基于GIS的证据权重法的崩塌敏感性分析研究

GIS BASED WEIGHTS OF EVIDENCE METHOD FOR ROCK FALL SUSCEPTIBILITY

证据权重法评价模型作为一个客观的系统,它可以对不同因素的权重值进行计算,且分配权重过程客观,可以区分不同因素对于崩塌敏感性的影响。为了了解不同因素对崩塌的敏感性,本文利用已经发生的崩塌灾害的信息,以湖北省巴东县沿渡河镇为例,选取了106个崩塌点,采用证据权重法,通过ArcGIS软件对坡度、坡向、到断层的距离、到水系的距离、到公路的距离以及地层岩性等6个基本因素进行了敏感性分析,其中随机选取78个崩塌点作为训练集用来建模,另外28个崩塌点作为测试集对评价结果进行检测。分析结果表明:在影响崩塌的6个因子中,崩塌点到公路的距离的敏感性最大;崩塌敏感性高的区域呈线性分布在道路及河流附近,极高敏感区和高敏感性区占整个研究区的15.27%,测试集中有22个崩塌点分布在该区域内,即78.58%的崩塌点被正确评价,与现场调查结果相吻合,所得到的崩塌敏感性图对于防灾减灾工作具有指导作用。

As an objective system,the evaluation model of weights of evidence can calculate the weight values of different factors,assign the weight process objectively,and distinguish the impact of different factors on the sensitivity of collapse.In order to understand the sensitivity of different factors to collapse,this paper uses the information of the collapse disasters that have already occurred and used the example of the Yan Duhe Town in Badong County,Hubei Province as an example.106 collapse points are selected,and the weight method of evidence is adopted.The sensitivity analysis of six basic factors is carried out by ArcGIS software.The six factors include slope,slope direction,distance to fault,distance to water system,distance to highway,and formation lithology.78 randomly selected collapse points are used as a training set for modeling,and the other 28 are used as a test set to test the evaluation result.The analysis results show that the sensitivity of the distance from the collapse point to the highway is the largest.The area with high sensitivity to collapse is linearly distributed near the road and the river.The extremely sensitive area and the high sensitivity area account for 15.27%of the whole research area.There are 22 collapse points in the test set distributed in the area.This is to say that 78.58%of the collapse points are correctly evaluated,which is consistent with the on-site investigation results.The collapse sensitivity map obtained has a guiding role in disaster prevention and reduction work.