Stability Evaluation of Massive Landslides Using Ensembled Analysis of Time-Series InSAR and Numerical Simulation along the Yellow River, Northwestern of China

Abstract

Loess landslides are a major geological disaster in the southeastern Qinghai Province, causing huge economic losses and casualties. The particularity of loess determines the disaster initiation mechanism, disaster mode, genetic mechanism, and complexity of the evolution process. This paper studies the deformation and stability analysis of the Quwajiasa large-scale multislip loess landslide in the Yellow River Basin from the perspective of field investigation, Interferometric Synthetic Aperture Radar (InSAR) monitoring, and numerical simulation. This study determines the deformation characteristics and genetic mechanism of the landslide through on-site field investigation, then quantitatively evaluates the overall deformation of the landslide using InSAR monitoring, locates the strong deformation area, and finally determines the control relationship between the two sliding surfaces on the landslide deformation using FLAC3D numerical simulation, obtaining the stability coefficient of the two sliding surfaces. The landslide is divided into seven engineering geological zones. The deformation history of the landslide is studied using InSAR technology. Results show that the landslide can be divided into significant deformation areas and no significant deformation areas. Two strong deformation areas are found. The FLAC3D numerical simulation results show that the deformation and stability of the right side of landslide are controlled by sliding surface 1, and the deformation and stability of the left side are controlled by sliding surface 2. The landslide is in an unstable state overall. The research done in this paper proposes a basis for the treatment of the Quwajiasa landslide.