特高压单柱拉线塔受力特性及拉线初始预应力对其影响的研究

The Influence of Initial Guy Cable Prestress on UHV Transmission Line Single Mast Guyed Tower's Mechanical Properties

特高压拉线塔具有良好的应用前景,拉线的初始预应力对拉线塔受力至关重要。建立了特高压直流输电线路工程中的单柱拉线塔非线性有限元模型,分析拉线的受力特点,提出了影响拉线塔力学特性的拉线临界预应力的概念,研究分析了拉线初始预应力对单柱拉线塔受力特性的影响规律。结果表明:在大风荷载状态下,当拉线初始预应力小于拉线临界预应力时,随初始预应力的增大,拉线塔节点位移减小,拉线工作应力、杆件轴力、主柱支座反力基本不变;当拉线初始预应力大于拉线临界预应力时,随初始预应力的增大,拉线塔节点位移基本不变,而拉线工作应力、杆件轴力、主柱支座反力等均线性增大;大风荷载状态拉线临界预应力约为仅迎风侧拉线受拉时工作应力的一半,拉线的初始预应力应在比临界预应力小的范围内选择。

The UHV transmission line guyed tower has good prospect for application. The guy cable＇s pre-stress is crucial to tower＇s mechanical properties. The nonlinearity finite element model of the single mast guyed tower in UHV DC transmission lines was built. Mechanical characters of the guy were analyzed, and the concept of critical pre-stress was presented. The influence of the guy cable＇s pre-stress on the guyed tower＇s mechanical properties was studied. The result shows that： when the initial guy cable＇s pre-stress is less than critical stress, the nodes＇ displacement decreases with the growth of initial guy cable pre-stress, while the guy cables＇ work stress, tower＇s support force and leg member＇s axial force are almost kept unchanged. However, when the initial guy cable＇s pre-stress is greater than the critical guy cable＇s pre-stress, the nodes＇ displacement is nearly kept the same, and with the growth of the initial guy cable＇s pre-stress, the guy cables＇ work stress, tower＇s support force and leg member＇s axial force have a linear increase. The critical stress is about half of the windward guy cable＇s work stress, and in the actual projects the initial guy cable＇s pre-stress should be less than the critical guy cable＇s pre-stress.