Adaptability of polyurethane/water glass grouting reinforcement to subsea tunnels

Abstract Polyurethane/water glass (PU/WG) is an organic–inorganic hybrid grouting material used in underground engineering. However, its adaptability to subsea tunnels remains poorly investigated. In this study, curing time, hardening time, seawater influence, strength growth, and cyclic loading tests of PU/WG as well as scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy characterizations were performed. The typical curing and hardening times of PU/WG were 2.02 and 2.49 min, respectively. The strength of the material developed fully when the sample was aged for 2 h. The peak strength and strain were respectively reduced up to 10.9% and 19.6% at the most owing to seawater corrosion. The minimum strength and minimum strain were of 37.7 MPa and 26.9%, respectively. The cyclic loading test results confirmed the high fatigue resistance of the PU/WG material. PU/WG is an ideal reinforcement grouting material for subsea tunnels.