Composite lining is often designed for the mountainous tunnels in high-intensity earthquake areas. The application of the buffer layer will bring more advantages, while the shock-absorbing mechanism is still unclear currently. In this paper, based on the Fourier-Bessel series expansion method, the dynamic stress concentration factor of composite lining tunnel with buffer layer subjected to plane SV waves in the half-space is obtained. Then, the influence of geometric and mechanical parameters of the buffer layer on composite lining was systematically analyzed. Finally, the correctness of the analytical solutions is verified by series shaking table tests and numerical simulations. Results suggest that the buffer layer can play the role of “redistributing” the seismic load, and it can effectively reduce the dynamic responses of secondary lining but amplify in primary support. There is an optimal interval of the stiffness and thickness for the buffer layer. When the stiffness ratio of the buffer layer to surrounding rock is 1/10 ∼ 1/50 or the ratio of buffer layer thickness to inner diameters of secondary lining is 1/40 ∼ 1/20, the shock-absorbing performance is remarkable. The general damage observations in tests show that the crown, arch springing, and invert of composite lining in case of no buffer layer are prone to cracking under a strong earthquake. The invert of the composite lining is more susceptible to be damaged after adopting the buffer layer. In general, the analytical results were consistent with experimental and numerical results. The above study results may provide theoretical support and experimental data for the seismic design of composite lining tunnels.

中文翻译：

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具有缓冲层的复合衬砌隧道的动力响应：分析和实验研究

复合衬砌通常设计用于高烈度地震地区的山区隧道。缓冲层的应用将带来更多的优势，而目前尚不清楚减震机制。本文基于傅里叶-贝塞尔级数展开法，获得了半空间平面SV波作用下带缓冲层的复合衬砌隧道的动应力集中系数。然后，系统地分析了缓冲层的几何和力学参数对复合衬砌的影响。最后，通过系列振动台试验和数值模拟验证了解析解的正确性。结果表明，缓冲层可以起到“重新分配”地震荷载的作用，可以有效降低次生衬砌的动力响应，但可以扩大主要支护。对于缓冲层，存在刚度和厚度的最佳间隔。当缓冲层与围岩的刚度比为1/10〜1/50或缓冲层厚度与二次衬砌内径之比为1/40〜1/20时，减震性能显着。测试中的一般损坏观察结果表明，在没有缓冲层的情况下，复合衬砌的拱顶，拱形弹簧和倒置在强地震下容易开裂。采用缓冲层后，复合衬里的内衬更容易受到损坏。通常，分析结果与实验和数值结果一致。