Run-out Effects of Debris Flows Based on Numerical Simulation

Debris flows are a common natural disaster in mountainous areas and often cause severe casualties and property loss. Debris-flow run-out effects analysis can provide an idea of the spatial risks posed to the downstream area of a debris flow, which is extremely important for local populations’ lives, disaster mitigation and planning the layout of economic construction. The objective of this study is to develop a new method to quantify debris flow run-out effects by combining debris flow simulation results and data for different types of land use within the inundated area. After a three-dimensional numerical simulation platform was established, the numerical simulation method was applied as a modeling tool to simulate the inundated areas and final buried depths under rainfalls with different return periods. The simulated result for flow depth under a 100-year return period rainfall event was validated based on field measurements. Finally, the debris-flow run-out effects under different return periods were analyzed by combining the simulation results and land use data. The proposed method can enhance the accuracy of debris-flow spatial risk assessment and has great value for application.