基于有效降雨阈值的澧源镇滑坡灾害危险性分析

以湖南省澧源镇为例，利用证据权模型和灰色关联度模型分别计算了坡度、地层岩性、斜坡形态、土地利用类型、人类工程活动5个因子二级状态证据权值和一级因子权重；综合2种模型确定全区滑坡易发性指数后，完成基于斜坡单元的全区滑坡易发性区划；根据研究区岩土体类型（碎屑岩类、碳酸盐岩夹碎屑岩类、碳酸盐岩类和松散岩土体类）分组研究不同滑坡发生概率下的有效降雨阈值曲线（I-D曲线）。研究降雨时间为3日、有效强度为22.4 mm/d的降雨工况下各岩土体类型滑坡发生的时间概率。综合时间概率和易发性结果得到澧源镇基于有效降雨阈值的滑坡灾害危险性区划图。研究结果表明:澧源镇滑坡灾害高和极高易发区占研究区总面积的25%，主要沿澧河分布；极高危险区和高危险区占研究区总面积的14%，主要分布在澧河北侧。 

Landslide hazard analysis of Liyuan Town based on effective rainfall threshold

This paper takes Liyuan Town of Hunan Province as an example, and used the weight of evidence model and the grey relational degree model to calculate separately the weights of the five factors of slope, formation lithology, shape of slope, land use type and human engineering activity in secondary states and in first states. After defining the landslide susceptibility index of the whole region by combining two models, the susceptibility zoning based on the slope unit is completed. According to the geotechnical geological type of the rock and soil in the study area (clastic rocks, carbonate nip clastic rocks, carbonate rocks and loose rock soils), the effective rainfall threshold curves (I-D curve) under different landslides occurrence probability are determined by grouping. The time probability of landslides in different rock and soil types under 3-day duration and effective intensity of 22.4mm/d is studied. Finally, the landslide hazard zoning map of Liyuan Town based on effective rainfall threshold is obtained through. combining time probability and susceptibility results. The results show that the high-susceptible areas and extremely high-susceptible areas account for 25% of the total study area and distributed mainly along the river. The extremely high-hazard areas account for 14% of the total study area and are mainly distributed in the north of the river.