Excavation is starting on the Roberts Hill Tunnel on New South Wales’s Coffs Harbour Bypass.
Transport for NSW says preparatory work at the northern and southern portals will be completed before controlled blasting and 24-hour construction operations begin.
The work includes installing horizontal piles and steel arch frames to support the tube canopy; stabilising the top exterior of the tunnel portals with bolts and reinforced shotcrete; excavating the entrance to the tunnel portals; installing noise barriers; establishing a temporary work site; building a temporary water treatment plant; installing a ventilation system and air quality monitoring; and building site access and internal roads.
The portal preparation work will be carried out from mid-December to late February and then the team will start controlled blasting and 24-hour working.
At 160m long, Roberts Hill is the shortest of the three tunnels on the bypass.
On the 410m-long Gatelys Road, the project’s longest tunnel, heading excavation has been completed and the consortium of Ferrovial and Gamuda Australia expects to complete benching work early next year.
Transport for NSW says heading excavation is progressing well on the Shephards Lane Tunnel. It has reached about halfway on each of the 320m-long tubes, and benching work will be started and completed next year.
The Coffs Harbour Bypass, the final section of the M1 Pacific Highway upgrade, is jointly funded by the Australian and NSW governments. Each of the three tunnels will have two tubes, each designed to carry two lanes of traffic, with space for cyclists.
