Practical application of the coupled DDA-SPH method in dynamic modeling for the formation of landslide dam

Abstract

Landslides along river margins can cause permanent or temporal landslide dams and dammed-lakes, threatening people’s life and properties. Investigation of the formation process for the landslide dam is crucial for emergency response and mitigation planning. However, the formation process modeling for a practical case usually involves large scale and complicates geometry. To overcome the computation complexity and promote efficiency, a series of practical techniques have been proposed. Firstly, an Open Channel Model with Steady Flow (OCMSF) has been developed to naturally produce a river flow. Then, a three-stage simulation strategy has been proposed to fulfill the large-scale practical modeling. In specific, stage 1 generated a steady open channel flow using SPH method. In stage 2, the DDA method is used to simulate landslide movement until the mass reaches the river. In stage 3, the formation process with landslide-river interaction is realized using a coupled DDA-SPH method. The formation process of the Yangjiagou landslide dam was selected as the practical application. Simulation results showed the Yangjiagou landslide reached the river with a front velocity of 22 m/s in around 8 s and formed a dam with estimated volume of 500,000 m3, which is consistent with the site investigation. It is thus demonstrated the applicability and performance of the coupled method and numerical techniques in modeling practical landslide dam case.