1.中国地质科学院;2.中国地质调查局 水文地质环境地质调查中心;3.中国地质调查局 西安地质调查中心;4.甘肃省地质环境监测院
1.Center for Hydrogeology and Environmental Geology,CGS;2.Xi '3.'4.an Geological Survey Center of China Geological Survey;5.Geo-Environment Monitoring Institute of Gansu Province,Lanzhou
[Objective]Gansu Province is one of the regions with the largest number of potential geological hazard points, the highest frequency of occurrence,and the most difficult risk prevention in China. To improve the level of urban geological hazard risk prevention and control in this region, the key to disaster prevention and mitigation is to scientifically and reasonably construct the "point-surface dual control" mode of geological hazard risk. [Method]Taking Longlin Town, Lixian County, Longnan City as an example, based on on-site fine survey and mapping, multi-phase remote sensing data modeling, indoor test, and numerical simulation analysis, the paper expounds the technical framework process of geological disaster risk management and control in typical cities and towns based on six steps, namely, geological disaster risk identification, disaster mode research, risk analysis, vulnerability evaluation, risk evaluation and risk prevention and control countermeasures, This paper introduces the semi-quantitative risk assessment process of urban risk slope, forms the quantitative risk assessment method of single geological hazard based on dynamic process, and preliminarily discusses the double-control mode of geological hazard risk. [Results]1) The main types of geological hazards in the study area are landslide and debris flow, with a total of 71 hidden danger points of geological hazards developed, 15 of which directly threaten the safety of people's lives and property. The three types of landslide hazard models are summarized and the geological early identification signs are established; (2) The geological hazard risk zoning of different precipitation frequencies (5%, 2%, 1%) based on the disaster dynamic process shows that under different precipitation frequencies, 75.23% of the regions always maintain low risk, 24.38% of the regional risk level increases with the reduction of precipitation frequency, and 0.39% of the regions always maintain high risk; (3) Based on the results of risk assessment, the risk source control content, risk prevention and control technology, and engineering and non-engineering measures for disaster prevention and control that can be used for disaster reduction in market towns and specific disaster points are proposed. [Conclusions]Relevant research can provide technical support for disaster prevention and reduction in complex mountainous cities and towns, land space planning control, and use of the control, and has certain reference significance for the formation of a dual control system of "hidden danger points + risk areas" for geological disasters of different scales.