Handheld Group AB
Tunnelling Crews Excavate Underwater Roadways with Rugged Technology
This article first appeared in the Railway-News Magazine Issue 4 2023.
Contractors working on road and railway tunnel projects are using Handheld’s Algiz rugged tablets to ensure a reliable, safe and efficient excavation process that minimises downtime and reduces personnel costs.
In this example – the Norwegian Ryfast-Solbakk tunnel megaproject – crews were using Algiz tablets as part of the Amberg Navigator solution from Swiss company Amberg Technologies AG, which packages Amberg Tunnel surveying software with Handheld’s rugged tablets.
The surveying tablet solution allows tunnel workers to take precise measurements, generate tunnel profile graphics in real-time, and compile detailed reports, eliminating the need for separate surveying crews. Best of all, workers can perform these tasks on the surveying tablet with no prior surveying experience and very little computer training time.
A Tunnel beneath the Sea
Norway’s west coast is made up of hundreds of small islands and fjords – areas where seawater reaches into narrow, deep valleys with high cliffs formed by glacial erosion. People travelling to and from the coastal city of Stavanger used to rely on bridges and ferries to access areas separated by water.
The Ryfast tunnel connects Stavanger to Norway’s Ryfylke region, replacing a ferry between the two areas and cutting travel time by two-thirds. It is now the world’s longest, deepest and safest subsea roadway tunnel, spanning 14.3 kilometres and reaching 291 metres below sea level at its deepest point.
A Rugged Technology Breakthrough
To extend the tunnel through hard rock beneath the sea’s surface, workers drilled holes through the material in precise locations using enormous semi-automatic drill rigs. Explosives placed in those holes blasted the rock away and conveyor belts removed this material from the site.
Traditionally, hole placement for the ‘drill and blast’ method of tunnel construction has been determined by surveying crews, who measure tunnel profiles and use this data to mark hole patterns or geo-reference drill rigs. But using the Amberg Navigator surveying tablet with automated surveying software eliminated the need for these extra surveyors; the tunnelling crews themselves could quickly and easily perform surveying tasks with detailed real-time analysis on the Algiz rugged tablets.
