Abstract: Numerical simulation of the dynamic process of Nomash River debris flow was carried out using the continuous theory method in this study. Three different entrainment rate models were applied in the continuous theory model, and the HLLC approximate Riemann solution was used to calculate the interface flux of the control unit of the finite volume numerical discrete. Calculation results of disaster scope and motion time were in good agreement with the actual disaster situation, which verified the correctness and validity of the simulation. Then, the final accumulation depth, motion velocity and erosion depth were analyzed and discussed. The results showed that the average depth and maximum depth of final accumulation obtained using McDougall entrainment model were close to those measured. The maximum velocity obtained using the Medina entrainment model at each time was the largest, followed by the result of McDougall entrainment model and the result of Pitman entrainment model. The erosion depth distribution using McDougall erosion model was more continuous, and the maximum value of 8.1 m was close to the estimated value of 8 m. The erosion depth results obtained using Medina erosion model and Pitman erosion model were more dispersed, and their maximum values were 10.9 m and 8.6 m, respectively.

Key words: debris flow, entrainment of path material, dynamic process, model equation, numerical simulation