地形坡度对鄂渝地区水库型堆积层滑坡贡献率研究

摘要

Debris landslide is one of the most common types of landslides in reservoir region.Slope gradient is an important internal cause of the development of landslides.The relation between slope gradient and probability of occurrence of debris landslide in reservoir region has important significance to debris landslide risk assessment in reservoir region.This paper takes 1 39 debris landslides in the Three Gorges Reservoir region and Danjiangkou Reservoir region as example.Firstly,it divides the slope gradient into 7 intervals.Each adjoining 5°is an interval. Based on above,the influence that slope gradient contributes to landslide growth is quantitatively analyzed by contribution rate method.The results show that,the slope gradients of 1 5°~25°have the maximum contribution rate.The slope gradients of 1 0°~1 5°and 25°~30°have the intermediate contribution rate.The slope gradients greater than 30°and less than 1 0°have the minimal contribution rate.The results can provide potential gist to risk evaluation for debris landslide in reservoir region.%堆积层滑坡是库区常见的滑坡类型之一，而地形坡度是滑坡发育的重要内因，研究地形坡度与堆积层滑坡发生概率之间的关系对水库型堆积层滑坡的危险性评价具有重要意义。以三峡库区及丹江口库区的139处堆积层滑坡为例，首先，将滑坡地形坡度以每隔5°划分为一个区间，总共分为7个区间；在此基础上，采用贡献率方法，定量研究了地形坡度分别对滑坡数量、面积、体积的贡献率；最后，通过迭加统计，得到了不同坡度区间对滑坡发生的综合贡献率。结果表明，15°～25°的地形坡度对水库型堆积层滑坡的贡献率最高，10°～15°及25°～30°的地形坡度对水库型堆积层滑坡的贡献率中等，小于10°及大于30°的地形坡度对水库型堆积层滑坡的贡献率最小。研究结果可为具有类似地质背景的水库型堆积层滑坡危险性评估及防治规划提供参考依据。