Numerical simulation of debris flow runout using Ramms : a case study of Luzhuang Gully in China

This study proposes a comprehensive method, which consists of field investigation, flume test and numerical simulation, to predict the velocity and sediment thickness of debris flow. The velocity and sediment thickness of the debris flow in mountainous areas can provide critical data to evaluate the geohazard, which will in turn help to understand the debris runout. The flume test of this debris prototype can provide friction coefficient and viscosity coefficient which are important for numerical simulation of debris flow. The relation between the key parameters in the numerical modelling using the Voellmy model and debris-flow rheology is discussed. Through simulation of a debris flow that occurred in Luzhuang gully, it is observed that the debris flow runout determined by the Voellmy model was well consistent with that obtained from field investigation and flume test, demonstrating the effectiveness of this study. The relationship between the Voellmy model and debris flow runout is also proposed.