北京延庆地区南湾道豁子沟泥石流发育特征

以北京市延庆地区南湾道豁子泥石流沟为研究对象,通过野外泥石流沟精细调查及历史资料统计,详细了解该泥石流发育特征和形成条件,针对流域内松散堆积物补给条件进行重点分析;综合研究该泥石流的动力学特征,进行泥石流危险区预测评价,提出相应的防治措施建议。研究结果表明:该泥石流沟内松散堆积物动储量为18.47×10⁴ m³,分为冲洪积、残坡积、人工堆积和崩滑塌等4种补给来源,其中冲洪积和残坡积所占比重最大;泥石流发展阶段处于衰退期;经动力学分析,洪峰流量值在10年一遇的降雨条件下为52.53 m³/s,20年一遇的降雨条件下为59.25 m³/s,50年一遇的降雨条件下为68.13 m³/s,100年一遇的降雨条件下为74.85 m³/s,对应的一次固体冲出总量分别为0.77×10⁴ m³、0.87×10⁴ m³、1.00×10⁴ m³和1.10×10⁴ m³;属于中型泥石流,最大危险区面积为0.238 3 km²。通过评价分析,该泥石流沟仍存在爆发中型泥石流的可能性,将对下游南湾村以及千沙公路行车和行人的生命财产安全造成威胁。研究成果可为延庆地区该类泥石流单沟预警模型研究和灾害防治提供科学依据。

Development Characteristics of Huozigou Debris Flow at Nanwandao,Yanqing District,Beijing

In this study, we investigated the Huozigou debris flow at Nanwandao(Yanqing district, Beijing). Through careful investigation and historical data statistics, the development characteristics and formation conditions of the debris flow are unraveled. Dynamic characteristics of the debris flow are studied comprehensively, and the risk area of debris flow are predicted and evaluated, and the corresponding prevention and control measures are proposed. The results show that the dynamic reserve of loose deposits in the debris-flow gully is 18.47×10⁴ m³, which contains four kinds of supply sources, including alluvial diluvial, residual deposit, artificial deposit, and landslide. The debris-flow development stage is in the decline phase. According to the dynamic analysis, the peak flow value is 52.53 m³/s for once-in-a-decade rainfall, 59.25 m³/s for once-in-a-decade rainfall, 68.13 m³/s for once-in-a-50-year rainfall, and 74.85 m³/s for once-in-a-century rainfall, with the total volume of one solid outfall being 0.77×10⁴ m³, 0.87×10⁴ m³, 1.00×10⁴ m³, and 1.10×10⁴ m³, respectively. It is a medium-sized debris flow, and the maximum danger area is 0.238,3 km². According to the evaluation and analysis, it is still possible to have medium debris flow in this gully, which poses a traffic safety threat to Nanwan village and Qiansha highway downstream. Our results provide a scientific basis for studying the mono-channel early-warning model of debris flow at Yanqing and the related disaster prevention and control.