Abstract: The traditional formwork of the prefabricated utility tunnel has sever issues, including expansion of concrete, instability of the support system, and low efficiency of formwork clamping and removal. In this paper, an integrated hydraulic formwork is designed and developed for a longsection and largetonnage prefabricated utility tunnel demonstration project in the Xiong′an New Area. Based on the analysis of the characteristics and construction process of an integrated prefabricated utility tunnel, a detailed design of the hydraulic formwork is conducted from the aspects of the side formwork, end formwork, inner formwork, and drive mechanisms. To avoid scratches on the tunnel during formwork removal, the side formwork uses hydraulic drive mechanisms. To balance the force on the formwork body, the end formwork uses linear drive mechanisms. To improve the efficiency of formwork assembly and disassembly, the internal formwork uses a selfpropelled device and a guiding mechanism. Further, the antibulging and posture maintaining devices can ensure the forming quality of the prefabricated utility tunnel. Finally, the prefabricated hydraulic formwork is subjected to a field test and an efficiency analysis. The practical results show that hydraulic formwork can significantly improve the quality and efficiency of prefabrication of longsection and largetonnage prefabricated utility tunnels.

Key words: prefabricated utility tunnel, hydraulic formwork; structural design, drive mechanism, efficiency analysis