金沙江典型峡谷桥址风谱特性  

Wind spectrum properties at a typical canyon bridge site in the Jinsha River

作　　者：郭黎明 曾加东 张志田 GUO Liming;ZENG Jiadong;ZHANG Zhitian(School of Civil Engineering and Architecture,Hainan University,Haikou 570228,China)

机构地区：[1]海南大学土木建筑工程学院,海南海口570228

出　　处：《海南大学学报(自然科学版)》2024年第4期421-428,共8页Natural Science of Hainan University

基　　金：国家自然科学基金重点项目(51938012);国家自然科学基金项目(52268073)。

摘　　要：西部山区峡谷地带桥梁设计风参数是一个相关规范未解决而有待研究的问题.根据测风塔的长期观测数据,对拟建的奉科金沙江大桥桥址所处的山区峡谷风场特性进行研究,经统计分析得到桥址的平均风速、风向和湍流强度,并以10 m·s^(-1)为界限,分析高风速脉动风功率谱密度函数.结果表明:平均风速沿高度变化规律与规范描述基本相符,但极大风速沿高度的变化与规范描述明显不符;峡谷地形对风向分布以及湍流特性具有显著影响,沿峡谷走向的风速样本湍流强度明显低于其他风向的湍流强度,湍流强度表现出明显各向异性;同样沿峡谷走向,西北风向(120°~165°)时来流湍流强度最小,整体横风向湍流强度大于规范所给数值;von Karman谱和Harris谱与实测顺风向谱最为接近,但在高频区域仍低于实测顺风向谱;Panofsky谱与Lumely-Panofsky谱在峰值上与实测竖向谱有所偏移,Lumely-Panofsky谱偏移程度更大.在低频区两个谱值均小于实测竖向谱值,高频区二者均大于实测竖向谱.与Lumely-Panofsky谱相比Panofsky谱与实测竖向谱更加吻合.Wind parameters used for the wind-resistant design of the bridges in western canyons remain an un-solved issue by the relevant standards and hence need to be investigated.In the report,based on the long-term observations from wind measurement towers,the characteristics of the wind field in the mountainous canyon where the proposed Fengke Jinsha River Bridge was located were analyzed,the average wind speeds,wind direc-tions,and turbulence intensities at the bridge site were obtained by the statistical analysis,and the power spec-tral density functions were analyzed at wind speeds which was higher than a threshold of 10 m·s^(-1).The results in-dicated that the profile of the average wind speed varied with height was generally consistent with the specifica-tions,however,the profile of the peak wind speed deviated significantly from the specifications.The canyon to-pography had a significant influence on the wind direction distribution and turbulence characteristics.The turbu-lence intensities of the wind samples along the canyon direction were significantly lower than that of the wind samples from the other directions,which exhibited the clear anisotropy.Along the canyon direction,the turbu-lence intensity of the flow was minimum in northwest direction(120°~165°),the overall crosswind turbulence in-tensity exceeded the values suggested by the specifications.The von Karman and Harris spectra were the closest to the measured along-wind spectrum,but still lower than the measured along-wind spectrum in the high-fre-quency region.The peak values of both the Panofsky and Lumely-Panofsky spectra were difference slightly from the measured vertical spectrum,the latter showed a higher deviation than the former.In the low-frequency re-gion,the values of both the Panofsky and Lumely-Panofsky spectra were lower than that of the measured vertical spectrum.In the high-frequency region,the values of both the Panofsky and Lumely-Panofsky spectra were high-er than that of the measured vertical spectrum.Compared with the Lumely-Pan

关 键 词：大跨度桥梁 风特性 现场实测 功率谱 峡谷地形 

分 类 号：P412.16[天文地球—大气科学及气象学]