强风作用下带横隔面输电塔动力响应及破坏机理研究

Research on Dynamic Response and Failure Mechanism of Transmission Tower with Diaphragm under Strong Wind

摘要:

增设横隔面是对输电塔结构进行抗风加固的一种简单有效方式，但增设横隔面后输电塔的动力稳定性变化和破坏机理差异尚未明晰。以某220 kV同塔双回线路ZY2输电塔为研究对象，通过建立输电塔线耦联体系有限元模型，对比了增设横隔面前后的单塔及塔线体系的模态差异，验证了在靠近塔腿节间的交叉斜材处增设横隔面对于输电塔局部振型的抑制作用。采用随机风场模拟，计算不同风速下不同塔段处斜材增设横隔面前后轴力响应变化，结合动力不稳定区域理论计算斜材动力稳定性参数，将其与动力不稳定区域绘制在同一参数平面内并根据某一风速下斜材是否进入动力不稳定区域，来判断不同塔段处斜材增设横隔面前后的失稳风速。结果表明，合理增设横隔面最高可将杆塔破坏风速提高3 m/s。

Abstract:

Adding diaphragm is a simple and effective way to strengthen transmission tower structure. However, the change of dynamic stability and the difference of failure mechanism of transmission tower after adding diaphragms are still not clear. Taking the ZY2 transmission tower in a 220 kV common tower double circuit transmission line for example, the finite element model of tower-line coupling system is established to compare the modal differences between tower and tower-line system before and after adding diaphragms.The results show that adding diaphragms at the intersection diagonal near tower leg joints could suppress the local vibration mode of transmission tower. Then, random dynamic wind field is applied to calculate the axial stress response before and after adding diaphragms at different tower sections under different wind speeds. So that the dynamic stability parameters of diagonal braces are calculated based on the theory of dynamic unstable region, which are drawn in the same parameter plane with the dynamic unstable region. According to whether the diagonal brace parameters enter the dynamic unstable region at a certain wind speed, the wind speeds at instability before and after adding diaphragms at different tower sections can be determined, which shows that adding a diaphragm can increase the wind speeds at instability by up to 3 m/s.