7.93 m Open TBM Shotcrete System Improvement and Innovation – Jilin Project, China
In May 2018, a 7.93 m diameter open gripper (Main Beam) TBM completed the 24.3 km long Jilin Lot 3 tunnel under a maximum overburden of 272.9 m. The tunneling operation for the water transfer project, located in northeastern China, achieved a national record of 1,423.5 m in one month despite challenging conditions. This paper presents an improved, innovative shotcrete system for TBM preliminary lining, developed through experience on previous projects. The shotcrete system, along with other structural design elements and a properly developed ground support program, allowed the TBM to bore successfully in variable hard rock and fault zones. The paper discusses how the shotcrete system and structural design increased safety and improved performance in a cost-effective manner. It defines the variables that allowed the TBM to advance at rapid rates and makes recommendations for future types of projects that could benefit from the shotcrete system.
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