考虑行波效应的盾构隧道纵向抗震分析

Longitudinal Aseismic Analysis of Shield Tunnel Considering Traveling Wave Effect

为研究盾构隧道结构和接头处纵向抗震能力,采用纵向等效刚度的地层-结构模型,考虑行波效应,计算了不同激励波型下隧道纵向动力响应,验算了在弯矩和轴力协同作用下盾构隧道衬砌环缝张开量及螺栓应力。计算表明:考虑行波效应下地震波激振时,剪切波作用下隧道纵向以承受水平面内弯矩为主;45°剪切波作用下隧道纵向同时承受轴向拉压力和水平竖直面内弯矩;在压缩波作用下,隧道纵向主要承受轴向拉力和压力,同时存在一定的竖平面内弯矩,对隧道结构安全性更不利,易使盾构隧道结构发生破坏。

An analysis of longitudinal seismic resistance of shield tunnel structures and segment joints is conducted using a ground-structure model to calculate the longitudinal dynamic response under various excitation wave conditions,and the longitudinal equivalent stiffness and traveling wave effect are involved.The annular joint opening and bolt stress of the shield tunnel lining under the combined action of bending moment and axial force are verified.Based on the calculation results,when considering the seismic wave excitation under the traveling wave effect,the longitudinal direction of the tunnel under the shear wave is mainly subjected to the bending moment in the horizontal plane.The longitudinal direction of the tunnel under the 45°shear wave is subjected to axial tensile pressure and the bending moment in the horizontal and vertical planes.In contrast,the longitudinal direction of the tunnel under the compressional wave is mainly subjected to the axial tensile force and pressure.At the same time,there is a specific vertical in-plane bending moment,which is more unfavorable to the tunnel structure and more likely to damage to the shield tunnel structure.