龙川县米贝村1#泥石流灾害特征与运动过程

受区域气流影响,广东省龙川县在2019年6月10~13日出现持续强降雨天气,累计降雨量超过260mm,从而引起全县发生大量滑坡、泥石流灾害。本文以米贝村1#泥石流为研究对象,在野外调查认识基础上,结合Fluent数值分析对这类低山丘陵区的小型泥石流灾害运动特征展开研究。研究发现:米贝村1#泥石流受沟床粗糙度、纵坡降、流向等因素影响,其流速具有动态变化特征,总体表现为先增大再减小的发展趋势,泥石流物质的变化对其运动速度有一定影响。在整个过程中最大流速可达9.77m/s,平均速度为3.31m/s,与实际调查结果相符。研究成果不仅可直接为米贝村重在区灾后工程防治提供指导,对于东南沿海相似地区的降雨型滑坡-泥石流灾害的研究具有借鉴作用。

Study on 1# debris flow disaster characteristics and movement process in Mibei village, Longchuan County

Longchuan County, situated in Guangdong Province, was subjected to persistent heavy rainfall from June 10 to 13, 2019. The aggregate precipitation during this interval surpassed 260 mm, resulting in a multitude of landslides and debris flows within the county. This study focuses on the debris flow labeled as 1# in Mibei village. Employing field investigations and comprehensive comprehension, coupled with meticulous numerical analysis, the research investigates the movement traits of minor debris flows within areas marked by low mountainous and hilly topographies. The investigation reveals that the gully connected with the 1# debris flow in Mibei village displays noteworthy attributes, characterized by a compact length, significant longitudinal gradient, and intricate topographic variations. Variables such as the roughness of the gully bed, longitudinal gradient, and flow direction influence the velocity of the debris flow, giving rise to dynamic fluctuations. Typically, the velocity displays an initial increment followed by a subsequent decrement. Alterations in debris composition also exert an influence on its velocity. Over the entire course, the maximum velocity reaches 9.77 m/s, whereas the mean velocity rests at 3.31 m/s. These values are consistent with findings from empirical investigations. The results of this study not only provide immediate guidance for post-disaster engineering preparedness and mitigation efforts in Mibei village but also serve as a point of reference for exploring disasters arising from rainfall-induced landslides and debris flows in comparable areas along the southeastern coast.