沟谷空间特征与斜坡灾害发育关联性分析

Correlation aualysis on spatial characteristics of gully and slope disasters

沟谷作为一种侵蚀地貌,其空间特征对斜坡灾害发育有重要影响。以重庆市梁平县DEM数据为基础,应用Arc GIS软件的水文分析模块提取沟谷网络,以流域为划分标准得到7个研究区,分别采用分形理论和沟谷密度定量地研究沟谷空间特征。结合研究区内已发生289处斜坡灾害,从表征意义和相关系数两方面分析分维值和密度值与斜坡灾害发育的关联性,进而探讨沟谷两种特征值在斜坡灾害空间预测中的应用。研究表明,阈值为10时,提取沟谷网络与实际沟谷分布最为相符;研究区的沟谷形态分维值和密度均较小,并具有南北区域小、东西区域大的特点,符合实际调查中发现东西区域地表破碎程度强于南北区域的情况;在区域地貌处于幼年期时,相对于密度,分维值更能体现沟谷空间特征对斜坡灾害发育的影响,在斜坡灾害空间预测中有更高的实用价值。

Spatial characteristic of gully which is an erosion landform is the key to slope disasters. The DEM data of Liangping county in Chongqing is used to extract the gully network by the hydrologic analysis method. Spatial characteristic of gully of seven areas in watershed division are studied by the fractal theory and density quantitatively. Combined with the data of 289 slope disasters in Liangping,association of spatial characteristics of gully and slope disasters is analyzed by symbolical meanings and correlation coefficient. Then characteristic values of gully are used in slope disasters prediction. It was found that gully network agrees with the actual gully when the threshold value is 10. The fractal dimension value and density of gully are relatively small. Characteristic value of east and west region is greater than the other regional characteristic value according to the actual. Compared to density,the fractal dimension value of gully in juvenile period can reflect the relationship between spatial characteristic of gully and slope disasters,having higher practical value in the prediction of slope disasters.