八角楼乡火后泥石流空间发育特征

作为一种与林火密切相关的特殊泥石流,火后泥石流的形成具有明显的空间差异性,对其空间发育特征及影响因素的分析有利于此类泥石流的防灾减灾.?运用现场调查、室内外试验和遥感解译等手段,对雅江县八角楼乡火烧迹地15条沟道的火后泥石流发育特征及地形、林火、植被特征、降雨条件进行了多元分析.?结果表明:火烈度越强,土壤的物理力学性...

Spatial Development Characteristics of Post-Fire Debris Flow in Bajiaolou Town

As a special type of debris flows closely relevant to forest fire, the generation of post-fire debris flow often shows a spatial variation. It is of great significance to analyze the spatial development characteristics and its influencing factors for hazard mitigation and reduction. By means of field investigation, in-situ and laboratory tests, and remote sensing interpretation, multi-factor analysis was conducted on the 15 channels in the burned area in Bajiaolou town of Yajiang county in terms of their spatial development characteristics, topography, forest fire, vegetation and rainfall conditions. The results show that the higher the fire intensity, the stronger the soil water repellency and the lower the permeability; moreover, the physical and mechanical properties of soil deteriorate more seriously, which contribute to the generation of post-fire debris flow. The occurrence frequency of post-fire debris flow rises when the burned area become larger and the vegetation cover coefficient lower. In contrast to the large basins, the smaller basins show more vulnerability to post-fire debris flow for their short channel lengths and high longitudinal slopes. Besides, the recurrence time of the triggering rainfall intensity that corresponds to four of five debris-flow events in the study areas is less than 5 years, and the triggering rainfall intensity also increases with time.