Effect of water leakage in tunnel lining on structural performance of lining in subsea tunnels

This paper presents the results of an investigation into the effect of lining leakage on the structural performance of lining in subsea tunnels. A parametric study on a number of hypothetical subsea tunnels was conducted within the framework of two-dimensional stress–pore pressure coupled finite element analysis with due consideration of tunnel cover depth, depth of water to seabed, and ground type. The results indicate that the lining leakage increases axial thrust as well as bending moment, with more pronounced increases in bending moment. Also shown is that there exists an increasing trend of leakage induced lining forces with an increase in the water depth above the seabed but with no significant influence from the cover depth. It is also shown that the progressive development of leakage induced lining forces can be best fitted with an exponential function which can be used to predict the lining force increase for a given tunnel condition. Practical implications of the findings are discussed.