基于极值降雨假设法的城镇地质灾害风险性评价耦合模型研究——以安康市岚皋县官元镇为例

Research on the Coupling Model of Urban Geological Hazard Risk Assessment Based on the Assumption of Extreme Rainfall——A Case Study of Guanyuan Town,Langao County,Ankang City

选取安康市岚皋县官元镇为研究区,以斜坡单元为评价单元,采用信息量-支持向量机耦合模型进行地质灾害易发性评价,根据自然断点法完成易发性分区;基于极值降雨假设法分别计算大雨(35 mm/24 h)、暴雨(75 mm/24 h)、大暴雨(175 mm/24 h)和特大暴雨(250 mm/24 h)4种工况下斜坡的危险性指数,并开展相应工况下危险性区划;采用TOPSIS法计算易损性指数,开展地质灾害易损性分区。综合采用信息量-支持向量机模型、极值降雨假设和TOPSIS法构建研究区风险性评价耦合模型,根据自然断点法划分4种降雨工况的地质灾害风险性分区,将风险区划为极高风险区、高风险区、中风险区和低风险区。

The geological hazard susceptibility of the Guanyuan town was evaluated using the information value-support vector machine coupling model,with slope units as evaluation units.The susceptibility was classified into different zones based on natural breakpoints.The hazard index of the slope was calculated using the extreme rainfall hypothesis method for four different working conditions:heavy rain(35 mm/24 h),rainstorm(75 mm/24 h),heavy rainstorm(175 mm/24 h),and extreme rainstorm(250 mm/24 h).And the corresponding hazard zoning was then conducted.The vulnerability index was calculated using the TOPSIS method,and the susceptibility zoning of geological hazards was carried out accordingly.A coupling model for risk assessment was constructed by integrating the information value-support vector machine model,extreme rainfall hypothesis method,and TOPSIS method.The geological hazard risk zoning was divided into four categories,namely extremely high risk,high risk,moderate risk,and low risk,for the four different rainfall working conditions based on natural breakpoints.