Sprayed Waterproofing Membranes on recent SCL Tunnelling Projects in London
The London tunnelling sector has been very active in recent years with many tunnels constructed using Sprayed Concrete Linings (SCL), often incorporating a sprayed waterproofing system between the primary and secondary linings. This paper discusses the use of a sprayed waterproofing membrane in tunnels constructed using the SCL method at the Bond Street Station Upgrade and Crossrail C510 projects. A particular focus is given to the learning process at both projects and how both projects ensured the sprayed waterproofing membrane achieved a high quality. This paper also explains the chemistry of the sprayed waterproofing membrane and provides recommendations for successful and efficient application of this system on future projects.