Three new underground stations will be established along the route. The total cost of the project is estimated at SEK 20 billion. NGI is a sub-consultant to a consulting group consisting of Tyrens, Sweco and Bergab for rock mechanics before station Korsvägen. 

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Korsvägen station will have an extensive tunnel system with two parts of the station in rock and a middle part in loose masses. Both the western and eastern parts of the station will have cross-sections that are up to 50 m wide and with a rock cover of around 15-25 m.

This requires a solution with a series of concrete piles in the center line of the station, something that has never been built before. In addition, a cross hall (intermediate level) with a span of 28 m will be made, where the rock cover is at least 7-8 m.



The solution with concrete piles requires cooperation calculations, mainly carried out as continuum calculations in 2D and 3D with Plaxis. As the material is a fractured rock mass (gneiss), the "Jointed Rock Model" has been used, in addition to Mohr-Coulomb, to calculate realistic loads on the concrete pillars in the form of moments, normal forces, and shear forces.

The stability of the rock mass is modeled as a dis-continuum in 2D and 3D with UDEC and 3DEC.


NGI has two main tasks in the project

  • Advanced numerical analysis

  • Rock engineering expertise