大型高耸钢筋混凝土冷却塔属于典型的风敏感型结构,近年来在地震、飞机撞击、爆破等极端外部作用下动力响应研究也得到了工程界的广泛关注。土-结构动力相互作用效应(Soil Structure Interaction,SSI)对于大坝、桥梁等类型工程结构地震响应的影响研究成果较为丰富,而对冷却塔结构体系的影响程度方面很少涉及。依据弹性波动理论结合有限单元法,建立和推导了考虑土-结构动力相互作用的三维黏弹性人工边界模型和公式,并通过半空间自由场模型验证该地震动输入方法的准确性。以国内实际工程项目——某火电厂大型冷却塔为研究背景,以通用有限元程序ANSYS为平台,分别建立了冷却塔刚性地基模型、无质量地基模型和黏弹性人工边界模型,开展模态分析及弹性时程分析,研究不同计算模型相应的动力特性及内力变化,探讨了土-结构动力相互作用的影响规律。研究结果表明:考虑刚性地基,冷却塔结构体系自振频率分布十分密集,绝大多数振型为环向谐波和子午向谐波组合的局部振型;考虑弹性地基后,结构的自振频率略有降低,整体振型较早出现。通过时程分析可知,采用黏弹性人工边界模型,考虑无限地基辐射阻尼效应,与刚性地基模型相比,塔筒的绝对加速度最大值降低43.4%,塔筒沿子午向弯矩轴力幅值降低约50%,而环向内力却均显著提高,X支柱内力幅值降低约20%~50%.因此,在进行冷却塔地震响应分析时,土-结构动力相互作用的影响不可忽视。 Large towering reinforced concrete cooling tower belongs to the typical wind-sensitive structure. In recent years, the research of dynamic response under the extreme external action of earthquake, aircraft impact and blasting has also drawn extensive attention in engineering field. Soil Structure Interaction (SSI) has rich research results on the seismic response of dam, bridge and other types of engineering structures, but rarely affects the degree of influence of the structural system of the cooling tower. According to the theory of elastic wave and the finite element method, a three-dimensional viscoelastic artificial boundary model and formula considering the soil-structure dynamic interaction are established and verified. The accuracy of the input method of the ground motion is verified by half-space free-field model. Taking the domestic actual project, a large-scale cooling tower of a thermal power plant as a research background, a rigid foundation model, a massless foundation model and a viscoelastic artificial boundary model of a cooling tower are established respectively by using the common finite element program ANSYS. Modal analysis And elastic time history analysis, the corresponding dynamic characteristics and internal force changes of different calculation models are studied, and the influence laws of soil-structure dynamic interaction are discussed. The results show that, considering the rigid foundation, the self-vibration frequency distribution of the cooling tower structure system is very intensive, most of the vibration modes are the local vibration modes of the combination of the circular harmonic and the meridional harmonic. After considering the elastic foundation, the natural frequency of the structure Slightly lower, the overall modeler appeared earlier. According to the time-history analysis, considering the viscoelastic artificial boundary model and considering the damping effect of infinite foundation, the absolute maximum acceleration of the tower is reduced by 43.4% compared with the rigid foundation model, and the axial force amplitude along the meridional axis of the tower is reduced About 50%, while the internal forces are significantly increased, and the X-pillar internal force amplitude is reduced by about 20% -50%. Therefore, the influence of soil-structure dynamic interaction can not be neglected when analyzing the seismic response of cooling tower.