甘肃河西地区泥石流沟分布特征与易发性评估研究

Research on Distribution Feature of Debris Flow Gullies and Their Susceptibility Evaluation in Hexi Area of Gansu Province

根据汇水面积、松散物质储量、沟坡坡度、主沟纵坡降等4项泥石流沟易发性判断特征指标,利用数理统计方法,对甘肃省河西地区20个县、区、市的587条泥石流沟现状进行了分析研究.结果表明:河西地区泥石流多发育在南北山地的前山走廊地带,泥石流沟分布密度稀疏,属于泥石流稀疏地区.在泥石流沟易发性主要特征指标方面,研究区汇水面积指标处于偏轻微程度,松散物质储量指标处于中等程度,沟坡坡度指标处于严重程度,主沟纵坡降指标处于中等以下程度.在泥石流沟易发性评价结果方面区域总体属于泥石流地质灾害低易发-中易发区域.在全球气候变暖的背景下,研究区内强降水情况发生频率呈现增强趋势,应积极开展极端天气影响下河西地区泥石流发展趋势和干旱、半干旱地区植被特征与泥石流易发性之间的相关关系研究.

There are 587debris flow gullies have been investigated in 20counties,districts and cities in Hexi Corridor area in Gansu Province by debris flow gully judgment standards,four characteristics of catchment area,loose material reserves,slope gradient and main gully longitudinal slope,taken as the measure indexes.The statistics from the field work and information analyses have shown that debris flow gullies in Hexi area mainly developed in the corridor of the fore range of southern and northern hilly areas,and they have a sparse distribution density and belong to sparse debris flow areas;geological disasters caused by debris flow in this area on the whole have a low and middle-level tendency of occurrence based on the results of susceptibility evaluation of debris flow gullies.The results also indicate that heavy rain occurring frequency in the research area showed a trend of increase under the influences of global warming.Therefore,it is suggested that studies be actively carried out on the debris flow development trend in Hexi area and on the correlativity between vegetation and occurrence susceptibility of debris flow in arid and semi-arid areas.