RELATIONSHIP BETWEEN MOVEMENT CHARACTERISTICS OF NON-HOMOGENEOUS DEBRIS FLOW AND PEAK FLOW

Abstract

The prediction and evaluation of the change characteristics of non-homogeneous debris flow are an important content of debris flow control project planning and early warning and forecasting system construction. They are also a key issue that needs to be improved in the field of debris flow. By sorting out and analyzing the measured data of the mud level and velocity of the debris flow, a prediction model of the characteristic value of the non-homogeneous debris flow movement is constructed. Based on the previous results, the model can distinguish the change characteristics of the debris flow movement in the study area with fewer factors. Taking the mud-rock flow in Xiahuyang Gully, Lixian County, Longnan area as an example, the FLO-2D fluid model is used to simulate the movement characteristics of debris flow under precipitation conditions of once in 50 years(2% frequency) and once in 20 years(5% frequency). The results show that when the specific weight gravity of debris flow is 1.83t ·m-3, the characteristic value of debris flow movement in Xiahuyang Gully in 20 years is the smallest and the difference is not significant. When the specific weight gravity of debris flow is 1.97t ·m-3, the characteristic value of debris flow movement in Xiahuyang Gully is once in 50 years the biggest and the difference is huge. When the flow of debris flows of different scales reaches the peak, they all produce larger mud level depth. The simulation results of the debris flow movement characteristic value are further combined with the actual measured cross-sections for inspection and analysis. The peak flow rate of the debris flow event is inferred and is in good agreement with the actual situation, indicating that the results calculated by the prediction model of this paper are reliable. The results in this paper can provide a reference for the construction of debris flow disaster prevention and mitigation and debris flow monitoring and early warning demonstration areas.