Stability study of high steep slopes at the head section of the Water Diversion Project from Dadu River to Minjiang River

Abstract

Aiming at the stability issues of high steep slopes at the initial section of the Water Diversion Project from Dadu River to Minjiang River(Yindajimin Project) located on the eastern edge of the Qinghai-Xizang Plateau in the Hengduan Mountains area, long-term series of ground deformation monitoring using Synthetic Aperture Radar Interferometry(InSAR) technology were employed to identify potential instability areas. High-resolution three-dimensional terrain data of the slopes were also acquired using Unmanned Aerial Vehicle(UAV) photogrammetry. Stability analyses under potentially adverse conditions were then conducted combining Limit Equilibrium Method and Finite Element Strength Reduction. The results demonstrate that the continuous surface deformations captured by SBAS-InSAR correlate spatially with local collapse of loose rock masses, indicating good stability of the slopes under current conditions. However, earthquake and rainfall activities significantly reduce the safety factor and may induce shallow overall sliding. Nevertheless, due to the favorable physico-mechanical properties of the rock materials in the study area, the slopes are expected to remain stable even under extreme conditions. The combined approach of satellite radar observation and numerical simulation provides a valuable reference for the stability assessment of similar high steep slopes in other hydroelectric engineering projects.

Keywords

Yindajimin Project / High Steep Slopes / Stability Analysis / Synthetic Aperture Radar / Limit Equilibrium Method / Strength Reduction Method