Abstract: As a critical load-bearing structure at the shield launching stage, the reaction frame system must meet the requirements for strength, rigidity, and stability to withstand the substantial thrust generated during the launching stage. Currently, in shield construction, the reaction frame support needs to be fabricated and installed on-site, often facing challenges such as high construction difficulty, low work efficiency, poor reliability, and high costs. These issues severely limit the construction progress and safety of the shield tunneling method. To circumvent these problems, this study innovatively proposes an approach that uses prefabricated reaction frame steel supports to replace traditional steel supports. This approach not only reduces the difficulty of on-site construction work, effectively controls construction risks and schedules but also significantly saves construction costs and reduces unnecessary resource waste. By increasing the usage frequency of the prefabricated reaction frame steel supports, it will highlight the great advantages of the present research method over the on-site fabrication and installation method. The application of prefabricated support systems offers a broad scope for the high-quality development of construction levels during the shield launching stage, aiming to provide guidance for the safe execution of similar projects.

Key words: Shielded Tunnel Excavation, Reaction Frame, Prefabricated Steel Support