强震区沟谷宽缓组合对泥石流动力学特征影响研究  

Influence of combination of gentle and steep gullies on dynamic characteristics of debris flows in a strong earthquake area

作　　者：赵宇鹏 杨太强 王昆 程伟 罗军尧 ZHAO Yupeng;YANG Taiqiang;WANG Kun;CHENG Wei;LUO Junyao(Faculty of Land and Resources Engineering,Kunming University of Science and Technology,Kunming 650093,China;Power China Kunming Survey and Design Institute,Kunming 650051,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]中国电建集团昆明勘测设计研究院有限公司,云南昆明650051

出　　处：《人民长江》2024年第6期167-175,共9页Yangtze River

基　　金：国家自然科学基金联合基金项目(U22A202602)。

摘　　要：岷江上游分布着大量宽缓型和窄陡型泥石流沟,沟道的宽缓和窄陡对泥石流动力学特征具有重要影响。以岷江上游宽缓型沟谷桃关沟为研究对象,采用Massflow软件模拟再现了沟谷内泥石流的动力过程,得到了“宽缓支沟+宽缓主沟”“窄陡支沟+宽缓主沟”两种组合下的泥石流动力学特征。研究表明:流域内不同级别支沟间的宽缓组合对泥石流的运移具有显著影响,这种沟间组合因素影响了泥石流的速度和泥深。“窄陡+宽缓”组合下,前期泥石流流速较大,下蚀效应明显,扩散路径长,后期多淤积;而“宽缓+宽缓”组合下,沟内泥石流的侧蚀效应更显著,加剧了沟道的演化。这两种组合下的泥石流均有堵塞河道进而发育成堰塞湖的风险。研究成果提高了关于沟道宽缓组合对泥石流运移影响的认识,可为沟谷类泥石流危险性评价提供参考。There are a large quantity of wide-gentle gullies and narrow-steep gullies in upstream of Minjiang River basin.The geometry of gullies has important influences on kinetic characteristics of debris flows.Taking Taoguangou gully,a wide-gentle gully in the upper reaches of Minjiang River,as the research object,we used Massflow software to simulate the dynamic process of debris flow in the gully,and the dynamic characteristics of debris flow with"narrow-steep branch channel+wide-gentle main channel,or wide-gentle branch channel+wide-gentle main channel"were obtained.The results show that the combination of wide-gentle channels of different levels in the basin has a significant effect on the initiation mode and behavior of debris flows,which affects the velocity and mud depth of debris flows.Under the combination of"narrow-steep+wide-gentle",the flow velocity of debris flow is large in the early stage,the effect of down-cutting is obvious,the run-out path is long,and the sedimentation is more in the later stage.Under the combination of"wide-gentle+wide-gentle",the lateral erosion effect of debris flow in the trench is more significant,which intensifies the evolution of the trench.Both the two combinations have the risk of blocking the river and developing into a barrier lake.This study improves the understanding of the influence of wide-gentle channel combination on debris flow migration and is helpful to the future risk assessment of debris flow.

关 键 词：泥石流 沟谷形态 宽缓-窄陡 动力特征 强震区 岷江上游 

分 类 号：P642.23[天文地球—工程地质学]