在通用有限元软件ANSYS中建立了220kV猫头塔有限元模型,分别采用静力和动力方法分析了基础不均匀沉降、倾斜和水平滑移工况的铁塔杆件内力,计算了基础突然变形时输电铁塔结构的动力冲击系数。结果表明,基础变形过程中输电铁塔塔腿斜材应力变化幅度最大并最先发生破坏。铁塔杆件轴力峰值发生在基础沉降的初始时刻附近,而阻尼比对峰值影响不大,阻尼比分别为0.01和0.05时,塔腿主材轴力峰值仅相差约3.5%。对于经过地表变形剧烈的采空区输电线路,基础突然变形对输电铁塔结构的动力冲击效应显著。考虑基础变形动力冲击效应后,不均匀沉降工况下塔腿斜材应力比增大50%以上,单侧倾斜和水平滑移工况的塔腿斜材应力增大幅度超过100%。
The finite element analysis model of a 220kV cat-head transmission tower was established by using the general FEA software ANSYS. The axial forces of tower members under different load cases were analyzed by the static method and dynamic method respectively. Three typical load cases were taken into account, including the non-uniform settlement, inclination and horizontal slip of the tower foundation. The dynamic impact factors of the axial forces of tower members with a sudden foundation deformation were calculated. It is shown that the stress in the diagonal member located at the tower leg varies greatestly and fails earlistly in the process of foundation deformation. The peak values of tower member forces occur near the initial time of the foundation settlement, while the effect of damping ratios on the peak values is not significant. When the damping ratio is valued as 0.01 and 0.05, the difference between the peak axial forces of the leg main member different is only about 3.5%. For the transmission lines in the mining subsidence areas with dramatic surface deformations, the dynamic impact effect of sudden foundation deformations on transmission tower structures is significant. By considering the dynamic impact effect, the stress ratio of the diagonal member located at the tower leg under non-uniform settlement is increased by more than 50%. The increasing extents even exceed 100% in the single side inclination case and the horizontal slip case.