基于HI值的河流裂点与谷坡稳定性关系

Relationship Between Knickpoint and Stability of Valley Slope Based on Hypsometric Integral Value

为定量分析河流裂点对流域地质灾害分布的影响,基于面积-高程积分(HI)方法,利用ArcGIS和MatLab软件,首先计算了喜马拉雅山中部以及青衣江流域的HI值与崩塌滑坡密度之间的相关关系;然后以喜马拉雅山地区的雅鲁藏布江、印度河、波曲(Bhote Koshi河)、马甲藏布、朋曲(Arun河)和Kali Gandaki共6条河流为对象,分析不同河流裂点的成因;最后计算了所有河流裂点上、下游流域的HI值。所得结论如下:①流域HI值与崩塌滑坡密度存在良好的正相关关系,相关系数均>0.5;②河流裂点上游流域的HI值均小于下游,说明上游流域的整体稳定性强于下游;③构造成因的河流裂点上、下游流域HI值差别较大(最小为0.06),而堵河成因的河流裂点上、下游流域HI值差别较小(最大为0.02)。研究成果为宏观定量判定山区谷坡稳定性提供了参考。

The influence of river knickpoint on the distribution of geological hazards in river basin was analyzed quantitatively using the hypsometric integral(HI)method.First of all,the correlation between HI values and landslide density in the central Himalayas and the Qingyi River basin was calculated using ArcGIS and MatLab software;subsequently the causes of knickpoints of the Yarlung Zangbo River,the Indus River,the Boqu River,Majiazangbo River,the Pengqu-Arun River and the Kali-Gandaki River in the Himalayas region were analyzed;finally the HI values of watersheds within the knickpoints’upstream and downstream areas of all the rivers were calculated.The results are concluded as follows:(1)the HI value is in a good positive correlation with landslide density,with all correlation coefficients greater than 0.5;(2)the HI value in the upstream basin of knickpoint is smaller than that in the downstream basin,indicating that the overall stability of upstream river basin is stronger than that of downstream;(3)for knickpoint of tectonic origin,the HI values of downstream and upstream river basins are quite different(the minimum is 0.06),while for knickpoint of river blocking origin,the difference of HI values between upstream and downstream is small(the maximum is 0.02).The results provide a reference for macroscopically and quantitatively determining the stability of valley slope.