金沙江结合带高位远程滑坡失稳机理及减灾对策研究——以金沙江色拉滑坡为例

金沙江结合带是一条以强烈挤压为主的活动性断裂带,带内经强烈侵蚀切割形成褶皱高山与深切河谷地貌,岩体结构复杂破碎,软弱岩层发育,流域性特大高位地质灾害频繁发生。以金沙江色拉滑坡为例,采用现场调查测绘、多期遥感数据分析、InSAR动态观测、物探、地表位移监测等手段,详细分析了色拉滑坡的基本特征、变形过程、形成机理及发展趋势,并结合金沙江水电开发及特殊地质条件探讨了高位堵江滑坡早期识别与灾害风险管理问题。形成认识如下:色拉滑坡前后缘高差693 m,体积约6520×104 m3,属于典型特大高位滑坡。可分为后部下错变形区(Ⅰ)、中部拉裂变形区(Ⅱ)和前部应力集中区(Ⅲ)3个变形区。受地质构造、地层岩性、降雨与河流冲刷侵蚀等作用影响,失稳模式为多级渐进式破坏,未来滑坡前部发生破坏失稳的可能性较大。采用空天地一体化等先进技术手段,可及时识别高位滑坡变形区域与变形量等信息,为此类流域性灾害链防灾减灾提供科学依据。

Instability mechanism and disaster mitigation measures of long-distance landslide at high location in Jinsha River junction zone: case study of Sela landslide in Jinsha River,Tibet

The Jinsha River junction zone is the active fault one dominated by strong compression. It belongs to the topography of high mountains and valleys, the rockmass structure is complex, and the weak rock strata develop, and the high-location geo-hazards occur frequently. Taking Sela landslide in the Jinsha River as an example, the methods of multi-phase remote sensing data, field investigation and surveying, multi-phase InSAR dynamic observation, geophysical exploration and surface displacement monitoring are used to analyze the basic characteristics, deformation process, development trend and formation mechanism of Sela landslide. Considering the hydropower development and special geological conditions of the Jinsha River, the early identification and disaster risk management of high-position landslides are discussed. The results are as follows: Sela landslide is a typical one with the height difference of 693 m and the volume of about 6520×104 m3. Based on its deformation characteristics, the landslide is divided into three deformation areas. Under the influences of geological structure, stratigraphic lithology, rainfall and river erosion, the instability mode of the landslide is a multistage progressive failure, which is likely to occur in the front of the landslide in the future. The advanced technology such as the integration of space and earth can identify the deformation area and deformation quantity of the high-position landslide in time, and provide scientific basis for the disaster prevention and mitigation of basin disaster chain.