Hazard assessment of debris flow in Guangxi, China based on hydrodynamics mechanism

Abstract

This paper aims at developing a mathematical model of hazard assessment of debris flow (DF) by applying hydrodynamics mechanism (HM) in the judging of DF starting. On the basis of HM, finite-volume method has been used and the flow passages have been classified into ground channel, river channel, and overflow channel; hence, the simulating result of depth distribution could be adopted to judge DF starting by comparing with DF critical depth. Meanwhile, rainfall, terrain, geology, vegetation, and population have been selected as the impact factors, and normalization method has been utilized to calculate the five factors’ weights based on the synthesis of analytic hierarchy process and fuzzy-weighting method. Combining the impact factors’ weights with its digitized results, respectively, thus, DF hazard assessment could be achieved with the programming calculation of Fortran. Indeed, the assessment results have been validated by comparing with the statistical result of geological hazards distribution in Guangxi and the Quanzhou County Debris Flow Event in 2011. The validation results show that the mathematical model is reliable, and it is feasible in the hazard assessment of DF.