Abstract
Against the backdrop of integrated development of urban rail transit and various types of railways in China, the application of single-tube double-track shield tunnels is increasing. Compared with traditional double-tube double-track tunnels, they have larger diameters and more complex internal structures, require the installation of middle partition walls, and their construction techniques differ significantly from those of single-track tunnels: it is necessary to organize the prefabrication, installation, and cast-in-place construction of multiple structural components such as portal frames, middle partition walls, and curved segments within the limited cross-section, and to conduct specialized optimization for the transportation, positioning, and joint connection of large prefabricated components. This paper selects several typical single-tube double-track shield tunnel projects in China, expounds on the conventional procedures for internal structure construction of single-tube double-track tunnels, and summarizes the design and construction techniques of the internal structures for each project, conducting a comparative analysis from aspects such as construction efficiency, structural segmentation, degree of internal prefabrication, and tunnel length, providing reference for engineering technical solutions for similar construction projects in the future.
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Preamble
Construction Technology of Internal Structures in Single-Tube Double-Track Shield Tunnels for Urban Rail Transit
Wang Yichen¹
¹Shanghai Tunnel Engineering Co., Ltd., Shanghai 200000, China
Abstract
Against the backdrop of integrated development between urban rail transit and various railway systems in China, the application of single-tube double-track shield tunnels is increasingly growing. Compared with conventional double-tube double-track tunnels, these structures feature larger diameters and more complex internal configurations, requiring the installation of a central partition wall. Their construction techniques also differ significantly from those of single-track tunnels, as it is necessary to coordinate the prefabrication, installation, and cast-in-place construction of multiple structural components—including rectangular segments, central partition walls, and curved segments—within a limited cross-section, while implementing specialized optimizations for the transportation, positioning, and joint connections of large prefabricated components. This paper selects several typical single-tube double-track shield tunnel projects in China to elaborate on the conventional construction procedures for internal structures, summarizes the design and construction techniques employed in each project, and presents a comparative analysis from the perspectives of construction efficiency, structural segmentation, degree of internal prefabrication, tunnel length, and other factors, thereby providing valuable references and insights for engineering solutions in future similar projects.
Keywords: rail transit; regional railway; single-tube double-track; tunnel internal structure