Laboratory tests on mechanical characteristics of fully and partially wrapped waterproof systems for tunnel lining

Arguments and focus have always been given to the evaluation of the fully and partially wrapped waterproof systems for tunnel linings. Based on Xiangan subsea tunnel project in Xiamen, similarity model tests are performed to explore the distribution of water pressures under various drainage conditions (fully undrained, partially drained and drained). The model test scale is 1:38.88. The water pressure and soil pressure are applicable at the mean time during the tests. The test results show that the fully and partially wrapped waterproof systems are similar under undrained condition, while the partially wrapped waterproof system can effectively reduce the water pressure against the tunnel linings, and it is more friendly to the structure under the drained condition. In addition, the area of the partially wrapped waterproof system is smaller than that of fully wrapped waterproof system. Therefore, the partially wrapped waterproof system is recommended.