干热河谷冲沟沟头跌水消能减蚀措施效益试验初探  

The Benefit of Measures of Energy Dissipation and Erosion Reduction by Falling Water in Gully Head of Dry Hot Valley

作　　者：张宝军[1,2] 吴汉[1,2] 熊东红[1,2] 袁勇 ZHANG Baojun;WU Han;XIONG Donghong(Key Laboratory of Mountain Disasters and Surface Processes,Chinese Academy of Sciences,Chengdu,Sichuan 610041,China;Chengdu Institute of Mountain Disasters and Environment,Ministry of Water Resources/Chinese Academy of Sciences,Chengdu,Sichuan 610041,China)

机构地区：[1]中国科学院山地灾害与地表过程重点实验室,四川成都610041 [2]中国科学院水利部成都山地灾害与环境研究所,四川成都610041

出　　处：《中国水土保持》2020年第7期32-35,I0001,共5页Soil and Water Conservation in China

基　　金：中国科学院“西部之光”人才培养引进计划“西部青年学者”项目(2019年度入选);国家自然科学基金项目(41571277);国家重点研发计划课题(2017YFC0505102)。

摘　　要：沟头是金沙江下游干热河谷区冲沟发育最为活跃的部位,具有“跌坎陡立、地形落差大、跌水能量大、径流冲刷剧烈”等特征。研究如何有效消减沟头跌水能量、减少侵蚀产沙,是干热河谷区开展活跃沟头治理的关键。通过多种处理下的消能试验,发现消能池设计可以有效消减沟头跌水能量,消能率在92%以上,其大小与跌水高度、放水流量、填充材料和消能池深度等有关。消能率随跌水高度、放水流量和消能池深度增大呈增大趋势,软质的扭黄茅材料较鹅卵石填充消能效果更佳。沟头跌水在下落过程中与下垫面发生剧烈碰撞、摩擦,会耗散极大能量,在沟头跌坎底部设置消能池,可以避免跌水耗散能量直接作用于土体,减缓沟头溯源侵蚀过程的发展。与无填充相比,消能材料填充可使跌水侵蚀产沙减少49.6%~89.2%,平均减少74.2%。Gully head is the most active part of gully development in dry-hot valley area of the lower reaches of Jinsha River,having the characteristics of“steep falling-sill,large terrain drop,large drop energy and severe runoff erosion”.How to effectively reduce the energy of gully head drop and reduce erosion and sediment yield is the key of active gully head control in dry-hot valley.Through energy dissipation test under various treatments,it is found out that the design of plunge pool can effectively reduce the energy of water drop energy of gully head,energy dissipation rate is over 92%and its size is related to the height of water drop,discharge flow,filling material and depth of plunge pool.The energy dissipation rate increases with the increase of drop height,discharge and depth of plunge pool and the energy dissipation effect of soft Heteropogon contortus material is better than that of cobblestone.In the process of falling water at the head of gulley,it will cause violent collision and friction with the underlying surface and dissipate a lot of energy.To build a plunge pool at the bottom of gully head falling-sill can avoid the direct effect of water drop dissipation energy on soil and slow down the development of erosion process of the head of gulley.Comparing with no filling,the filling of energy dissipation material can reduce the erosion and sediment yield by 49.6%to 89.2%and the average reduction is 74.2%.

关 键 词：跌水高度 消能池 消能率 沟头 干热河谷 

分 类 号：S157.1[农业科学—土壤学]