水下盾构隧道抗震设计分析方法的适应性研究

 针对断面大、水头高，结构复杂的水下盾构隧道，通过分析其在横向和纵向结构特点，提出了合理的抗震设计方法。在地层条件较均匀的横断面，通过成层重复反射理论，计算出工程场地地层的实际地震响应，采用反应位移法对隧道典型断面进行地震反应分析，再将其结果与静力计算结果叠加后作为抗震设计的依据。纵向则考虑线状结构特点、沿隧道纵向地层的不均匀性、地震行波效应和边界效应等方面的因素，应用三维时程响应法加以计算分析。对2种方法的特点、适用条件和分析流程进行了系统阐述，并将其应用于越长江盾构隧道工程，揭示了该典型水下盾构隧道的动力响应特征及抗震的薄弱部位。

APPLICABILITY STUDY ON ASEISMIC DESIGN METHOD OF SUBMARINE SHIELD TUNNEL

Based on structural features in both transverse and longitudinal directions，a reasonable aseismic design method for structurally complicated subriver shield tunnels with large cross-section and deep underwater pressure is proposed. For the design of transverse direction of tunnel with relatively regular ground that is different from the hypothesis of boundary displacement sine wave distribution mode，practical seismic responses from the ground where the tunnel will be constructed have been calculated according to the theory of ground stratification reflection theory. Using seismic deformation method，the seismic response of a typical section of the tunnel was analyzed. The result was used in combination with static calculations as support for aseismic designs. For the longitudinal direction，the 3D time-domain response method should be used due to the requirement of considering linear structural features，the irregular ground along longitudinal direction of the tunnel，seismic traveling wave effects，and boundary effects，etc.. The features，applications，and analytical process of these two methods are discussed. The design method has been applied to a shield tunnel crossing the Yangtze River，and the seismic behaviors and the aseismic-weaker parts of this typical subriver shield tunnel are also indicated.