典型峡谷Ⅴ型地貌下桥址区风特性  

Wind characteristics of bridge site under typical canyon V-shaped landform

作　　者：张玥[1] 刘子琦 石慧慧 ZHANG Yue;LIU Ziqi;SHI Huihui(College of Architecture and Civil Engineering,Xi’an University of Science and Technology,Xi’an 710054,China)

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054

出　　处：《西安科技大学学报》2024年第3期575-586,共12页Journal of Xi’an University of Science and Technology

基　　金：国家自然科学基金项目(52108246);长安大学中央高校基本科研业务费专项基金项目(300102210513)。

摘　　要：为得到山区峡谷典型Ⅴ型地形下的桥梁抗风设计的关键风特性参数,通过“数值风洞试验”建立模型,以实桥为工程背景构建三维地形网格,基于3种典型湍流模型和流体壁面粗糙度对桥位的风场特性进行分析,选取最优湍流模型和流体壁面粗糙度对该地形桥位处的风场特性进行分析;围绕两个影响桥址区风特性的地形参数(山体高度和夹角),阐明Ⅴ型峡谷地形下风特性参数的变化规律,并与现行规范进行对比,推算桥面设计基准风速。结果表明:该Ⅴ型峡谷地形的最佳湍流模型和流体壁面粗糙度分别为RNG k-ε和20 m;随着山体高度及山体夹角两参数的变化,风速增加幅度分别为2.37%~12.56%和1.24%~6.98%;山体高度及山体夹角两变参数下,梯度风高度分别为700 m和800 m左右;实际湍流强度大于规范中四类地表规范值,在离地高度40 m范围内,湍流强度更接近于D类地表。实际Ⅴ型峡谷桥址区不能简单按规范归为C类或D类地形,在设计风参数计算时应综合考虑规范和经验公式,还可借助模拟手段来提高其准确性。In order to obtain the key wind characteristic parameters for wind resistance design of Bridges in typical V-shaped terrain in mountain canyons,an model was established by the method of“numerical wind tunnel test”,a threedimensional terrain grid was constructed with real bridges as the engineering object,and the wind field characteristics of bridge sites were analyzed based on three typical turbulence models and fluid wall roughness.The optimal turbulence model and fluid wall roughness were selected to explore the wind field characteristics at the bridge site.From these two topographic parameters,mountain height and angle,which affect the wind characteristics of the bridge site,the variation law of the downwind characteristic parameters of the V-shaped canyon terrain is summarized,and the design reference wind speed of the bridge deck is calculated by comparing with the current norms.The results show that the optimal turbulence model and fluid wall roughness of the V-shaped canyon terrain are RNG and 20m respectively.With the change of mountain height and mountain angle,the increase of wind speed is 2.37%~12.56%and 1.24%~6.98%,respectively.Under the two variable parameters of mountain height and mountain angle,the gradient wind height is about 700 m and 800 m respectively.The actual turbulence intensity is greater than the standard values of the four types of surface in the specification,and the turbulence intensity is closer to the D type surface in the range of 40 m above the ground.The actual V-shaped canyon bridge site can not be classified as C or D terrain simply according to the code.The code and empirical formula must be considered comprehensively when designing the wind parameter calculation,and the accuracy could be improved by means of simulation.

关 键 词：风特性 Ⅴ型峡谷 数值风洞试验 湍流模型 地形参数 设计基准风速 

分 类 号：U442[建筑科学—桥梁与隧道工程]