Composite Macro-synthetic Fiber and Steel Reinforced Shotcrete for Final Lining

Accelerated and cost effective construction methodologies for tunnel lining have attracted a growing attention in recent years. Sequential construction such as excavation, primary support, reinforcement, formwork, concreting and contact grouting has made limitations for decreasing the execution time. Available methodologies to accelerate the tunnel construction will require the elimination or merging of some of these steps. An innovative construction technology has been presented in this paper which reduces the reinforcements, omits the formwork and contact grouting and reduce the construction volumes by utilizing the appropriate properties of macro synthetic fibers, steel reinforcement and wet shotcrete. The design can also utilize the bearing capacities of primary support and create a composite single shell for load carrying. The procedure for analysis, design and construction of the support has been discussed in the paper. All materials including special distributed latticed panels, steels and fiber shotcrete were selected so as to satisfy the durability criteria. The lining can be used for different applications including metro tunnels, road tunnels and sewerage and waterways.