遮挡山体对输电塔线体系风振疲劳的影响

山地地形中遮挡山体使风场更加复杂,对结构的风致响应也造成了较大影响。为此,本文首先基于风洞试验研究了遮挡山体的不同坡度、高度以及间距对受扰山体风场特性的影响，通过对13种工况中受扰山体的山顶和背风面加速比的变化情况进行分析,得到了遮挡山体对风场的影响规律。然后，根据风向风速实测数据计算出风向风速联合分布的统计概率，结合时域和频域疲劳累积损伤理论，提出了输电塔线体系风振疲劳的建议算法。最后，基于试验数据及统计概率对某特高压输电塔线体系在各工况的风场条件下分别进行了风振疲劳分析，结果表明：输电塔疲劳寿命随遮挡山体坡度呈先增后减的复杂变化趋势，山体背风面山脚疲劳寿命最短；坡度相同而高度不同的遮挡山体未对输电塔疲劳寿命造成明显变化；遮挡山体间距较小时输电塔疲劳寿命最短，但随着遮挡间距增加受扰山体风场逐渐趋于稳定，疲劳寿命随之延长。

Effect of occluding hills on Wind-Induced Fatigue of Transmission Tower-Line Coupled System

In hilly terrain, the characteristics of wind field are distinct from the flat terrain wind field due to the interference of occluding hills, which make the wind-induced response of structures to be affected significantly. In this work, according to three kinds of different occluding hill terrains, the wind field of interfered hills is researched by the wind tunnel test. The effects of varies of different conditions are considered in the research, such as 5 different slopes of occluding hills, 3 different heights of occluding hills, and 5 kinds of occlusion distances between occluding hills and interfered hills. The rules of effects on the wind field of interfered hills by occluding hills are obtained. Furthermore, the joint statistical probability for both wind direction and wind speed is calculated by analyzed the record data. Meanwhile, the method for calculating the wind-induced fatigue of transmission tower-line coupled system is proposed by combined with the joint statistical probability and the time domain and frequency domain fatigue cumulative damage rules. At last, based on the proposed method and test data, the wind-induced fatigue of ultra-high voltage transmission tower-line coupled system is also studied. It can be found that the fatigue life of transmission tower is increased firstly and then decreased with the increasing slopes of occluding hills, and the fatigue life at hill base in lee side is shortest; the height of occluding hill has little effect on the fatigue life when the slope isn’t changed; the occlusion distance is shorter and the fatigue is also shorter, but the life is gradually becoming longer when the occlusion distance is increased.