Discrete element modeling of the Hongshiyan landslide triggered by the 2014 Ms 6.5 Ludian earthquake in Yunnan, China

Abstract

The Hongshiyan landslide was triggered by the Ms 6.5 Ludian earthquake in 2014 with more than 1200 × 104 m3 of rocks displaced. The landslide deposited entirely on the valley floor, and the landslide dam was eventually converted to a hydraulic structure for a permanent disposal. Despite the importance of material compositions to the slope stability and internal stability of a landslide dam, it was practically not viable and costly to explore the deeply buried materials in field. A 2D discrete element modeling (PFC2D code) was performed in this study to investigate the kinematic behavior of the Hongshiyan landslide. The study aims to provide insights into the material compositions of the landslide dam for future stability evaluations. The simulation results showed that for the landslide sitting in a deep V-shaped valley with constrained movement and steep slip surface gradient, the kinematic behavior was more sensitive to the bond strength (strength of intact rock mass) than the residual friction coefficient (residual friction of detached rock mass). The simulation results also suggested that the rock blocks were scarcely decomposed during sliding, as the material compositions of the landslide dam was primarily controlled by the development of joints and fissures prior to the failure.