Seismic response of deep circular tunnels subjected to P-waves: Axial and transverse compression-extension

Abstract

Body waves can intersect a tunnel at various angles and thus induce complex structural responses that, at a minimum, require a comprehensive understanding of all modes of tunnel deformation due to both P- and S-waves. The majority of studies in this field have focused on a single S-wave mode, ovaling or racking (where the waves impinge on a tunnel transversely with the direction of particle movement perpendicular to the tunnel axis). Significantly less work has been devoted to the other modes. This study introduces two sets of new analytical solutions, using the soil-structure interaction approach, to predict the P-wave modes of tunnel deformation: axial compression-extension and transverse compression-extension. The solutions account for both drained and undrained loading conditions, with both no-slip and full-slip interface conditions between the tunnel lining and the ground. 2-D and 3-D numerical simulations, both static and dynamic analyses, are performed to verify the analytical solutions and determine their applicable limits. The numerical analyses also provide insights into the effects of dynamic amplification on the tunnel cross section.