Customer story: Reducing risk along tunnel corridors in planning phase

Nye Veier received assistance from Emerald Geomodelling before designing and building tunnels for the new rv.4 highway along the west-coast of Norway’s largest lake Mjøsa.

The new 20-kilometer road between Gjøvik and Mjøsbrua will improve living and working conditions in the area by reducing travel time and enhancing traffic safety. The current road has a 70 % higher rate of serious accidents including head-on collisions and is thus prioritized for development. Nye Veier is responsible for the project and Norconsult is the consulting engineer for the planning assignment. The planning work started in 2025. A key geotechnical challenge for the project is to identify the ideal placement of a tunnel under the regional city of Gjøvik where only very limited ground investigation data is available in the early phase of the project.

The EMerald Geomodelling team was brought into the project in close partnership with SkyTEM Surveys of Denmark following a joint development project resulting in a new generation geoscanner, perfectly suited for the semi-urban environment of the tunnel planning project

For the first time in Norway a new-generation high-resolution Geoscanning sensor, the SkyTEM Diamond system was deployed using a small helicopter able to fly slow and low in areas close to and surrounded by dense population. Three critical areas for the planned tunnels, totalling 2.7 square kilometres, were covered in three days of flying.

While geophysical data were processed by specialists at SkyTEM, the EMerald team prepared the sparse geotechnical data for integration through the EMerald Geomodelling™ ML workflows. To enable efficient planning work, initial ground models were presented to Nye Veier’s engineers five weeks after survey completion. Final models integrated with design-critical analysis were available two months after that including a one-month summer break.

Project timeline

28th May – Geoscanning of 2.7 km2 completed in 3 days
3rd July – Initial ground models presented
July – August – Fill in drillings ongoing
26th August – Final ground models delivered

Before geoscanning, the project faced significant uncertainties in ground conditions as only very sparse datapoints from existing and newly drilled geotechnical soundings and samples were available. Choosing a sub-optimal tunnel alignments would have involved significant risks, and potential cost increases later in the project.

The integrated EMerald ground models provide full coverage and allow for data driven decisions with quantified uncertainty. Whether a tunnel is dug in soil or rock determines costs, resources and construction emissions, these risks are now considerably reduced as tunnel options can be assessed with respect to top of rock surface and existence of black shale units. Critical locations can now be identified and followed up with well-placed soundings and sampling.