A quasi-three-dimensional spring-deformable-block model for runout analysis of rapid landslide motion

• A 3D runout analysis model for landslides is proposed.
• Deformation of sliding body is taken into account.
• Energy transformation in the runout process is analyzed.
• The whole motion process of landslides is visualized here.

Assessment of landslide hazard often requires a good knowledge of the landslide characteristics. To investigate the dynamic runout process of the landslide across a 3D terrain, a quasi-three-dimensional model using spring-deformable-block model is proposed. On the assumption that the motion of landslides is continuous and variable, the sliding body is divided into lots of columns. The model is based on a stability analysis of landslides and allows the deformation of sliding body. Considering the force and moment equilibrium of deformable columns and the principle of conservation of energy, a quasi-three-dimensional sliding body is simplified by a series of deformable blocks with different dimensions. Then, the sliding body acceleration, velocity and displacement formulas are established accordingly. Correlating relatively well with the discrete element method, the present results are satisfactory in describing the dynamic process of landslides and predicting the impact areas of the post-failure sliding body. Finally, the present model is applied to analyze the sliding time, the maximum velocity and displacement of the sliding body of Jiweishan landslide in Wulong, Chongqing Southern China. When comparing with distinct element method, the model shows generally good agreement with them.