基于FLO-2D的泥石流灾害风险评价——以麦多沟泥石流为例

Risk assessment of debris flow hazard based on FLO-2D:A case study of debris flow in Maiduo Gully

针对4种极端降雨工况下泥石流威胁范围和存在的潜在风险,以单个建筑物作为评价单元,对西藏察雅县城麦多泥石流灾害进行风险评价,包含泥石流危险性分区、易损性分析和风险评价3方面主要内容。文中阐述了整个精细化风险评价的流程:首先基于实地获取的无人机三维地质模型,利用FLO-2D软件模拟麦多沟在4种极端降雨工况下(10%、5%、2%、1%)泥石流暴发过程,对其潜在威胁区进行危险性分区;基于实地走访调查所得数据,进行影响范围内建筑物和人口的易损性分析;将危险性和易损性归一化处理,以单个建筑物作为评价单元,经过ArcGIS平台叠加运算,最终得到研究区建筑物风险和人口风险分区。评价结果可为当地地质灾害、风险管控工作提供科学参考依据,评价流程对今后泥石流灾害的精细化定量风险评价有一定的借鉴意义。

In view of the spatial scale of threat and potential risks caused by debris flow under four extreme rainfall conditions,risk assessments of debris flow hazard in Maiduo Gully,Chaya County,Tibet were carried out,using a single building as an evaluation unit. Assessments include the risk division,vulnerability analysis and risk assessment of debris flow. This paper describes a whole workflow of a refined risk assessment. Firstly,based on a three-dimensional geological model acquired from UAV,the FLO-2D software was used to simulate the process of debris flow outbreaking in Maiduo Gully under four extreme rainfall conditions(10%,5%,2%,1%),and the risk zones were divided. Then,analyzed the vulnerability of buildings and population in the affected area according to on-site data. After that,took a single building as the evaluation unit,risks and vulnerability were normalized,and to eventually get the risk zones of building and population in study area,overlay analysis was applied on ArcGIS Desktop.These evaluation results are able to provide scientific reference to the works of local geological disasters and risk control,and the evaluation workflow can be used as a reference for future refined quantitative risk assessments of debris flow hazard as well.