基于数值模拟的强降雨诱发低频泥石流特征分析和危险性评价——以秦岭鸡窝子山洪泥石流为例  

Characteristics analysis and risk assessment of low-frequency debris flow induced by heavy rainfall based on numerical simulation——A case study of Jiwozi flash flood and debris flow in Qinling Mountains

作　　者：马志亮 庄建琦[1] 吴靓 曹琰波 陈生银 常磊 占洁伟 马鹏辉 孔嘉旭 Ma Zhiliang;Zhuang Jianqi;Wu Jing;Cao Yanbo;Chen Shengyin;Chang Lei;Zhan Jiewei;Ma Penghui;Kong Jiaxu(School of Geological Engineering and Geomatics,Changan University(Key Laboratory of Western Chinas Mineral Resources and Geological Engineering),Xian,Shaanxi 710054,China;Qinghai Institute of Geo-Environment Monitoring,Xining,Qinghai 810008,China)

机构地区：[1]长安大学地质工程与测绘学院(西部矿产资源与地质工程教育部重点实验室),陕西西安710054 [2]青海省地质环境监测总站,青海西宁810008

出　　处：《水土保持通报》2025年第1期147-157,177,共12页Bulletin of Soil and Water Conservation

基　　金：国家自然科学基金项目“重大滑坡预测预报基础研究”(42090053),“秦岭生态地质环境系统演化与灾害风险管控”(42341101),“工程地质与地质灾害”(41922054);科技部重点基础研究计划项目(2020YFC1512000)。

摘　　要：[目的]研究发育在秦岭山区的低频泥石流的特征及成因机制,为该地区此类低频泥石流的防灾减灾工作提供科学参考。[方法]以2023年“8·11”鸡窝子山洪泥石流为研究对象,通过野外调查、数值模拟等手段,采用实际降水频率,开展此次山洪泥石流形成过程反演,并进行危险性评价。[结果](1)强降雨快速汇集形成洪流,导致上游沟道松散物质被揭底侵蚀,形成“消防水管”效应,暴发山洪泥石流,并借助陡峭地形对全流域沟道进行侵蚀,大量堆积物和巨大冲击力在下游扩散开来形成堆积扇,并堵塞河道。(2)在实际降雨频率下模拟得出,泥石流全流域淤积深度在0.04~5.63 m,最大流速7.43 m/s,堆积扇面积1.91×10^(4) m^(2),一次性冲出量为78 271 m^(3)。(3)基于流速、泥深和危害范围,给出了高、中、低3个危险区域,堆积扇西侧区域地势较高,为低危险区,占堆积扇面积约10%,中间区域和堆积边缘至公路区域为中危险区,该类面积占62%,堆积扇东南和西南区域为高危险区,该类面积占28%。[结论] 2023年“8·11”鸡窝子山洪泥石流是一次典型由极端短时强降雨诱发的低频山洪泥石流灾害,FLO-2D模型可有效模拟泥石流的运动和沉积过程,并确定了泥石流的危险范围。[Objective]The characteristics and causal mechanisms of low-frequency debris flows in the Qinling Mountains was analyzed in order to provide a scientific reference for their prevention and mitigation.[Methods]The“8·11”Jiwozi flash flood and debris flow of 2023 served as the research subject.Using field investigations and numerical simulations,actual precipitation frequencies were used to reverse engineer the formation process of the flash flood and debris flow,and a risk assessment was carried out.[Results]①Intense rainfall accumulated quickly,forming torrents that erode loose materials in upstream channels.This process,known as the“fire hose”effect,triggered mountain floods and debris flows.Assisted by steep terrain,these flows eroded channels across the watershed,and a significant amount of sediment spreads downstream,forming alluvial fans and blocking river channels.②Simulations under actual rainfall frequencies showed that the sediment deposition depths across the watershed ranges from 0.04 to 5.63 meters,with a maximum flow velocity of 7.43 m/s.The area of the alluvial fan was 1.91×10^(4)m^(2),and the one-time discharge volume was 78271 m^(3).③Based on flow velocity,sediment depth,and hazard range,three danger zones were identified(high,medium,and low).The area on the western side of the alluvial fan,with higher elevation,was classified as a low-risk zone,accounting for approximately 10%of the fan area.The central area and the area from the edge of the fan to the road were classified as medium-risk zones,comprising 62% of the total area.The southeastern and southwestern areas of the alluvial fan were high-risk zones,accounting for 28% of the area.[Conclusion]The“8·11”Jiwozi flash flood and debris flow in 2023 was a typical low-frequency flash flood and debris flow disaster triggered by extreme short-duration heavy rainfall.The FLO-2D model effectively simulates the movement and deposition processes of the debris flow and determines the hazardous areas.

关 键 词：低频泥石流 数值模拟 危险性分区 秦岭鸡窝子山洪泥石流 

分 类 号：P642.23[天文地球—工程地质学]