结合位于鄂西山区的四渡河峡谷大桥的抗风设计研究,在桥位现场用超声风速仪实测脉动风速时程数据,分析山区深切峡谷风的湍流特性。基于10 min平均时距划分子样本,统计分析峡谷桥位的风速、风向、阵风因子、湍流度、积分尺度和功率谱密度函数。结果表明:该桥所在的山区深切峡谷地形导致风的湍流脉动强度明显增大,表征涡旋大小的湍流积分尺度减小;湍流度随平均风速的增大而减小,积分尺度随平均风速的增大而增大;由实测数据拟合的山区峡谷功率谱密度函数模型存在低频迟滞区,山区峡谷风的湍流特性与规范推荐模型有较大差别。
Based on wind-resistance design research of Sidu River Valley Bridge site,wind fluctuating velocities were measured by ultrasonic anemometers.Turbulence characteristics of mountainous wind at bank of the deep-cut valley were analyzed.Wind speed and direction,gust factor,turbulence intensity,integral scale and power spectral density were analysed on the basis of 10-minute-spectral gap sub-sample data.The results show that the deep-cut mountainous river valley terrain causes much higher turbulence level and breaks down the turbulence integral scale of vortices.Turbulence intensity decreases and integral scale increases with increase of mean wind speed.Power spectral density function model by field measurement data fitting presents spectral lag in low frequency range and differentiates from the code-recommended models.