摘要
以在建的贵州瓮马铁路北延伸线工程湘江特大桥为例,研究山区峡谷复杂地形下桥位处的风特性并指导桥梁抗风设计。采用逆向工程软件Imageware,使用曲面拟合的方式将高程数据转换成桥位附近直径8 km的地形曲面用于数值模拟和风洞试验分析。为解决模型边界的“人为峭壁”问题,通过采用改进的边界过渡段来减小地形模型中“人为峭壁”对山区桥位处风特性的影响。基于CFD数值模拟,通过改变速度入口边界位置来实现8种不同来流风偏角,研究桥轴线方向和风剖面监测点位置处的风特性。对有过渡段和无过渡段的地形模型开展风洞试验,研究横桥向风速、风剖面、风攻角以及桥梁总长1/4跨、1/2跨、3/4跨风剖面等风特性参数。研究结果表明:1)根据抗风规范确定的主梁设计基准风速较CFD方法确定的结果偏小;2)主梁高度处横桥向风速与来流入口基本风速相比,数值模拟和模型试验结果增幅分别为28%和10%;3)采用最优过渡段可使来流风速降低程度较无过渡段时小且风速保持较好;4)无过渡段时,“人工悬崖”会降低主梁高度处的横桥向风速。大跨度山区峡谷桥梁风特性数值模拟及试验研究得到了一些重要参数和变化规律,研究成果可为类似桥梁的设计研究提供一定的指导和参考作用。
Taking the Xiangjiang bridge of the north extension line of Guizhou Weng Ma railway under construction as an example, the wind characteristics of the bridge site under the complex terrain of mountain canyon were studied and the wind resistance design of the bridge was guided. The reverse engineering software Image ware was used to convert the elevation data into a topographic surface with a diameter of 8 km near the bridge site by surface fitting for numerical simulation and wind tunnel test analysis. In order to solve the problem of “artificial cliff ” at the boundary of the model, an improved boundary transition section was adopted to reduce the influence of “artificial cliff ” in the terrain model on the wind characteristics at the bridge site in mountainous area. First, based on CFD numerical simulation, eight different incoming wind deflection angles were realized by changing the boundary positions of velocity inlet, and the wind characteristics in the direction of bridge axis and in the position of wind profile monitoring points were studied. Second, wind tunnel tests were carried out on the terrain models with and without transition sections to study the cross-bridge wind speed, wind profile, wind angle of attack, and wind characteristic parameters such as 1/4 span, 1/2 span and 3/4 span wind profiles. The results show that: 1) the design reference wind speed of the main beam determined according to the wind resistance code is smaller than that determined by the CFD method;2) Compared with the transverse wind speed at the height of the main beam and the basic wind speed at the inlet, the increases of numerical simulation and model test results are 28% and 10%, respectively;3) The optimal transition section can reduce the incoming wind speed less than that without transition section, and the wind speed can be maintained better. 4) When there is no transition section,“artificial cliff”reduces the cross-bridge wind speed at the height of the main beam. The numerical simulation and experimental study of wind characteristics of long-span Canyon bridge in mountainous area disclosed certain important parameters and variation laws. The results can provide guidance and reference for the design and research of similar bridges to a certain extent.
作者
周继
王新国
刘志文
陈祥艳
ZHOU Ji;WANG Xinguo;LIU Zhiwen;CHEN Xiangyan(China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China;College of Civil Engineering,Hunan University,Changsha 410082,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2022年第4期995-1003,共9页
Journal of Railway Science and Engineering
基金
中铁第四勘察设计院集团有限公司科技研发项目(2018K008,2022K001)。
关键词
山区峡谷
风特性
数值模拟
风洞试验
边界过渡段
mountain canyon
wind characteristics
numerical simulation
wind tunnel test
boundary transition section
