Integrated Dynamic Model for Numerical Modeling of Complex Landslides: From Progressive Sliding to Rapid Avalanche

Landslides are one of the most common catastrophic mass flows in mountainous areas. The occurrence of fragmentation leads to the evolution of the integrity and stiffness of the sliding mass. The changes in internal composition caused by basal erosion and entrainment make the dynamic evolution of landslides more complex. To consider these complex processes, physics-based dynamic models are often used to analyze the dynamic characteristics of landslides. However, the proprietary assumptions of dynamic models often limit their application to complex events. A single dynamic model is often not competent for the analysis of landslides with evolving dynamic characteristics. In this study, two dynamic models are effectively integrated according to the evolving characteristics of the landslide. The common effects of basal erosion and entrainment are also considered. The maximum sliding velocity, accumulation range, and erosion depth characteristics of this integrated dynamic model are more consistent with the field than those of the single dynamic model. Under the terrain conditions of this study, within a few seconds of the triggering stage, if the occurrence of disintegration is advanced by 2 s, the maximum impact area will increase by about 3.1% to 4.1%, and the maximum kinetic energy will increase by more than 20%. Simulation results indicate that the changes in the integrity of the landslide body significantly affect the evolution of subsequent landslide dynamic characteristics.