Shock Reduction Techniques for a Submarine Tunnel

Abstract

Considering the effects of seepage and dynamic pressure, defining a rock mass as a saturated porous media, and using the finite element method, a dynamic fluid–structure interaction model of a subsea tunnel with a viscous spring artificial boundary is established. Adopting rubber and foam concrete as shock absorption layers and inputting both horizontal and vertical earthquake waves, the time history curves of the first principal stress at key points in the secondary lining structure are comparatively analyzed based on the presence and absence of shock absorption layers. The principal stress peaks are also analyzed. The damping effect of the shock absorption layer is studied. The results show that the peak and principal stresses at the main parts of the tunnel lining structure decrease after the shock absorption layer is established. Obvious decreases occur in the vault and inverted arch. A certain degree of peak stress reduction is also observed after the shock absorption layer is established. Establishing the shock absorption layer does not change the spectrum characteristics of the tunnel structure. Foam concrete shock absorption is recommended because the damping effect of foam concrete is more observable than that of rubber.