滑坡区输电塔线体系抗变形能力及动力响应分析

滑坡区输电线路由于风荷载作用产生的附加内力,承受地表变形能力大幅降低,极易发生断线、倒塔等事故,因此对输电塔线体系在风荷载和地表变形作用下进行安全性研究具有重要意义。以滑坡区某220 kV输电线路为研究对象,建立两塔三线体系有限元模型,并通过Kaimal谱和线性滤波法建立风荷载模型,对输电塔线体系在无风工况下的抗变形能力和设计风速工况下的动力响应进行分析。结果表明,在无风工况下,塔腿的沉降变形对输电塔线体系的影响最严重,铁塔发生屈服的杆件主要位于塔脚点、第一横隔材与斜材连接点以及第一横隔材与主材连接点;在设计风速条件下,塔线体系大部分工况仅能承受正常无风工况下的塔腿变形的60%～80%,垂直于线路方向的双腿沉降工况抗变形能力下降得最严重,仅能承受正常工况的30%,同时,塔线体系导、地线的应力以及塔头的位移均会在动力响应达到峰值时超限,从而导致塔线结构失效。

Anti - deformation ability and dynamic response analysis of transmission tower-line system in landslide area

Due to the additional internal force generated by wind load, the power transmission lines in the landslide area are greatly reduced in their ability to bear ground deformation, and are prone to accidents such as line breakage and tower collapse. Therefore, it is of great significance to study the safety of the power transmission tower line system under wind load and ground deformation. Taking a 220kV transmission line in landslide area as the research object, the finite element model of two towers and three lines was established, and the wind load model was established by the method of Kaimal spectrum and linear filtering. The deformation resistance of the transmission tower line system under windless condition and the dynamic response under the design wind speed condition were analyzed by applying deformation to the tower legs. The results show that the settlement deformation of the tower legs has the most serious effect on the transmission tower line system under no wind condition. The yielding bar of the tower is mainly located at the tower foot point, the connection point between the first diaphragm and inclined material, and the connection point between the first diaphragm and the main material. Under the condition of design wind speed, the working condition of tower line system most only can tower leg deformation under normal working conditions of 60% ~ 80%, and subsidence in vertical direction of the line legs working condition of resistance to deformation ability of the most serious, can withstand the normal working condition of only 30%, at the same time, the tower line system of the conductor and ground stress and displacement of tower head will overrun when dynamic response peak, resulting in line tower structure failure.