Field Test Study on the Compaction Effect of Waterstops for Long-section and Large-tonnage Urban Utility Tunnels

In order to further improve the waterproof performance of urban utility tunnels, two water stop test schemes were proposed on the premise of ensuring that the boundary conditions conform to the actual project, and the field test study on the compaction effect of waterstop for long-section, full-scale and large-tonnage urban utility tunnel were carried out based on the actual project. The results show that when the tunnel is fully compacted, the tension of the steel strand in test scheme 1 (static splicing + Class I waterstop) is about 90.5% higher than that in test scheme 2 (suspended splicing + Class II waterstop), which has higher requirements for the steel strand tension system; the average width deviation of the tunnel crown and bottom joint in test scheme 2 is only 0.73 mm, which is much smaller than that in test scheme 1, thus contributing to the uniform distribution of the interfacial stress of the waterstop; and the effective interfacial stresses in test scheme 1 and test scheme 2 finally reach 1.61 MPa and 1.56 MPa respectively, and the average joint widths are 7.80 mm and 4.41 mm respectively. It is recommended that test scheme 2 be adopted in the waterproof construction for this utility tunnel project.