考虑结构自重影响水下隧道通风竖井的水平振动特性研究

RESEARCH ON HORIZONTAL VIBRATION PROPERTIES OF UNDERWATER VENTILATION SHAFT OF TUNNEL CONSIDERING EFFECT OF SELF-WEIGHT OF STRUCTURE

在地震荷载下,竖井与围岩土水介质之间的动力相互作用是一个复杂的多场耦合问题。基于Winkler弹性地基梁理论,以附加质量的形式考虑动水压力,将土体视为支撑结构的弹性地基,通过建立欧拉梁挠曲控制微分方程,并借助传递矩阵法求解沿隧道轴向水平地震作用下竖井的内力与变形。通过与整体系统的ANSYS计算结果对比可知,所提出的模型与计算方法能够较好地模拟软土地基中竖井的动力特性。最后,对隧道与竖井接头刚度、自重影响下结构动内力沿竖井壁面的变化规律进行分析,由计算结果可知:改变接头的连接刚度能显著降低结构内力,提高结构安全度;对于大断面竖井的振动特性,自重影响显著,工程抗震设计中应该予以重视。

The seismic response of structure is a complex multi-field coupling issue considering the dynamic interaction effect of soil-water-tunnel shaft simultaneously. Based on the principle of Winkler foundation beam, and the hydrodynamic pressure is considered as the added pseudo mass,the deformation governing differential equation of the Euler beam is established according to the model in which the interface soil is simplified as spring modeling the soil-structure interaction,and the deformation and stress of structure are solved under the seismic loading using the transfer matrix method. Furthermore,a comparative analysis is employed by the usual software ANSYS,it is found that,the introduced foundation beam model and calculation method can reflect the actual vibration characteristics of tunnel shaft in soft soil effectively. Finally,the distribution of internal force along the shaft influenced by the connection joint and self-weight of structure is analyzed,through the discussion of parameters,it is concluded that,the internal force of structure can be decreased by reducing the connecting stiffness between tunnel and shaft,and the degree of structural security is increased;meanwhile,the factor of self-weight of structure is extremely important for the vibration properties of partially embedded tunnel shaft with large cross section,which can not be ignored by designers.