Analysis of the Cause Mechanism and Blockage Risk of the Jingsha River Baige 11.29 Landslide

The Baige Landslide of Jinsha River experienced two river blocks in October and November 2018. The remaining landslide bodies K1, K2, and K3 at the rear edge are large in scale, posing a possibility of sliding and blocking the river again. From November 29 to November 30, 2022, significant deformation occurred in part of the block, indicating unfavorable stability and safety conditions. In response to this new hazard, an engineering geological survey, geophysical exploration, and surface displacement monitoring were conducted on the residual body of Baige landslide. Historical deformation and failure phenomena as well as potential instability scales of K1~2 and K1~3 residual bodies were identified. Additionally, a PFC3D particle discrete element numerical simulation technology was used to establish a ball~wall model for predicting the motion process and accumulation pattern of possible instabilities at two locations. The "four~edge platform calculation" method was employed to scientifically evaluate the risk of the residual body blocking the river. The results indicate that the K1~3 block is currently in a creep stage with significant deformation showing an overall downward trend. The southern K1~2 block exhibits minimal deformation with low overall failure probability. However, under extreme circumstances where an overall slide of K1~3 leads to instability in K1~2 blocks resulting in their combined damage, a barrier body with a dam height of approximately 46m could form on Jinsha River presenting certain risk of landslide~induced river blockage.