Abstract
► Work was conducted to provide an understanding of the leakage behavior of tunnel linings. ► Concrete around the gasket, cracked zones, gasket–groove interface are places for leakage. ► Leakage of concrete segment with open base gaskets occurred at the gasket–groove interface. ► Damage to the side of the gasket groove reduces the gasket confinement and led to leakage. ► Longitudinal joint sealant capacity was improved by cycling.
This work was conducted to provide an understanding of the leakage behavior of gasketed segmental tunnel linings subjected to static ground loads and earthquake shaking of the recommended design of the Los Angeles (LA) Metro. The proposed lining was made of bolted and double gasketed precast concrete segment lining with convex to convex longitudinal joint surfaces. Lining evaluation included the sealant performance of different gasket materials under water pressure less than 90psi (Neoprene and EPDM gaskets with open base. Testing program was designed to evaluate the longitudinal joint and T-joint sealant behavior under static and dynamic loading using large scale concrete segments. The results showed that concrete around the gasket groove, cracked zones, gasket–gasket groove interface, and bolting pockets are the places of leakage in concrete segments. Besides that, damage to the side of the gasket groove reduced the gasket confinement and led to leakage. Also, the results showed that longitudinal joint sealant capacity was improved by cycling as a result of the increase in bonding between the gasket and gasket groove.