四川汶川县板子沟“6·26”特大型泥石流成因特征与活动性研究  

Characteristics and activity analysis of the catastrophic“6·26”debris flow in the Banzi catchment,Wenchuan County of Sichuan Province

作　　者：张宪政 铁永波 宁志杰 杨昶 李宗亮 李明辉 梁京涛[5] 卢佳燕 鲁拓 李光辉 李果 向炳霖 ZHANG Xianzheng;TIE Yongbo;NING Zhijie;YANG Chang;LI Zongliang;LI Minghui;LIANG Jingtao;LU Jiayan;LU Tuo;LI Guanghui;LI Guo;XIANG Binglin(Chengdu Center of China Geological Survey(Geosciences Innovation Center of Southwest China),Chengdu,Sichuan 610081,China;Technology Innovation Center for Risk Prevention and Mitigation of Geohazard,Ministry of Natural Resources,Chengdu,Sichuan 611734,China;Observation and Research Station of Chengdu Geological Hazards,Ministry of Natural Resources,Chengdu,Sichuan 610000,China;Chinese Academy of Geological Sciences,Beijing 100037,China;Sichuan Geological Survey,Chengdu,Sichuan 610084,China)

机构地区：[1]中国地质调查局成都地质调查中心(西南地质科技创新中心),四川成都610081 [2]自然资源部地质灾害风险防控工程技术创新中心,四川成都611734 [3]自然资源部成都地质灾害野外科学观测研究站,四川成都610000 [4]中国地质科学院,北京100037 [5]四川省地质调查院,四川成都610084

出　　处：《水文地质工程地质》2023年第5期134-145,共12页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金项目(U20A20110-01);中国地质调查局地质调查项目(DD20221746)。

摘　　要：2023年6月26日,四川省阿坝州汶川县板子沟发生灾害性泥石流,沟口冲出总量约8.28×10^(5) m^(3),堵塞岷江并形成面积约0.4 km^(2)的堰塞湖。为揭示汶川震后15 a仍发生特大型泥石流事件的内在成因机制,采用现场调查、遥感解译、地形叠加分析与动力学参数计算等方法,分析板子沟泥石流的成因和堵江特征,并在此基础上提出防治建议。研究结果表明:(1)板子沟泥石流触发降雨具有短历时高强度的特征,泥石流以沟道物源启动为主;(2)泥石流洪峰流量高达755.5 m^(3)/s,是导致堵塞岷江的主要原因;(3)板子沟泥石流表明,震后这类泥石流的活动性因物源耦合输移而具有滞后性和长期性特点。建议加强震区泥石流隐蔽型同震滑坡物源和沟道物源动态调查评估。研究结果有助于深化对震后泥石流活动性演变规律的认识,并可为震后泥石流的防治提供科学参考。On 26 June 2023,a catastrophic debris flow occurred in the Banzi Catchment in Wenchuan county of Sichuan province.This debris flow event is a viscous debris flow triggered by short duration heavy rainfall.The volume of debris which transported out of the catchment by debris flow is more than 8.3×10^(5) m^(3),and the debris flow blocked the Minjiang River.The river blockage formed a barrier lake with an area of about 0.4 km^(2).To reveal the formation mechanism of the occurrence of the extremely large debris flow events 15 years after the Wenchuan earthquake,This paper adopts a comprehensive method of field investigation,image interpretation,topographic superposition and calculation of forced vortex.This paper also analyzes the formation mechanism of debris flow and the characteristics of river blocking.Based on the results,this paper gives some suggestions of investigation and prevention of debris flow in the Banzi catchment.The research results show that(1)the triggering rainfall is characterized by short duration and high intensity.The main initiation positions are in the channel.The main debris supply is from the debris deposition along the channel.(2)The peak discharge of debris flow is as high as 755.5 m^(3)/s,which is the main cause of river blockage.(3)Since the Wenchuan earthquake,the debris flow activity of the Banzi Catchment has the characteristics of lag and long-term because of the coupled transport of debris on the slope and along the channel.(4)The volume of the debris source which can be eroded along the channel should be paid more attention in subsequent investigation and prevention.The research results are helpful in better understanding of the activity evolution of the post-seismic debris flow.They can also provide scientific references for the prevention of the post-seismic debris flow.

关 键 词：汶川县 板子沟 震后 泥石流 岷江 堵江 

分 类 号：P642.23[天文地球—工程地质学]