3D Scanning Speeds Tunnel Surveying
Facing constant interruptions from truck traffic through Norway’s Maursund and Kagen tunnels during renovations, surveyor Sylvia De Vuyst decided against using the typical total station for such projects and instead opted for a 3D scanning total station. As a result, De Vuyst is able to work at six times the speed of multiple-person crews, as construction work continues.
When professional surveyor Sylvia De Vuyst arrived in the northern edges of Norway in March 2021 for a significant tunnelling project, she wasn’t sure what to expect. Freshly hired as the tunnel surveying manager for Mesta, a civil engineering construction company based in Lysaker, Norway, De Vuyst would be the lone surveyor responsible for the NOK $211 million (US $24.8 million) renovation of the Maursund and Kågen Tunnels, two critical passageways that connect the cities of Nordreisa on the mainland and Skjervøy on Kågen island.
Each about 2 kilometers long, the Maursund Tunnel (Maursund) travels under the North Sea, reaching a depth of −92.5 meters (−303 ft) below sea level and a 10-percent grade in some areas; the Kågen passes through Kågen mountain, which is vulnerable to avalanches and landslides. Built in 1991, both structures will undergo extensive upgrades including widening their carriageways, installing new LED lighting, Co / No2 gas meters, new water and frost protection, and new drainage systems, and building new road surfaces.
After one week in the dark, damp tunnels, one project requirement became abundantly clear to De Vuyst: she’d need to be agile.“A major challenge with the Maursund is that it needs to stay open 24/7 to allow traffic to pass through at set times,” says De Vuyst.
“This means that many times a day the diggers and bolt riggers need to move to the side, big trucks need to drive out and sometimes I need to stop my survey work. So when we’re clear to work, we have to maximize our productivity. To ensure construction stays on target and pace, I need to be efficient, reliable and precise.”