白龙江流域潜在泥石流堵江-溃决洪水链式灾害演进过程  

Potential chain disaster evolution process of debris flow blockage and dam failure floods in the Bailong River basin

作　　者：李宏杰 常鸣[1] 唐亮亮 王高峰[2] 李林泽 夏喆 朱习松 倪章 LI Hongjie;CHANG Ming;TANG Liangliang;WANG Gaofneg;LI Linze;XIA Zhe;ZHU Xisong;NI Zhang(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China;Center for Hydrogeology and Environmental Geology of CGS,Baoding Hebei 071051,China)

机构地区：[1]成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610059 [2]中国地质调查局水文地质环境地质调查中心,河北保定071051

出　　处：《地质科技通报》2024年第6期196-211,共16页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金面上项目(42077245);四川省自然科学基金项目(2024NSFSC0071);四川甘孜州道孚抽水蓄能电站下水库泥石发育特征及其对工程的影响项目(AH2023-0490);四川省中央引导地方科技发展专项项目(自由探索类基础研究)(2024ZYD0121)。

摘　　要：受“5·12”汶川大地震影响,白龙江流域由泥石流引发的堵江-溃决洪水链式灾害出现的频率显著增加。同时,由于特殊的地质环境条件,白龙江流域很多城镇都位于峡谷阶地、泥石流堆积扇等地区,极易受到泥石流堵江-溃决洪水链式灾害的威胁。为探究白龙江流域潜在泥石流堵江-溃决洪水链式灾害的危险性,以甘肃省舟曲县白龙江流域的寨子沟泥石流为研究对象,旨在正确认识寨子沟泥石流堵江-溃决洪水链式灾害的孕灾特征、致灾条件及演化模式,明确泥石流引发的链式灾害威胁范围。通过遥感解译与野外调查等方法,构建寨子沟泥石流地形地貌和物源数据库,核算了该泥石流静动力学参数,并在此基础上分析了泥石流堵河和溃决洪水的灾害链效应。选用FLO-2D和HEC-RAS模型,开展了不同降雨频率下(P=1%,2%)的泥石流演进数值仿真,获取了泥石流和溃决洪水的深度、流速和威胁范围等特征参数,并基于特征参数分析了泥石流和溃决洪水危害强度并评估潜在危险。结果表明:(1)百年一遇降雨频率下的寨子沟泥石流流动最大流速可达11.96 m/s,泥石流冲出物进入河道形成的堰塞坝平均厚度约10 m,造成白龙江完全堵塞,堰塞湖库容为6.26 km^(3)。(2)溃决洪水演进过程总时长约为12 h,溃口流量达到顶峰时间约30 min,其溃决影响范围为沿白龙江主干流甘南州舟曲县峰迭镇下游至陇南市武都区桔柑乡上游段河谷及两岸区域,面积达56.36 km^(2),距离约97.4 km。结合模拟结果,初步探讨了监测与治理为一体的流域性泥石流灾害链风险防控模式。该研究强调了传统模型在洪水灾害评估中的局限性,并有助于深入了解泥石流堵江引起的洪水灾害的连锁危害。研究成果可为白龙江中下游流域此类泥石流链式灾害风险评价和防治工程设计提供参考。[Objective]In the aftermath of the"5.12"Wenchuan earthquake,the frequency of chain disasters,precipitated by debris flow blockages and subsequent breaching floods,significantly increased in the Bailong River basin.The region′s distinctive geological conditions,characterized by numerous towns situated on canyon terraces and debris flow accumulation fans,further exacerbate its susceptibility to such chain disasters.This study aims to investigate the potential risks associated with debris flow blockages and flood chain disasters in the Bailong River basin,with a specific focus on the Zhaizi gully debris flow in Bailong River basin,Zhouqu County,Gansu Prov-ince.The objective is to elucidate the disaster-breeding characteristics,disaster-inducing conditions,and evolution patterns of the Zhaizi gully debris flow chain disaster,while also delineating the threat range posed by these chain disasters.[Methods]Through remote sensing interpretation and field surveys,a comprehensive database encom-passing the topography,geomorphology,and material sources of the Zhaizi gully debris flow was established.This facilitated the identification of the development characteristics and various physical and mechanical parameters of the debris flow.Using the FLO-2D and HEC-RAS models,numerical simulations were performed under different rainfall frequencies(P=1%,2%),yielding key parameters such as depth,flow velocity,and the threat range of the debris flow and breaching floods.These parameters facilitated the analysis of hazard intensity and potential risks associated with debris flows and breaching floods.[Results]Under a 100-year rainfall frequency,the maximum flow velocity of the Zhaizi gully debris flow can reach 11.96 m/s.The average thickness of the debris dam formed is approximately 10 m,leading to complete blockage of the Bailong River and the formation of a dammed lake with a capacity of 6.26 km^(3).The evolution of the breaching flood lasts approximately 12 hours,with the peak flow oc-curring about 30 minutes after breach.The i

关 键 词：泥石流 堰塞湖 河道堵塞 灾害链 演化过程 白龙江流域 寨子沟 甘肃舟曲 

分 类 号：P642.23[天文地球—工程地质学]