Time-dependent strength behaviors of pre-grouted zones in Han river-crossing tunnel

Abstract

Grouting technology is used in subsea and river-crossing tunnels for various purposes such as waterproofing, pre-reinforcement and corrosion protection. Cement is a general grouting material that has strong time-dependent behaviors. A method to characterize the time-dependent behaviors of pre-grouted zones around a river-crossing tunnel using elastic waves is suggested, and a method for the analysis of time-dependent effects on river-crossing tunnels based on numerical simulation is proposed. First, an experimental analysis was performed to characterize the time-dependent behaviors of the grouted material. Then, the obtained results from laboratory tests were applied to the numerical simulation of a tunnel taking into account its construction sequences. From the result, it can be concluded that the stiffness and strength of pre-grouted zones with 2-7 days are appropriate to model the time-dependent behaviors of a river-crossing tunnel. Finally, the suggested analytical method of combining experimental and numerical simulations that consider the time-dependent effects on the pre-grouted zone on the tunnel behaviors can provide reliable and practical design and analysis for a river-crossing tunnel.