ABSTRACT
Thames Tideway West Project involves the construction of 7No deep shafts, one 7km Main Tunnel and 4No. connecting Tunnels through London Strata. Of particular interest are the Shafts, which are designed as composite linings with Steel Fibre Reinforced (SFR) Sprayed Concrete Lining (SCL) as Primary Lining and Cast In Place (CIP) SFR Concrete as Secondary Lining. Emphasis is given to the design and construction of the largest SCL shaft of the West contract (also the largest SCL Shaft ever constructed in the UK), at Carnwath Road Riverside (up to 25m ID, 50m in depth), from which the Launching of the Tunnel Boring Machine (TBM). The design philosophy required the development of a special SFR SCL mix with enhanced water resisting capacity to enable the omission of waterproofing membrane from the works. This Paper discusses the design philosophy, the extensive SCL trials, the construction challenges and the monitoring results thus far.
