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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.

This work was performed to investigate the waterproofing and mechanical behavior of sealing gaskets for circumferential joints in Tianjin metro line Z2 tunnel by a full-scale experiment. A newly developed device was introduced in detail, with test procedures, essential treatment methods, and the adopted specimens for gaskets and reinforced concrete segments. Four types of EPDM and composite cross-section gasket profiles were tested under different combinations of joint openings and offsets. The gasket mechanical performance was examined through the load versus deformation relationship, while the water pressure versus joint opening relationship was applied for identifying the gasket sealant performance. The effect of gasket opening area was then discussed, based on a comparison of the test results from two similar gasket profiles. The ratio of waterproof capacity to average contact pressure was proposed to analyze the correlation between the gasket mechanical and sealant behavior. The results showed that both of the joint opening and offset had a great influence on the gasket waterproof behavior, which generally exhibited a reduction with larger joint opening and offset. A relatively small change in gasket opening area may lead to a greater degree of variation in the gasket mechanical and waterproof performance. The leakage failure analysis indicated that bolt holes, circumferential joints and concrete cracks were the common leakage points during the tunneling construction and operation. The full-scale experimental methodology in this paper had the potential in detecting detailed leakage process of gaskets.