摘要
兰新高速铁路横穿多个大风区,对其安全运营造成严重影响。为降低强风对线路的危害,在大风区修筑大量防风构筑物,其中以路基挡风墙最为常见,挡风墙降低了风害的影响,但是带来严重的线路积沙问题。通过数值模拟研究不同风速下路基双侧挡风墙周围的流场特征,利用风产生的壁面剪切应力与沙粒剪切应力的比值确定地表沙粒沉积与侵蚀类型。研究发现,气流在两道挡风墙之间分别形成一个顺时针涡流和一个逆时针涡流,在第二道挡风墙背风侧形成一个顺时针大涡,随着来流风速增大,漩涡尺寸和涡流强度均在增大;由于涡流的存在,部分沙粒被卷走,路堤背风坡附近以及路基面上的沙粒沉积显著减少,当来流风速为24、30 m/s时,南北侧线路道床面均出现沙粒反向侵蚀;单双侧挡风墙的积沙规律对比结果表明,设置双侧挡风墙时,线路积沙显著减少。研究揭示了大风区铁路双侧挡风墙周围路基面上的沙粒沉积规律,对未来风区铁路的防护建设具有指导意义。
The Lanzhou—Xinjiang high-speed railway traverses multiple strong wind areas,causing a serious impact on its safe operation.In order to reduce the harm of strong winds to the railway line,a large number of windproof structures have been built in the strong wind areas,with subgrade windbreak walls the most common.Despite the reduction of the impact of wind damage,windbreak walls cause serious line sand accumulation problems.In this paper,the characteristics of the flow field around the windbreak walls on both sides of the subgrade under different wind speeds were studied through numerical simulation.The ratio of wall shear stress generated by wind to sand shear stress was used to determine the type of surface sand deposition and erosion.It is found that a clockwise vortex and a counterclockwise vortex are formed between the two rows of wind barriers,with a clockwise large vortex formed on the leeward side of the second row of wind barriers.With the increase of incoming wind speed,the size and intensity of the vortex both increasing.The existence of eddy current sweeping away some sand particles significantly reduces the sediment of sand particles near the leeward slope of the embankment and on the subgrade surface.When the incoming wind speed is 24 m/s and 30 m/s,reverse erosion of sand particles appears on the subgrade surface of up and down tracks.The results of the comparison of sand accumulation laws between single and bilateral wind barriers show that the installation of bilateral wind barriers significantly reduces the sand accumulation on the line.This study not only reveals the law of aeolian sand deposition on the subgrade surface around the bilateral windbreak walls of the railway in the windy area,but also has important guiding significance for the protection construction of the railway in the windy area in the future.
作者
张凯
赵礼明
王正辉
邓育辉
谭立海
ZHANG Kai;ZHAO Liming;WANG Zhenghui;DENG Yuhui;TAN Lihai(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of Desert and Desertification,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2024年第6期148-155,共8页
Journal of the China Railway Society
基金
中国博士后科学基金(2021M703466)
甘肃省科技计划(20JR10RA231)
2023年甘肃省教育科技创新项目(2023A-045)
干旱半干旱地区光伏电站对生态环境的影响机制及生态恢复技术研究及应用(HNKJ21-H76)。
关键词
大风区
高速铁路路基
挡风墙
数值模拟
沙粒沉积
strong wind area
high-speed railway subgrade
windbreak wall
numerical simulation
sand deposition
