Field tests on effects of changes of tidal level on stress of large-diameter shield segments under rivers

Relying on the slurry shield tunnel project of Wangjiang Road in Hangzhou, the tidal change characteristics of the water level of the Qiantang River are analyzed, the earth pressures, pore water pressures and segment internal forces of the segment linings at the section 375 of the right line are monitored by embedding test elements. The studies shown that the formation can only be stabilized if the distance from the monitoring ring to the excavation face is more than 18 rings. There is a positive correlation between the water level and the external water pressure of the linings, and the tide-induced change in water pressure is reduced by 45% to 77% after passing through the stratum to the tunnel segment compared with the calculated values. The change of tideal level has small effects on the safety factor of the segment structures.