大型冷却塔环基受力性能的影响因素分析

Analysis of Influencing Factors of Mechanics Performance of Hoop Base for Large Cooling Towers

以某大型冷却塔结构为例,建立考虑地基土影响的三维有限元分析模型,讨论了不同地基土条件、地基刚度变化、塔筒开孔大小及位置对冷却塔环基受力性能的影响。分析结果表明:桩基上冷却塔的基频小于岩基上冷却塔的基频,并且某些整体振型会提前被激发出来;环基轴力主要受径向刚度和环向弯曲刚度影响,其变化和径向刚度变化成反比,和环向弯曲刚度变化成正比,并且开始时增幅较大,随着弯曲刚度继续增大,其增幅变小;径向弯矩由环向弯曲刚度控制,其变化趋势和环基轴力正好相反;开孔会使竖向弯矩增大,并且随着孔洞直径增大而变大。

Taking the large cooling tower as an example, the 3-D finite element analysis model considered the influence of subgrade soil was established. The influencing factors of mechanics performance of hoop base for large cooling powers, such as different subgrade soil conditions, the variety of base stiffness as well as the size and position of open hole were discussed. The analytical results show that the basie frequency of the pile foundation is less than the basic frequency of rock foundation for cooling powers, and the whole vibration modes will be excited. Meanwhile, the axis forces are mainly influenced by radial stiffness and hoop-bending stiffness, and the variety is inverse ratio with the radial stiffness, and is direct ratio with hoop bending stiffness, the amplitude is greater at the beginning, and then diminishes with the augment of bending stiffness. Finally, the radial moment value is controlled by hoop bending stiffness, and its variation tendency is opposite with the axis fo the augment of the vertical moment value, which rce, at the same time, the open is increased with the augment of hole diam cause eter of the hole.