Potential earthquake-induced damage to overlapped tunnels probably occurs during the operation and maintenance of mountain tunnel engineering, especially in the seismically active zone. This study investigated the dynamic response and the failure characteristics of the parallel overlapped tunnel under seismic loadings by employing shaking table tests. The failure mode of the parallel overlapped tunnels was analyzed through macroscopic test phenomena. The dynamic responses of the surrounding rock and tunnel lining were evaluated by acceleration and dynamic strain, respectively. In particular, wavelet packets were used to investigate the spectrum characteristics of the tunnel structure in depth. The failure process of the model can be divided into three stages. The upper-span and the under-crossing tunnels showed different failure characteristics. Additionally, the lining damage on the outer surface of the tunnel mainly occurred on the right side arch waist and the left side wall, whereas the lining damage on the inner surface of the tunnel mainly appeared on the crown and invert. Wavelet packet energy results showed that the energy characteristic distributions of the upper-span and the under-crossing tunnels were not consistent. Specifically, the energy eigenvalues of the crown of the upper-span tunnel and the invert of the under-crossing tunnel were the largest, which should be considered to be the weak parts in the seismic design.

中文翻译：

---

地震荷载作用下平行叠合隧道的动力响应振动台试验

在山地隧道工程的运营和维护过程中，特别是在地震活动区，可能会发生地震对重叠隧道的潜在破坏。本研究采用振动台试验研究了平行叠层隧道在地震荷载作用下的动力响应和破坏特性。通过宏观试验现象分析了平行重叠隧道的破坏模式。围岩和隧道衬砌的动力响应分别通过加速度和动态应变进行评估。特别是，小波包被用于深入研究隧道结构的频谱特征。模型的失效过程可分为三个阶段。上跨和下穿隧道表现出不同的破坏特征。此外，隧道外表面衬砌损伤主要发生在右侧拱腰和左侧墙体，而隧道内表面衬砌损伤主要发生在拱顶和内底。小波包能量结果表明，上跨隧道和下交叉隧道的能量特征分布不一致。具体而言，上跨隧道拱顶和下穿隧道内底的能量特征值最大，应视为抗震设计中的薄弱部位。小波包能量结果表明，上跨隧道和下交叉隧道的能量特征分布不一致。具体而言，上跨隧道拱顶和下穿隧道内底的能量特征值最大，应视为抗震设计中的薄弱部位。小波包能量结果表明，上跨隧道和下交叉隧道的能量特征分布不一致。具体而言，上跨隧道拱顶和下穿隧道内底的能量特征值最大，应视为抗震设计中的薄弱部位。