Gravitational Deformation and Reactivation Mechanism of a Fault-Bounded Slope, Eastern Yanshan Mountains, China

The Nandongzi landslide occurred in the Yanshan region of North China. From 2017, slope has been significantly deformed after several excavations. Field investigations show that is a special toppling deposit does not have basic conditions. deformation mechanism become difficult issue for engineers, attracting attention scientists. Joint, surface, and borehole lithology surveys revealed surface internal structural characteristics slope. structure soft hard interbedded rock proximity fault are dominant factors deformation. failure process can be divided into four stages: initial deformation, compression bending, overlapping, reactivation. In first three stages, triggered by downcutting upstream gully, gravity, differential weathering rocks, which promote dumping final stage, engineering excavations reactivation residual deposits. Monitoring data indicate directly related to rainfall events. Flac 3D was used simulate under natural conditions two results multiple changed runoff slope, led failure. Rainfall promoted back edge landslide, shear from front edge. Our provide new unique understanding spatiotemporal evolution similar toppling-accumulation landslides around study area.