Delivering stability and support
The primary lining phase delivers the stability of the tunnel structure providing immediate support of the excavated ground. This temporary supporting lining is commonly made of steel fibre reinforced shotcrete. When required, this phase also features the installation of reinforcement elements consisting of steel arched sections that have the shape of the tunnel contour.
Reducing costs and increasing productivity with the B.Zero Tondo™
Our patented B.Zero Tondo™ Tunnel Support System is a new solution in tunnelling and provides extremely efficient first stage support. B.Zero.Tondo™ are unique tubular steel-arch ribs, filled with pumped concrete in-situ and offering greater structural efficiency than traditional steel-arch supports. Therefore fewer B.Zero Tondo™ arches are needed, reducing costs and increasing tunnel productivity.
Maccaferri Wirand® steel fibre reinforced shotcrete (including the additives Rocksil or Apral as required) is then applied as a primary lining, limiting initial deformation of the gallery.