THE FUTURE OF SPRAYED CONCRETE TUNNEL LININGS

Abstract

Developments in the use of sprayed concrete for tunnel linings are described. Constitutive models used to describe the behaviour of sprayed concrete are outlined. The use of sprayed concrete for permanent linings in rock tunnels and for secondary linings is described. Concerns relating to the effects of potentially high early-age loads on primary sprayed concrete are discussed. Durability is directly affected by the choice of constitutive models in design. The equipment used for sprayed concrete linings is considered. Semi-robotic spraying is now common. The use of ready-mixed concrete in the wet process and automatic dosage of admixtures has improved the final product consistency.