Earthquake damage of underground structure indicates that the seismic response of tunnels is affected by the earthquake source, propagation medium, and local tunnel-surrounding rock system. Current research on the seismic response of tunnels primarily focuses on local tunnel systems, posing a challenge in comprehensively assessing the impact of earthquakes on tunnel group. This study introduces a theoretical seismological approach for the seismic response analysis of tunnels and presents a novel methodology for assessing the response. The proposed approach uses a kinematic seismic source as the earthquake source, assuming the geological strata as a layered medium and a tunnel as a point within a semi-infinite space. The wavenumber-integral method was used to solve for the seismic wave field and strain. To reflect the followability of underground structure to the surrounding rock deformation, we improved it and derived an analytical formula for the strain. The 2022 Menyuan earthquake was considered as a case study; the seismic damage to tunnels along the Lan-Xin Railway was analyzed using the proposed approach. The results confirm that there is a strong correlation between tunnel damage and free-field strain induced by earthquakes. The theoretical influence range of earthquake on tunnel was investigated using the diameter deformation ratio of the tunnel as an indicator. For tunnels embedded in a grade III rock mass, the theoretical range was approximately 7.0 km on both sides of the fault. For tunnels embedded in a grade rock mass, the theoretical range can reach up to 25.9 km. The results also revealed that tunnels on the hanging-wall side of the fault had a more significant impact than those on the foot-wall side, although their affected areas were smaller.

中文翻译：

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基于运动震源的多层介质隧道地震反应分析新工具


地下结构地震损伤表明隧道的地震响应受到震源、传播介质和局部隧道围岩系统的影响。目前对隧道地震响应的研究主要集中在局部隧道系统，这给综合评估地震对隧道群的影响带来了挑战。本研究介绍了用于隧道地震响应分析的理论地震学方法，并提出了一种评估响应的新方法。所提出的方法使用运动震源作为地震源，假设地质地层作为层状介质，隧道作为半无限空间内的一个点。采用波数积分法求解地震波场和应变。为了反映地下结构对围岩变形的跟随性，对其进行了改进，推导出应变解析公式。以2022年门源地震为例；采用该方法对兰新铁路沿线隧道的地震破坏进行了分析。结果证实隧道损伤与地震引起的自由场应变之间存在很强的相关性。以隧道直径变形率为指标，研究地震对隧道的理论影响范围。对于埋藏在Ⅲ级岩体中的隧道，断层两侧的理论范围约为7.0公里。对于埋入等级岩体中的隧道，理论范围可达25.9公里。研究结果还表明，断层上盘侧隧道的影响比下盘侧隧道的影响更为显着，尽管其影响范围较小。