ANALYSIS OF HAZARD ZONE AND COUNTERMEASURES USING COMPUTATIONAL SIMULATION OF DEBRIS-FLOW DIFFUSION

Debris flow is one of the life threatening natural hazards frequently occurring during heavy rain or typhoon. It is generally defined as a mixture of solid particles of various sizes and water. Due to high uncertainty inherited in the phenomena, the problem has not been well investigated and still remains with many unanswered issues. Recent experimental studies to understand the debris flow have revealed some of its nonlinear behavior in viscosity and soil-moisture content; however, computational analysis is still in its early stage. This paper presents a numerical study of computational fluid dynamics application to simulate the debris flow using the open-source code with consideration of multiphase flow of nonlinear viscosity. Based on the previous study showing the potential validity to estimate the debris affecting spatial range on the digital topography, several study regions in Chungcheongbuk-do are modeled, where frequent debris flow damages have occurred or are anticipated. Since the volume of the debris flow nor moisture contents in the soil are known, the parametric investigations are performed for various volume and moisture contents. In addition, different initial locations of the debris flow are tried to identify the most dangerous zone where a computational model for barrier is implemented. As the results, the proposed approach can be utilized to identify the hazardous region in advance and assess the effect of the structural countermeasures.