Technology And Method Of Refined Risk Assessment For Geo-hazards In Mountainous Cities And Towns

In recent years,the frequent geological disasters in mountainous cities and towns have severely restricted the development of mountainous cities and towns.The risk control of urban geological disasters in mountainous areas has become a major problem for the prevention and reduction of disasters in mountainous cities and towns.In this regard,a great deal of geological hazard risk assessment has been carried out at home and abroad.However,the accuracy and practicability of the current geological hazard assessment are not as good as expected.There are still some areas for further exploration and study.In this paper,the definition of geological hazard risk assessment,time and space scale,evaluation model and other key problems are deeply analyzed.Using high precision remote sensing image and GIS technology,the three level spatial scale of geological calamity around Yiliang County,the geological calamity around the town of Luo Ze River and the landslide of peanut land single landslide,combined with two time scales of daytime and evening.In order to improve the accuracy and practicability of the risk assessment,the technical flow of the risk assessment of the urban geological disasters in the mountainous areas is summarized,which has been completed in three regions with different spatial and temporal scales.The specific contents and conclusions are as follows:(1)based on ArcGIS,three spatial scale geological hazards risk,vulnerability and risk assessment map of 1:10000 Yiliang County,1:2000 Luo river market town and 1:2000 peanut landslides were completed in two periods of day and night.(2)summing up the techniques and methods of meticulous risk assessment for geological hazards in mountainous cities and towns.Based on GIS technology,using high precision remote sensing image,by analyzing the time and space of risk assessment,using the information quantity method to evaluate the risk,the vulnerability assessment is carried out by the generalized objective function method,and the technological process of evaluating the geological hazard of mountainous cities and towns in the consideration of space-time scale is explored.(3)Comparative Study on risk assessment of geological hazards at different spatial scales is realized.In this paper,a comparative study on the risk assessment of geological hazards in three different spatial scales of Yiliang County,Luo Ze River and peanuts landslides is carried out by using the method of fine risk assessment of urban geological disasters in mountainous areas.The risk location of geological hazard is large to small in spatial scale and rough in risk assessment.(4)improving the accuracy of risk assessment.By means of remote sensing interpretation,field investigation and field visit,the data of disaster bearing body and disaster induced body are obtained in detail,and the quantitative construction of the database of disaster bearing bodies in the risk area is realized.(5)improve the effectiveness of risk assessment.On the basis of data analysis of disaster induced bodies and disaster bearing bodies in the study area,the period of risk assessment of urban geological disasters in mountainous areas is clarified,and the evaluation index system of geological hazard risk is constructed,and risk evaluation is carried out in two time periods in the daytime and night to improve the effectiveness of risk assessment.