Effectiveness of One-Sided Gasket Waterproofing System

The application of shield Tunnel Boring Machine (TBM) is steadily increasing in downtown areas. Since segments are used in shield TBM, gaskets are mostly required for the waterproofing system. Each of the two facing segments has a gasket attached to it, and the two gaskets are pressed tightly together. However, construction errors such as offsets and gaps may cause water leakage during the segment assembly process. In this study, a new waterproofing system was developed that ensures higher waterproofing performance while essentially eliminating the offset effect by putting a gasket on only one side rather than both sides. To investigate the effectiveness of the new system, waterproofing performance tests were conducted, and the results of the existing system were compared with those of the new system. The results of the existing system showed that, when the offset exceeded 5 mm, the gaskets rapidly became vulnerable to leakage regardless of the gap. However, the new system showed that adequate waterproofing performance could be acquired when the height of the gasket was secured above a certain level. Finally, it was found that the new system proposed in this study was relatively superior to the existing system.