PERFORMANCE OF FRONT VELOCITY ON SLOPE IN A 1D RAPID DEBRIS FLOW NUMERICAL MODEL

Tóm tắt

Landslides and debris flows are among the most destructive natural hazards, posing serious threats to human life, infrastructure, and socio-economic development. Rapid debris flows occurring on steep slopes are particularly dangerous due to their high mobility and destructive front velocity. Accurate prediction of the front velocity, the leading edge speed of the moving mass, is critical for hazard assessment, runout estimation, and engineering countermeasures. This study develops and evaluates the one-dimensional (1D) numerical model to investigate the performance of front velocity on slopes for rapid debris flows governed by Coulomb-type rheology. The governing equations are derived from depth-averaged nonlinear shallow water formulations, modified to account for slope gradients and internal frictions. The model applies a hybrid finite difference–finite volume scheme for spatial discretization, ensuring numerical stability and accuracy in capturing steep slope dynamics. Numerical experiments are conducted across a range of slope angles and rheological parameters, which generate 16 scenarios, to analyze their effects on debris front velocity values. Results indicate that the front velocity is highly sensitive to small bottom slope angles under different internal friction angles. A linear relationship between debris front velocities and bottom slope angles, as well as a nonlinear relationship between simulation times, debris lengths and bottom slope angles are identified in this study. For future research, more rheological models should be incorporated into the resistance terms, and the approach should be extended to two-dimensional models.