西藏易贡高位远程滑坡研究进展与展望

Research progress and prospects of the giant Yigong long run-out landslide,Tibetan Plateau,China

高位远程滑坡指剪出口高、滑动距离长、体积大和速度快的滑坡,具有强动能、强烈碎屑化-流体化、铲刮效应等特征,滑坡及其诱发的灾害链对人类生命财产安全、路桥基础设施、水利水电工程等危害巨大。在遥感解译和野外调查的基础上,总结了2000年西藏易贡高位远程滑坡的研究进展,分析了滑坡启滑机制、体积、运动速度、堰塞湖体积、溃坝机制等,进一步揭示了内外动力耦合作用是西藏易贡高位远程滑坡的主要影响因素,以及该滑坡具有溯源侵蚀复发型的周期性启滑机制。基于GIS与高精度DEM进一步核算了易贡高位远程滑坡的体积,认为滑源区崩滑体体积约9225×10^(4)m^(3),滑坡堆积体体积约为2.81×10^(8)~3.06×10^(8)m^(3),其中堆积体体积与国内外研究的认识基本一致。易贡滑坡崩滑源区还发育2个潜在失稳区,潜在崩滑体方量约1.86×10^(8)m^(3),一旦失稳可能再次形成滑坡-堵江-溃坝灾害链,危害巨大,故提出了进一步加强易贡高位远程滑坡潜在崩滑体稳定性研究、灾害链流域性影响范围预测和监测预警等建议,对于指导该区正在规划建设的铁路、水利水电等重大工程建设和城镇防灾减灾具有重要意义。

Long run-out landslide is a landslide with high shear outlet,long sliding distance,large volume and high speed,which is characterized by strong kinetic energy,strong fragmentation-fluidization and entrainment effect.The landslide itself and its induced hazard chain are great harm to human life and property safety,road and bridge infrastructure and water conservancy and hydropower projects.Based on remote sensing interpretation and field investigation,this paper summarizes the research progress of the giant Yigong long run-out landslide in Xizang in 2000.It also delves into the initiation mechanism,landslide volume,movement speed,dammed lake volume and dam failure mechanism of Yigong landslide.Furthermore,it reveals that internal and external dynamic coupling is the main influencing factor of the Yigong landslide and considers that the landslide has periodic sliding mechanism of retrogressive erosion recurrence type.In additon,this paper calculates the landslide volume based on GIS and high-precision DEM and reveals that the landslide volume in the landslide source zone is about 9225×10^(4)m^(3).The landslide accumulation volume is about 2.81×10^(8)~3.06×10^(8)m^(3),which is close to the domestic and international research.There are two potential instability rockmass in the landslide source zone of Yigong landslide,with a total volume of about 1.86×10^(8)m^(3).Once the two potential instability rockmass are unstable,the hazard chain of landslide-river blockage-dam break might be formed again and cause great harm.This study concludes by proposing research directions to further research the stability of the potential landslide of the Yigong landslide,predict the basin influence range of the hazard chain,establish the monitoring and early warning system.These suggestions have important guiding significance for the construction of major projects such as railway and hydropower projects being planned and constructed in this area,as well as for urban hazard prevention and mitigation.