Abstract:

Quality defects can occur in the segment assembly construction of largescale underwater shield tunnels. Herein, the authors summarize prominent studies on segment assembly for underwater shield tunnels; the studies primarily focus on quality control indices for segment assembly, the impact of assembly on the mechanical properties of tunnel linings, quality control practices, and the use of quality detection. Key topics related to the quality control indices for segment assembly, such as segment dimensions and geometric requirements, susceptibility to cracking, water tightness, and antipermeability performance, are discussed. The impact of segment assembly on the mechanical properties of underwater shield tunnel linings is summarized from three viewpoints: onsite monitoring, testing of similar models, and prototype testing. Quality control for the development and application of segment assembly equipment, sensing monitoring systems for shield tunnel segments, prediction methods for shield attitude, and segmenting positioning technologies are introduced. Moreover, the authors summarize recent research findings on segment assembly defect detection methods, including 3D laser scanning, 3D image reconstruction, and computer vision technologies for detecting cracks and leakage in segment linings. Finally, current topics and research trends in segment assembly are discussed. At present, the main challenges include the lack of effective realtime monitoring, the paucity of methods for evaluating assembly quality, inadequate research on the impact of underwater environments on the mechanical performance of segment assembly, the underdeveloped state of automation control technology, and the need for better accuracy in methods of tunnel defect detection and risk assessment. The future will bring continuous innovation and improvements in evaluation methods for segment assembly quality, automated and intelligent assembly technology, and highly precise defect quantitative analysis methods, aiming to achieve realtime monitoring, data analysis, and quantitative assessment of assembly quality and enhancing the efficiency, precision, and safety of segment assembly.

Key words: underwater shield tunnel, segment assembly quality, control index, mechanical property, quality inspection