Waterproof performance of tunnel segmental joints under different deformation conditions

Abstract

Segmental joints are prone to take place adverse deformation of opening, dislocation and rotation. Thus, they are recognized as vulnerable parts for shield tunnel waterproof performance, however, very little light has been shed on this subject. In this study, a series of experimental and numerical analyses are presented to investigate the effects of various joint deformation conditions on the tunnel waterproof performance. Firstly, specially designed tests are conducted to investigate the waterproof performance of segmental joints under different joint opening, dislocation and rotation conditions. Then, a novel method for simulating the joint leakage process is proposed and validated by comparisons with experimental results. Considering different potential leakage paths at sealing gaskets, the changing rule of waterproof capacity and leakage mode with joint deformation is thoroughly investigated. Finally, the sealant mechanism of sealing gaskets is revealed and the relationship between joint deformation and joint waterproof capacity is established to obtain the measures to control the leakage of segmental joint. The results indicate that: (1) the joint waterproof performance is significantly affected by three typical joint deformation conditions of opening, dislocation and rotation, (2) the proposed simulation method for joint leakage process is proved to be reliable by experimental results, and can be further adopted to predict the leakage behaviour of the joint, and (3) the joint water leakage can be controlled by restricting the joint deformation and optimizing sealing gasket structure.