Discrete element analysis on influencing factors of deposit morphology of landslide dam

Abstract

Landslides are the most important reason of landslide dams and can be formed under the action of earthquakes, rainfall, ice and snow melting water. The deposit shape range of a landslide dam has an important influence on the stability evaluation. In this paper, the effects of sliding distance, sliding surface outlet width, sliding surface angle, riverbed inclination angle and valley shape on the deposit shape of landslide dams are analysed systematically by the discrete element method (DEM). The results are as follows: The sliding distance and outlet width have the greatest influence on the dam height. With increasing outlet width and sliding surface angle, the dam length and width linearly increase and decrease, respectively. Sliding distance can effectively control the velocity of the sliding body and then affect the forward dip angle. The angle of the riverbed mainly affects the length of the dam. The regression analysis of dam height, dam length, upstream and downstream absolute dip tangents and deposit angle tangent shows that the mathematical model fits well, indicating that its shape can be predicted. Two parameters, λ and χ are proposed to describe the deposit characteristics of the landslide dam. The influence of the river valley shape is mainly reflected in the fact that the climbing ability of the sliding body increases with increasing bottom width of the river valley. This study is of great significance for predicting the deposit shape of landslide dams and then evaluating safety and provides a reference for further research on the collapse of landslide lakes.

Keywords

• landslide dam
• deposit morphology
• sliding distance
• outlet width
• riverbed angle
• sliding surface angle
• regression analysis