Design and Construction Aspects of Pneumatically Applied Concrete Final Tunnel Linings.

Synopsis:

The East Side Access Project (ESA) involves the construction of geometrically complex underground structures including a large number of caverns and bifurcations. Initially conceived as dual lined structures with either traditional concrete or shotcrete final linings (SFL), construction economy, advances in concrete placement technology and scheduling among others led to a wide use of what is referred to as freeform or pneumatically applied concrete (PAC) for the construction of tunnel final linings. PAC is a method of applying concrete without using formwork, where a wet mix concrete is pneumatically installed to encase reinforcement to full lining thickness. PAC has been widely adopted at ESA well beyond initial expectations. The paper addresses the design and construction aspects of the PAC method and contrasts it to traditional SFL lining placement. The experience made provides guidance for future PAC and SFL applications.

2016 World Tunnel Congress and 42nd ITA General Assembly Proceedings
April 22-28, 2016, San Francisco, CA (Gall, V., Thompson, A., Valdivia, A., Cao, W., Cicileo, C., & Schabib, J.)
Copyright holds the International Tunnelling and Underground Space Association (ITA).