Effect of Seismic P-Waves Propagation on Circular Tunnels in Layered Ground

Abstract

During propagation of the compression seismic P-waves, the tunnels are subjected to ovaling deformations. In cases where the soil stiffness is varying along the tunnel cross-section, tunnel lining may take sharper deformed shapes and subjected to magnified bending moments and thrust forces. This paper investigates the effect of the soil stratification on the seismic behavior of circular tunnels under P-waves loading. A 2D finite element models with time history earthquake (EQ) analysis were performed accounting for different tunnel/soil interface slippage conditions. The finite element analysis results were compared with recent analytical solution for calculating the seismic forces of the tunnel lining. The study proved that soil stratification has a great effect on the tunnel seismic forces and it should be considered in the analysis and design. Illustrative curves were presented in this paper to give approximate magnification factors for the anticipated forces. It should be used as a guide in the preliminary design stage.

Analytical model for a circular lined tunnel embedded in the layered soil under seismic waves

“…Zou et al 24 proposed a semi-analytical method to estimate the response of a circular tunnel with imperfect interface bonding in the layered ground under oblique body waves. Amr et al 25 used the finite element method to investigate the wave scattering by a circular tunnel in the layered soil under incident P waves.…”