Analyses of Seepage Problems in a Subsea Tunnel Considering Effects of Grouting and Lining Structure

Analytical solutions for water inflow and water pressure based on steady-state water inflow into a circular subsea tunnel in a semi-infinite aquifer are deduced depending on the rock permeability, drainage at the lining, and grouting parameters. Based on the parameters of the Qingdao Jiaozhou Bay subsea tunnel, the differences between the proposed solutions and three previous methods are analyzed. Comparisons of the results of different methods verify the validity of the proposed analytical solutions and manifest the superiorities of the proposed solutions in reflecting the effects of grouting and lining structure on the seepage problems in a subsea tunnel. Discussion of the lining structure is also made and we conclude that block-based and limited drainage should be the design principle of lining structures. Finally, the method of identifying the most rational and economical grouting parameters is presented.