重庆万州区地质灾害危险性分区及评价

Risk zoning assessment of geological disaster in Wanzhou area,Chongqing City

地质灾害危险性评价是地质灾害灾情评估的重要内容和基础,其影响因素具有复杂性、相互关系及模糊性特点。文章以重庆市万州区为例,进行地质灾害危险性分区及评价研究,实施过程分为3步:首先遴选出灾害体、地表坡度、森林植被、水文地质、岩性、地表高程和库水位7个滑坡、危岩地质灾害的影响因子;其次采用综合评价法获取危险性指数。其评价模型为Ii=∑7Ki·Xi,式中Ki为各选取因子作用权重系数,通过层次分析法(APHi=1法)及灰色聚类法求出其平均值。Xi为各选取因子的次级分级赋值,采用Dephel法赋值,每一权重系数作用下取相应值,将示范区用等面积网格法通过GIS系统空间因子叠加获得危险性指数等值线图;最后根据危险性指数进行地质灾害危险性分区,分为5级,据此进行地质灾害危险性评价。用多因子叠加模型分析地质灾害危险性,其结果符合实际情况。

Risk assessment of geological disaster is quite an important topic and base in geological disaster assessment, whose relative factors are complicated and fuzzy. Taking geological disasters in Wanzhou area as an example, authors have made risk zoning and assessment of geological disaster in this paper, which include three steps, the first step is to select seven risk factors i.e. disasters, surface slope, vegetation, hydrogeological conditions, rock property, altitude and water level of the Three Gorges Reservoir. The second step is to obtain risk index using the synthetic assessment method whose model is I_i=∑7i=1K_i\5X_i, in the formula weight K_i is the weight to every factor calculated through grey assemble theory and the Analytical Hierarchy Process (AHP), while X_i belongs to sub-grade value of every factor. Then risk index iso-chart can be obtained through factors coupled by GIS system to every net in the area. The third step is to make risk zoning that include four grades and make risk assessment of geological disaster in the area. Results of risk of geological disaster are consistent with status in-situ in multi-factor superposition model, which are valuable in the monitoring and controlling of geological disaster in Wanzhou area.