【摘要】 下击暴流是一种较为常见的极端风气候，对输电线路具有较强破坏性。开展下击暴流风场及其风效应实测研究，对于深入理解风场特征并合理开展结构抗雷暴风设计具有重要意义。为此，基于浙南地区的输电塔实测项目，筛选出疑似下击暴流风速数据，分析了雷暴风的平均风速、脉动风速、湍流度及脉动风功率谱特性，并进一步研究了非稳态下击暴流作用下输电塔的动力响应特性。研究结果表明：实测下击暴流的时变平均风速可以用移动平均法采用60 s平均时距快速准确地提取；实测下击暴流的脉动风速在峰值风速时段的湍流强度为0.2左右，接近于高斯分布；对两条风速时程的时变湍流强度分析，发现实测风速越大，在风速降低风场减弱时的湍流强度越大；结构响应主要由前两阶模态提供；利用非线性规划遗传算法通过有限测点的风速时程记录能够良好地反演出风场参数，重构风场较好地还原实测风场风速时程；重构风场作用下的输电塔动力响应与实测数据趋势一致、幅值接近。更多还原

【Abstract】 Downburst is common extreme wind climate, which is destructive to transmission lines. It is of great significance to study the wind field and wind effect of downburst in order to understand the characteristics of wind field and carry out the design of structure anti-thunder storm reasonably. This study is based on the field measurement project of transmission towers in southern Zhejiang Province. Suspected downburst wind speed data were selected. The measured model of a transmission tower was established, and the wind-induced vibration response of transmission tower under the measured wind field was analyzed. The results show that the measured time-varying average wind speed of downburst can be extracted quickly and accurately by using the moving average method and using the average time distance of 60 s. The turbulence intensity of the pulsating wind speed during suspected downburst events, particularly during periods of extreme wind speed, was measured to be approximately 0.2, indicating a close resemblance to a Gaussian distribution. Upon analyzing the temporal variation of turbulence intensity in two wind speed time series, it was observed that the turbulence intensity tends to increase as the measured wind speed becomes larger, especially when the wind field weakens during wind speed reductions. The measured inclination, second and top layer acceleration responses are mainly provided by the first two orders of modes. The foot strain of transmission tower is greatly affected by temperature in a long-time range and wind speed in a local short time range. The structural response is mainly provided by the first two orders of modes. Using the nonlinear planning genetic algorithm to record the wind speed timescale through a limited number of measurement points can be a good inverse performance of the wind field parameters, and the reconstructed wind field is better restored to the measured wind field wind speed timescale. The dynamic response of the transmission tower under the effect of the reconstructed wind field is close to the measured data with the same trend and magnitude.更多还原