广西田阳县地质灾害易发性分区与评价研究

Research on zoning and evaluation of geological disaster susceptibility in Tianyang county, Guangxi

为了制定田阳县地质灾害防治规划,本文研究采用遥感、地面调查、测绘、物探、钻探等勘查手段对田阳县进行1:50 000的地质灾害详细调查工作,在此基础上采用了层次分析法对研究区进行地质灾害易发性区划和评价。其具体做法是将地质灾害易发性分区评价做为目标层,选择地质灾害的发育特征、基础地质条件和诱发因素构成准则层即二级评价因子,并选取地质灾害发育密度、地质灾害易发村屯密度、地貌类型、地形坡度、风化土层厚度、地质构造、工程地质岩组、水文地质条件、人类工程活动、降雨构成三级评价因子;同时根据田阳县地质灾害形成因素的主次控制条件和各评价因子对不同类型的地质灾害影响程度,确定出各评价因子的权重值,最后采用综合指数法并结合MAPGIS软件的空间叠加统计分析功能,将田阳县的地质灾害易发性进行区划,共分出4个大区16个小区。

In order to formulate the geological disaster prevention and control plan forTianyang County, the detailed investigation of 1:50000 geological disasters in Tianyang County were carried outby means of remote sensing, ground survey, surveying and mapping, geophysical exploration and drilling. Base on the survey, the analytic hierarchy process was used to regionalize and evaluate the susceptibility of geological disasters in the study area. The specific method is to take the zonal evaluation of the susceptibility of geological disasters as the target layer, and select the development characteristics, basic geological conditions and inducing factors of geological disasters to form the criterion layer, that is, the second-level evaluation factors.The three-level evaluation factors are selected as following: the development density of geological disasters, the density of villages prone to geological disasters, geomorphic type, topographic slope, the thickness of weathered soil layer, geological structure, engineering geological rock group, hydrogeological conditions, human engineering activities and rainfall. At the same time, the weight value of each evaluation factor is determined according to the primary and secondary control conditions of geological hazard formation factors in Tianyang County and the influence degree of each evaluation factor on different types of geological hazards. Finally, the comprehensive index method and the spatial superposition statistical analysis function of MAPGIS software are used to divide the susceptibility of geological disasters in Tianyang County. The whole county is finally divided into 4 regions and 16 districts.