Solid-fluid coupling analogous material test for subsea tunnel

The hydrophobic solid-fluid coupling analogous material that took paraffin as the cementing agent was developed. The test platform composed of high-strength PVC boards and structural steel was manufactured. The optical fiber monitoring system and metering device of water seepage were exploited. Based on these, the fluid-solid coupling model test was carried out with the engineering background of the Kiaochow Bay Subsea Tunnel. Twenty experiments under different working conditions were operated in terms of influencing factors such as the water depth, the excavation area and the overburden thickness. During the test process, water inflow and multi-information like the displacement,stress and seepage pressure of nine key points were recorded. The results show that the effect of excavation unloading is rather obvious within 15 m rock stratum right above tunnel vault, so the relevant supporting structure and monitoring measurement should be strengthened. The effective grouting reinforcement measures are appropriate for submarine segment of the tunnel. Tunnel line with lesser water depth is beneficial to stability of surrounding rock suffered high seepage pressure. In order to decrease excavation area, designers ought to increase tunnel space utilization as much as possible.