Abstract:

With the largescale construction of shield tunneling projects, the water pressure faced by shield tunnels is increasing, and its waterproofing is a major limitation for the advancement of shield tunnels. Moreover, the technical reality of inapplicable standards, various waterproof design types, extensive construction technology, and frequent tunnel leakage should be improved. The waterproofing system of shield tunnels, technical standards and waterproofing system, design of the waterproof structure of the segment, and waterproofing construction technology are being considered due to the development trends in large buried depth and high water pressure of shield tunnels in China. The following are the conclusions reached: (1) The impact of the choice and design approach of the gasket section taking into account the elasticity of randomness, quantitative assessment method of the waterproof ability of the gasket, "dynamic" opening of the joint, and impact of the staggered platform on the waterproof ability are the research areas for the waterproofing mechanism of the segment joints. (2) There is an urgent need to establish new waterproof technology standards, which considers the water leakage and waterproofing measures for each waterproof level, change the waterproof concept, and should establish calculation standards for the permitted opening and spacing of the design as well as the value basis. (3) The study on waterproof techniques such as external waterproof coating, secondary lining, and injection of sealant into joints must be strengthened, and the rationality of construction should be considered when designing a waterproof structure. (4) Future waterproof construction technology will advance only with appropriate team management, training of skilled chemical industry employees, and development and adoption of novel waterproofing materials and procedures. (5) Intelligent monitoring and comprehensive prevention and control of water leakage during tunnel operation is a crucial in future.

Key words: shield tunnel, high water pressure, joint waterproof mechanism, waterproof technical standard, waterproof system, waterproof structure, waterproof construction technology