Ovaling deformations of circular tunnels under seismic loading, an update on seismic design and analysis of underground structures

Two analytical solutions for estimating the ovaling deformation and forces in circular tunnels due to soil-structure interaction under seismic loading are widely used in engineering practice. This paper addresses an unresolved issue related to discrepancy between the two solutions. A comparison of the two solutions shows that the calculated forces and displacements are identical for the condition of full-slip between the tunnel lining and ground. However, the calculated lining thrusts differ by an order of magnitude when assuming no-slip between the tunnel lining and the ground. The analytical solutions are compared to numerical analyses of the no-slip condition using the finite element method to validate which of the two solutions provide the correct solution. Numerical analysis results agree with one of the analytical solution that provides a higher estimate of the thrust on the tunnel lining, thus highlighting the limitation of the other analytical solution.