强风作用下输电塔线体系连续性倒塌分析

Cascading Failure Analysis of Transmission Tower–Line System Under Strong Wind

为分析强风作用下输电塔线体系连续性倒塌的过程,将已发生破坏的输电塔作为薄弱塔,采用等效位移的方式考虑薄弱塔倒塌对挂线点空间位置的影响,计算相邻输电塔(目标塔)在薄弱塔多组倒塌特征变量组合工况下的响应和破坏特征,确定对目标塔具有最大影响的薄弱塔倒塌特征变量.结果表明:在发生连续性倒塌时,目标塔的破坏包括近薄弱塔侧的塔身破坏和塔头破坏2种形式;目标塔近薄弱塔侧背风面主材应力比最高,斜材应力比一直较低;塔身下部斜材失稳与主材应力的持续增大是目标塔整体倒塌的最直接原因;薄弱塔的倒塌过程持续时间是目标塔是否破坏的主要控制变量.

In order to analyze the cascading failure of the transmission tower–line system under strong wind,this paper took the collapsed transmission tower as the weak tower and used equivalent displacement to consider the influence of weak tower collapse on the spatial location of suspension points.The responses and failure characteristics of the adjacent transmission tower(target tower)under multiple combined groups of the weak tower collapse parameters were calculated,and the weak tower collapse parameters with the greatest influence on the target tower were determined.The results show that when cascading failure happens,the failure of the target tower includes two types,the failure of the tower body near the weak tower and the failure of the tower head.The main bracing on the leeward side of the weak tower has the highest stress ratio.The stress ratios of diagonal bracings are always low.The most direct causes of the overall collapse of the target tower are the instability of diagonal bracings at the lower part of the target tower and the continuous increase in stress of the main bracing.The duration of the weak tower collapse is the main control variable for the failure of the target tower.