A novel test setup for determining waterproof performance of rubber gaskets used in tunnel segmental joints: Development and application

摘要

In this paper, a novel test setup was proposed to perform mechanical and waterproof tests for rubber gaskets used in tunnel segmental joints. Based on the newly developed setup, it is available to simulate typical joint deformation observed during construction and operation stages, e.g., opening, offset, rotation, and eccentric compression. The components and configurations of the setup were presented in detail. Special treatments were subsequently illustrated for ensuring water pressure loading and rational leakage mode. The setup was applied using test specimens obtained from a rapid rail transit shield tunnel under design. Four groups of gasket mechanical tests and 22 groups of gasket waterproof tests were carried out to evaluate the reliability and functionality of the setup. The load-deformation relationship was adopted to demonstrate gasket-in-groove mechanical behavior, while the factors influencing gasket waterproofness were also considered through analyzing the sealant capacity measured under different conditions. The results show that there exists a close correlation between the mechanical and waterproof performance of gaskets. Deterioration of gasket waterproofness generally occurs due to joint offset. Positive and negative joint rotation leads to the opposite variation trend of sealing performance for gaskets. The water leakage phenomenon observed in tests shows good agreement with the field survey results. The developed test setup and methodology provide novel insights into the waterproof examination of gaskets in complex situations.