Study on the gasket durability in the segment joint of subsurface excavated fabricated section

The aging of rubber will cause changes in the mechanical properties of materials, which in turn will cause waterproof failure.The section from the starting point of Beijing Metro Line 6 to Jin'anqiao is the first fabricated surface excavated tunnel in our country.It is of great significance to study the aging performance of the gaskets at the joints.The tunnel uses segments as the secondary lining structure, and EPDM gaskets as the waterproof material at the segment joints.In order to check whether the waterproof of the joints meets the durability requirements, an accelerated aging test was carried out on the rubber material of the gasket according to time-temperature equivalence principle, which predicts the service life of the rubber material.Due to the cumbersome calculation process of life prediction, the corresponding program was compiled to solve the problem of repeated trial calculation of parameters in the data processing.In addition, a numerical simulation of the stress of segment gaskets was carried out, and the influence of aging on the waterproof of the gasket was analyzed.It was pointed out that the designed water pressure of the gasket was increased to at least 1.75 times of the original one.