基于SHALSTAB模型的地质灾害易发性动态评价

为解决东部沿海地区台风暴雨型地质灾害易发性问题,基于浙江飞云江流域地质灾害调查成果,利用频率比及信息量模型选取相对高差、坡向、坡形、工程地质岩组、断层、地表覆盖类型、稳定性(SHALSTAB模型)7个背景因子,采用层次分析法确定各因子权重,考虑无降雨和百年一遇极端降雨两种工况,运用综合指数法对浙江飞云江流域进行地质灾害易发性评价.结果表明:该模型是致灾土体分布区定量模型和基岩区统计模型的结合,符合该区域成灾规律.考虑极端降雨因素后,易发等级逐次增加,高易发区面积增加84%,中易发区面积增加42.8%,可实现地质灾害易发性在不同工况下的动态评价.

Dynamic assesment of geohazard susceptibility based on the SHALSTAB model

Based on the investigation results in Feiyun River Basin, Zhejiang Province, this study employed seven background factors in order to evaluate the susceptibility of typhoon-storm geohazards in eastern coastal areas in China. Seven background factors incude relative elevation, slope aspect, slope curvature, engineering rock formation, distance from faults, surface covering, slope stability(SHALSTAB model) which were defined using frequency ratio and information content model. Based on the weight of each factor determined by the analytic hierarchy process(AHP) method, with the consideration of the two climates consisting of no rainfall and one hundred year extreme rainfall, basin-scale geohazard susceptibility was evaluated by the comprehensive index method. The model is a combination of quantitative model and statistical model of the soil distribution area of disaster-causing soil, which conforms to the law of disaster-making in this region. The results show that after considering extreme rainfall, susceptibility grade increases successively, with the high-susceptible area increasing by 84% and the medium-susceptible area by 42.8%, suggesting that the dynamic evaluation for the susceptibility of geohazards under different operating conditions can be realized.