Evaluation of the Damping Layer between the Tunnel Lining and Surrounding Rock via a Shaking Table Test

This paper primarily investigates the protective effect of the damping layer in tunnel lining structures under dynamic loads. A series of shaking table tests was conducted to investigate the seismic response mechanism of tunnel linings and the influence of surrounding rocks using the Wenchuan earthquake (magnitude 8.0) as a reference. The results show that the effect of the damping layer protection measures is accurate using the efficiency evaluation method for the damping layer under seismic excitation. The lower the excitation acceleration is, the better the effect will be. In addition, the damping coefficient is introduced to optimize the efficiency evaluation method for the damping layer. Among the factors influencing the seismic response of lining structures, the type of surrounding rock has a significant impact while the thickness of the damping layer has a relatively lesser influence. In seismic intensity areas of equal magnitude, an increase in the damping layer thickness leads to a more noticeable effect. In the different seismic intensity areas, the difference in the protection effect with the change in thickness is no longer obvious with the increase in seismic intensity. Moreover, the presence of a damping layer alters the intrinsic vibration characteristics of the tunnel lining structure, creating a space for deformation between the lining and the surrounding rock.