Numerical simulation of rainfall-induced debris flow in the Hongchun gully based on the coupling of the LHT model and the Pudasaini model

Numerical simulation is an important approach to reproduce debris flow and can help in predicting and assessing the risks of debris flow. In this paper, the landslide hydrodynamic triggering (LHT) model and the Pudasaini model are adopted to simulate the dynamic process of debris flow. The LHT model can reflect the dynamic volume change of shallow landslides due to precipitation and determine the starting location and the starting volume of the debris flow. The Pudasaini model calculates the volume change of the debris flow in the motion process depending on the initial and boundary conditions. The debris flow event that occurred on August 14, 2010, in the Hongchun gully was chosen as an example. The simulation results indicated that the maximum change in landslide volume occurred near 3:00 on the 14th, which corresponds to the actual start time of debris flow. The area and the volume of the predicted deposition zone are slightly greater than the observed values. The high global precision indicates that the simulation is reliable and appropriate for the observation. This means that linking the LHT model to the Pudasaini model can simulate formation, motion, and deposition process of giant debris flow in the Hongchun gully. This is an efficient method for simulating debris flow under rainfall conditions.