滇东北滑坡孕灾环境因子敏感性分析

Sensitivity analysis on environmental factors for landslides in Northeastern Yunnan

以云南省滑坡地质灾害严重的滇东北作为研究区,在建立滇东北滑坡地质灾害数据库的基础上,依托ArcGIS软件和确定性系数分析方法,对高程、坡度、坡向、降雨量、岩石硬度、距道路距离、距河流距离、距断裂距离8个孕灾环境因子进行敏感性分析,以进一步梳理滇东北地区滑坡发育的环境特征。研究发现:①坡度、距道路距离、高程对研究区内的滑坡的空间分布具有较强控制作用。在35°~40°的坡度范围内滑坡发生的确定性高,CF值为0.4666;在距道路距离0~400 m范围内滑坡发生的确定性高,CF值为0.3544;在1200~1600 m高程范围内滑坡发生的确定性高,CF值为0.3156。②在135°~180°坡向范围内滑坡发生的确定性较高,CF值为0.2949,且该坡向多为阳坡,居民点及人类活动较多。③岩石硬度、降雨量、距河流距离、距断裂距离的CF值均较小,显示研究区滑坡发生对这4个孕灾因子敏感性较低,相关性不明显。通过对各孕灾环境因子的敏感性分析,可为滇东北进一步建立滑坡地质灾害预警模型提供帮助。

In this paper,taking the northeast area of Yunnan Province as the research area,based on establishing a database of landslide geological hazards in Northeastern Yunnan Province,relying on ArcGIS software and deterministic coefficient analysis method,a sensitivity analysis of eight environmental factors including elevation,slope,aspect,rainfall,rock hardness,distance from road,distance from river and distance from fault were carried out,so as to further comb the environmental characteristics of landslide development in Northeast Yunnan.The results showed that:(1)slope,distance from road and elevation had strong control effect on the spatial distribution of landslides in the study area.In the range of 35°~40°slope,the CF value was 0.4666;in the range of 0~400m away from the road,the CF value was 0.3544;in the elevation of 1200~1600 m,the CF value was 0.3156;the certainty of landslide occurrence in the above situations werere high.(2)In the range of 135°~180°slope direction,CF value was 0.2949,the certainty of landslide occurrence was high,where the slope was mostly sunny and affected more by human activities.(3)The CF values of rock hardness,rainfall,distance from river and distance from fault were small,showing a low sensitivity of landslide occurrence to these four disaster pregnant factors,and the correlation was not obvious.Through the sensitivity analysis of the environmental factors,it can provide help for the establishment of landslide geological hazard early warning model in Northeastern Yunnan.