Abstract: The design, construction, and high-precision segment fabrication of shield tunnel socket segment structures present significant challenges. The authors investigate the mechanical properties of a novel socket joint structure, the segment joint waterproofing system, the segment fabrication tolerance design method, and control standards, as well as segment construction control technology. A research approach combining numerical simulations with model tests is adopted. Key technologies for the innovative joint design of shield segments are summarized, resulting in the development and application of circumferential and longitudinal socket joints in the construction of the second channel of the Nanjing Jiangxinzhou sewage collection system. The following innovative achievements are highlighted: (1) High-performance longitudinal joints and high-toughness circumferential joints are developed. An innovative joint structure design method involving sockets and inserts is proposed, leading to the establishment of a novel technical system for both circumferential and longitudinal joints. (2) Joint deformation control standards for socket segments are introduced, and a low-compression, low-friction, and high-tensile ethylene-propylene-diene monomer rubber sealing technology is developed to address the waterproofing challenges posed by the novel socket-type joints. (3) Tolerance design methods and control standards for joint components are proposed. Furthermore, a high-precision control technology for segment prefabrication and assembly is established, enabling high-precision construction of the novel socket shield tunnel segments.

Key words: shield tunnel, underwater tunnel, socket joints, performance under stress, joint waterproofing