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. 

Bilder sammen

 
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.

Figur1

 

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

 

Figur2