North Downs Tunnel, Channel Tunnel Rail Link: secondary lining

摘要

Site-batching proved to be a wise decision, affording tighter control and improved availability. Close contact between the technical and production teams enabled the materials to work. The choice of pfa proved beneficial in terms of heat reduction and concrete cohesive-ness. Other benefits were obtained from using recycled water and hot water when conditions dictated. The result was a secondary lining concrete that gained good early strengths so the cycle time was always achieved with no loss of pour due to lack of striking strength. These were all major contributions towards the achievement of production rates and project completion ahead of programme (see Figure 5).