长江中下游岸坡单元体的水力侵蚀室内试验研究  

Hydraulic erosion tests on river bank slope units in middle and lower reaches of Yangtze River

作　　者：李瑞祥 周成[1] 李旭[1] 何宁[2] 钟启明[2] 张桂荣[2] LI Ruixiang;ZHOU Cheng;LI Xu;HE Ning;ZHONG Qiming;ZHANG Guirong(College of Water Resource&Hydropower,State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065,China;Geotechnical Engineering Department,Nanjing Hydraulic Research Institute,Nanjing 210024,China)

机构地区：[1]四川大学山区河流保护与治理全国重点试验室,四川大学水利水电学院,四川成都610065 [2]南京水利科学研究院岩土工程研究所,江苏南京210024

出　　处：《岩土工程学报》2024年第S01期53-58,共6页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金联合基金重点项目(U2340227,U22A20602)。

摘　　要：水作用下长江中下游岸坡正在面临严峻的崩岸破坏。为探究岸坡土体的水力侵蚀特性,进行单元体单面浸水湿化-崩解试验与侧向冲刷水毁室内试验,通过分析冲刷沟形态、测量单元体质量、探究侧向冲刷深度和高度变化规律,研究根系和格栅植被面层对单元体侵蚀破坏的影响,分析运用乔木根系联合格栅植被面层对岸坡进行防冲的可行性。试验结果表明:湿化-崩解与侧向冲刷二者共同作用,引起和加剧岸坡土体的淘蚀破坏。随着水深、流速及冲刷时间的增加,单元体侧向冲刷深度与冲刷高度一直增加;在本实验较小的单元体尺寸下,较粗的乔木模拟根系对于减小单元体冲蚀破坏程度的作用有限,其根土间隙优先流效应在一定程度上反而增加侧向冲刷深度;根系对黏性土的牵拉锚固作用明显强于粉土质砂,能够延缓上部土体的崩塌;设置格栅植被面层后,可有效减小单元体侧向冲刷深度,抗冲效果显著,研究结果可为生态护岸技术研发和应用提供借鉴。The river banks in the middle and lower reaches of the Yangtze River are facing severe hydraulic erosion.To explore the hydraulic erosion characteristics of bank slope soils,the single face soaking-immersion erosion tests and lateral erosion tests by flowing are conducted.By analyzing the morphology of erosion gullies,measuring the mass of single units,investigating the lateral depth and height loss by flowing erosion and studying the influences of roots and grid-vegetation layers on the erosion and destruction of soil units,the feasibility of using tree roots combined with grid-vegetation layers to prevent erosion on the bank slopes is studied.The test results show that both wetting erosion and flowing erosion jointly cause the erosion and destruction of bank slope soils.With the increase of the water depth,flow velocity and erosion time,the lateral depth and height of the lost unit by flowing erosion continuously increase.Under the small unit size of the tests,the effects of simulating roots with coarse tree roots on reducing the erosion and destruction of units are limited.The preferential flow effects of root-soil gaps actually increase the lateral erosion depth to some extent.The anchoring effects of roots on cohesive soil are significantly stronger than those on sandy loam,which can delay the collapse of the upper soil.After setting up the grid-vegetation layer,the lateral erosion depth of the unit can be effectively reduced,and the erosion resistance effects are significant.The research results can provide reference for ecological bank protection.

关 键 词：长江中下游河岸 根土复合体 格栅植被面层 湿化-崩解-侧向冲刷 单元体试验 

分 类 号：TV871[水利工程—水利水电工程] TV861