不滑移状态下深埋圆形隧道地震响应研究
Seismic Response of Deep-buried Circular TunnelsUnder No-slip Interface Conditions

地下结构的地震响应主要取决于由地震波传播产生的土体变形与土结相互作用。剪切波传播过程中将会引起隧道衬砌的椭圆化变形，进而降低衬砌有效承载力。剪切波作用下的深埋圆形隧道可认为处于均质的纯剪状态，基于相对刚度法的拟静力解析解可充分考虑土结相互作用对隧道结构内力的影响。基于此，本文将通过有限元数值分析获得的自由场地地基变形引入不滑移状态下深埋圆形隧道内力求解公式，并结合二维和三维数值模拟途径，将动力分析结果与解析解结果进行对比分析，以评价各种解析方法的适用性和数值途径的可靠性。
The seismic response of underground structures is mainly determined by the soil deformation induced by seismic wave propagation and soil-structure interaction. The ovalization of tunnel lining during the process of shear wave propagation reduced the effective bearing capacity of lining. The resulting change of shape of tunnel section generates circumferential strains in the tunnel lining, which can cause cracking and/or crushing of concrete and reduce the carrying capacity of the lining. Since the dimension of a typical lining cross-section was small, in comparison to the wavelength of the dominant ground motion, and the inertial effects in both the lining and the surrounding soil were relatively small, therefore, the response of the cross-section induced by seismic motions could be considered as a response to an imposed uniform strain field. Transversal behavior is usually studied by analyzing the response of the cross-section to an imposed uniform strain field by using the pseudo-static approach. In general, most pseudo-static approaches are developed based on the relative stiffness method, which can take soil-structure interaction into account. In this paper, the available closed-form solutions under no-slip interface conditions (no relative shear displacement), which are developed based on the relative stiffness methods, were reviewed, and then the seismic response of a circular tunnel was analyzed, both analytically and numerically, in order to investigate the seismic response of tunnels subjected only to shear waves. The research is of great interest for evaluating the reliability of analytical solutions as well as the reliability of numerical approaches.