Risk Assessment Model for Disasters in Villages

Abstract

Disaster prevention and mitigation works of landslide have been getting more and more attention with the increasing frequency of landslide development and the great threat to the lives and properties of human beings. And the risk evaluation of landslide is one of the critical works. Fuzzy comprehensive evaluation is a fairly common method of researching the risk evaluation of landslide. Therefore a multi-hierarchical fuzzy comprehensive evaluation model for risk grade of landslide was established based on AHP (analytic hierarchy process), which had three hierarchies. The first hierarchy was risk grade evaluation of landslide, the second hierarchy included hazard and calamity, and the third hierarchy included landform, terrain condition, engineering environment, capacity for resisting natural disasters, and value. And fifteen evaluation indexes were chosen according to the research results of many scholars and the analysis of the actual survey, including gradient, slope height, slope shape, slope structure, friction angle, cohesive force, water permeability, underground water, annual precipitation, engineering activities, population structure, precautionary measure, threating population, damage area and land types. After determining membership functions, memberships of each evaluating index could be calculated. Analytic hierarchy process is widely used in fuzzy comprehensive evaluation because of its rationality. And the weights of the fifteen evaluation indexes in the model were assigned by method of AHP, which perfectly combines the mathematical model with the experience of experts when calculating the weights of evaluation indexes. The result was that each weight was [0.491 0.195 0.118 0.195 0.323 0.323 0.207 0.146 0.500 0.500 0.333 0.667 0.500 0.250 0.250]. To test the actual application effect of the model, Songjia landslide in Muyu Town was chosen as the demonstration project because of its typicalness. And the risk evaluation of Songjia landslide included hazard evaluation, calamity evaluation. According to the actual data, the risk grade of Songjia landslide could be evaluated with the multi-hierarchical fuzzy comprehensive evaluation model. As the evaluation result showed, the hazard grade of Songjia landslide was Ⅲ level and the calamity grade was Ⅱ level. Therefore the risk grade of Songjia landslide was Ⅲ level based on the matrix of risk grade, with high risk. And the evaluation result almost met the actual situation. Consequently the research achievement can be applied to the risk grade evaluation of landslide and provide a reference for the work of landslide disaster prevention and mitigation. 

Keywords:

landslide; risk grade; multi-hierarchical; fuzzy comprehensive evaluation; AHP