盾构隧道在可液化场地中的地震响应分析

盾构隧道的装配式管片是其显著的结构特点,目前的抗震研究主要采用简化方法,少有能有效反映管片和接头细部特征的动力反应分析方法,对其在可液化场地中的地震响应规律也需要进一步研究。本文建立了一种精细化装配式管片结构计算模型,并基于砂土液化大变形统一本构模型,采用弹塑性有限元动力时程分析,分析了盾构隧道在可液化场地中的地震响应特征及规律。结果表明接头处响应是盾构隧道抗震的重要考虑因素。装配式管片结构相比于整体式结构柔度更大,受力较小,变形较大。在可液化场地中盾构隧道由于水平向作用力显著增加,在水平向被挤压,受力分布和抗震不利位置相比非液化场地有明显区别。

Seismic response analysis of shield tunnels in liquefiable soils

The prefabricated lining segments of shield tunnels are their most significant structural feature. The current researches on the seismic response of shield tunnels mainly adopt simplified methods, lack of dynamic response analysis, which can reflect the characteristics of tunnel segments and joints effectively. Further researches are needed to understand the seismic response of shield tunnels in liquefiable soils. A computational model for prefabricated tunnel linings is proposed in FEM program. A unified constitutive model for large post-liquefaction deformation of sand is used for liquefiable ground. The analysis results show that the joint is a key aspect of the seismic design of shield tunneling. The fabricated tunnel segment structure is more flexible than the monolithic structure under seismic loading. The tunnel is horizontally compressed in liquefiable soil, and the seismic response is distantly different from that in the non-liquefiable soils.