A study on the seismic effect of the rubber damping layer in a shallow-buried and unsymmetrial pressure tunnel based on a shaking table test

Based on the shaking table model tests of a shallow-buried and unsymmetrial pressure tunnel with and without a rubber damping layer whose geometric similarity ratio is 1 : 20, the damping coefficient change laws of the rubber damping layer on the tunnel lining's acceleration and strain were studied and the seismic reduction effect of the rubber damping layer were evaluated. The research conclusions are as follows.(1) The rubber damping layer does not change the trend of the acceleration time history curve at the inverted arch, but significantly reduces its peak horizontal and vertical acceleration response. Regardless of the type of seismic wave, the intensity of seismic excitation, and the location of the tunnel lining, the rubber damping layer can significantly reduce the horizontal and vertical acceleration response.(2) Regardless of the type of seismic wave and excitation intensity, the horizontal and vertical acceleration damping coefficients of the left arch shoulder of the tunnel lining are much larger than those of the right arch shoulder, which is related to the tunnel being in an eccentric compression state. The impact of seismic wave types on the horizontal acceleration damping coefficient is greater than that on the vertical acceleration damping coefficient.(3) There is no significant correlation between the acceleration damping coefficient and the seismic excitation intensity, but from a trend perspective, as the excitation intensity increases, the damping coefficient tends to decrease.(4) Regardless of the type of seismic wave, the intensity of seismic excitation, and the location of the lining, the rubber damping layer has significant reduction effect on the maximum and minimum principal strains. There is no significant correlation between the maximum and minimum principal strain damping coefficients of the lining and the excitation strength, but overall, the damping coefficient shows a trend of weakening with the excitation strength.(5) The rubber damping layer can play excellent damping effect in the shallow-buried and unsymmetrial pressure tunnel, and its damping effect is closely related to seismic strength, material parameters of the damping layer, and stress environment. These conclusions can provide a certain reference for the application of rubber damping layer in tunnel engineering. © 2024 Chinese Vibration Engineering Society. All rights reserved.