基于物源特征的白龙江流域泥石流易发性评价

白龙江流域是泥石流地质灾害的易发区和高发区,历史上曾发生过多次泥石流灾害。为探讨物源对泥石流的影响,对流域内泥石流物源数量、类型、分布进行了详细地调查分析,进而研究了物源转化泥石流的方式。在分析泥石流物源发育影响因素的基础上,采用确定性模型与灰色关联组合方法,筛选出物源敏感性、坡面侵蚀程度、沟床比降、沟壑密度四个因子,运用AHP模型进行区域泥石流易发性区划。得出以下认识：(1)白龙江流域泥石流物源分为重力侵蚀堆积型、坡面侵蚀汇集型、沟道侵蚀堆积型和弃渣侵蚀堆积型。其中物源量最多的为重力侵蚀堆积型,分布面积最广的是坡面侵蚀汇集型；(2)泥石流的物源多分布于坡度在15°~45°范围内的斜坡上,1 000~2 500 m的高程范围内,距离断裂500 m范围内,且物源量与植被覆盖率呈较好的负相关性；(3)流域内物源转化为泥石流的方式主要有崩落冲刷拉槽型、集中堵塞溃决型、沟道揭底铲刮型、坡面径流侵蚀溜滑型；(4)白龙江流域泥石流高易发区位于物源分布密集区,即泥石流流域中下游两岸。

Evaluation of Debris Flow Susceptibility in Bailong River Basin Based on Source Characteristics

The Bailong River Basin is a prone and high-incidence area for debris flow geological disasters. There have been many mudslides in history. In order to investigate the influence of provenance on debris flow, the quantity, type and distribution of debris flow sources in the basin were investigated and analyzed in detail, and then the way of turning debris flow into the source was studied. Based on the analysis of the factors affecting the development of debris flow source, the deterministic model and the grey correlation method are used to screen out the four factors of source sensitivity, slope erosion degree, ditch bed ratio drop and gully density. The AHP model was used to carry out regional karst flow susceptibility zoning. The following understandings are drawn: (1) The debris flow source in the Bailong River Basin is divided into gravity erosion accumulation type, slope erosion collection type, channel erosion accumulation type and waste slag erosion accumulation type. Among them, the most abundant source is the gravity erosion accumulation type, and the most widely distributed area is the slope erosion collection type; (2) The source of the debris flow is mostly distributed on the slope with the slope in the range of 15°~45°, In the elevation range of 1 000~ 2 500 m, the distance from the fault is 500 m, and the source quantity has a good negative correlation with the vegetation coverage rate. (3) The way of converting the provenance into debris flow in the basin mainly includes caving and scouring type. (4) The high-prone area of the debris flow in the Bailong River Basin is located in the densely distributed area of the source, that is, the two sides of the debris flow.