity and distribution characteristics of potential landslides in the study area were obtained,and typical potential landslides were selected to analyze their deformation characteristics in time series.The results show:①A total of 149 potential landslides were detected by ascent and descent orbit images in the study area,with characteristics of free surface development and less vegetation coverage.The landslide surface is full of gully,and shallow collapse occurred in partial areas with serious erosion and loose structure.②The potential landslides in the study area are mainly rockfalls and landslides,with a total of 54 potential rockfalls and 95 potential landslides.③In the study area,most of the potential landslides show multistage sliding trend and are in uniform deformation stage.However,the average annual deformation rate and cumulative deformation in the line of sight are large,indicating that the slope is unstable and poses a great threat to residents along the Lancang River and the construction of hydropower stations downstream.