Development Characteristics and Stability Evaluation of the Shadingmai Large-scale Ancient Landslide in the Upper Reaches of Jinsha River,Tibetan Plateau
The Shadingmai ancient landslide is located in the upper reaches of the Jinsha River.The Degong-Shedan Fault from the Jinsha River Fault system passes through the front part of the landslide,causing a large scale of rock fractures.Combined with the effects of regional rainfall and human activities,the landslide experi-ences an intense deformation,posing a risk of unstable sliding.This causes a serious threat to the lives,proper-ties of residents,and critical transportation in the upstream region of the Jinsha River.To investigate the key is-sues such as the developmental characteristics and stability of the Shadingmai ancient landslide,this study con-ducted remote sensing interpretations,InSAR deformation monitoring,rainfall analysis,and numerical simula-tion of landslide stability for the landslide.The study investigated the current deformation characteristics of the landslide and explored its stability under different conditions.The research results indicate that the Shadingmai ancient landslide is approximately 2,100 m long and 1,300 m wide,with a thickness of approximately 15-20 m.Its volume ranges from 2,180 x 104 to 2,900 x 104 m3,making it a super-large accumulation landslide.In terms of its spatial distribution,it can be divided into three regions,as the ancient landslide rear edge region(Ⅰ),the ancient landslide accumulation region(Ⅱ),and the strong deformation region(Ⅲ),which further includes two reactivated deformation zones(Ⅲ1 and Ⅲ 2).The main deformation phenomena of the landslide in-cluded tensional cracks,building fissures,steep displacement faults,and localized collapses.Based on SBAS-InSAR monitoring results,the maximum surface deformation rate reaches to-51.88 mm/a.Combined with the regional rainfall data,the cumulative deformation of the landslide exhibits a'step'growth pattern.Heavy rain-fall is one of the significant factors influencing the deformation of the landslide mass.The stability calculation of the landslide using FLAC3D shows that the deformation mode is characterized by retrogressive deformation.Under natural conditions,the landslide is in a relatively stable state with minimal slope deformation.However,under extreme heavy rainfall conditions,the landslide becomes unstable,exhibiting tension and shear failures,with the sliding surface penetrating and causing overall instability and significant hazards.
upper reaches of the Jinsha RiverShadingmaiancient landslidedeformation monitoringnu-merical simulation
国家科技期刊平台
NSTL
万方数据
维普
