基于面积?高程和面积?坡度积分的泥石流物质供给能力分析

松散物质是流域侵蚀演化的产物，对于泥石流流域而言，物质供给能力影响着泥石流的易发程度和活动频率。以岷江上游都江堰—汶川部分区域147个泥石流小流域为例，运用面积?高程法和面积?坡度积分对流域地貌演化阶段和侵蚀强度定量划分，并结合地貌演化阶段和侵蚀强度开展泥石流物质供给能力研究。研究结果表明:采用单一的地貌演化阶段或侵蚀强度解释泥石流的易发程度具有一定局限性，泥石流暴发主要集中于壮年期、壮年偏幼年期及侵蚀强度Ⅲ～Ⅴ级；随着物质供给能力的提升，泥石流的暴发率上升，而面积对泥石流的暴发有一定限制作用，初步确定研究区内供给能力处中、强、极强三种水平泥石流流域，其优势发育面积范围分别为:20～35 km2、10～50 km2、10～40 km2；对于物质供给能力水平较高、面积处于优势发育范围内、且长期未有明显泥石流活动迹象的流域，应进一步排查流域松散物质储量和分布特征，确定泥石流活动稳定性，采取合理的防灾减灾措施。

The material supply ability analysis of debris flows based on area-hypsometric integral and area-gradient integral

The loose material is produced by erosion and evolution of basins. The material supply ability affects the susceptibility degree and activity frequency of debris flow for debris flow basins. Taking 147 debris flow basins as a case, located in parts of Dujiangyan and Wenchuan, using the area-hypsometric integral and the area-gradient integral, the geomorphologic evolution stage and erosion intensity were quantified. Combined with the geomorphologic evolution stage and erosion intensity, the material supply ability analysis of debris flows was carried out. The results are as follows: it is not enough to explain the susceptibility degree only with the geomorphologic evolution stage or erosion intensity; the outbreaks of debris flow are mainly concentrating on the stage of maturity, maturity partial youth age and the erosion intensity Ⅲ—Ⅴ level; with the improvement of the material supply ability, the outbreak rate of debris flow increases, and the basin area plays a significant role in limiting the formation of debris flow; for medium, strong, and extremely strong supply ability levels, debris flow preponderant development area ranges are: 20—35, 10—50, 10—40 km2 respectively, in the study area; the investigation of material reserve and distribution should be carried out on the basin, which with a high level of material supply ability and in the optimal range of area and with unapparent debris flow activity for a long time, to confirm the stability of debris flow and formulate disaster control plans reasonably.