Development and evolution of deep-seated toppling landslide by rapid river downcutting

A large-scale deep-seated toppled rock mass was located upstream of the Lancang River. The toppling deformation mechanism of layered steeply dipping rock masses and its evolution process into landslide were studied in this work by using the base friction experiment and the PFC numerical simulation. The deep and steep landform with a slope height exceeding 250 m and slope angle exceeding 50 degrees caused by the rapid and continuous downcutting of the river was an essential condition for the formation of deep-seated toppling deformation. Three early warning signals, including the emergence of numerous toppling fracture zones, intensive compression of rock masses in the front part of the slope, and shearing deformation along the toppling fracture zones, should be considered as indications of the evolution of toppling deformation into a landslide. Destruction of the frontal part of the toppled rock masses caused the accelerated evolution of the slope into a landslide. The slip zone was formed mainly by tracing the toppling fracture zones.

Automated summary

In this study, the toppling deformation mechanism of layered steeply dipping rock masses and its evolution into a landslide were investigated using experiments and simulations. It was found that a large-scale toppled rock mass was located upstream of the Lancang River, with the rapid downcutting of the river forming the steep landform that was essential for the formation of deep-seated toppling deformation.