Itasca Consultants AB (Sweden) has conducted regional-scale stress modeling of the Stockholm area, as part of the design work for new metro lines. The expansion of the new metro in Stockholm includes several extensions, of which one new line in the south will pass through a number of regional large-scale structures. The magnitude and orientation of the stresses close to structures are uncertain and stress measurements are not practically possible. To increase the understanding of the rock stress situation in the southern side of Stockholm and to quantify stress conditions near these structures, a numerical stress analysis was performed. The analysis was carried out using 3DEC, in which topography and known structures were included explicitly. The model included eleven minor structures assumed to be vertical and two major structures dipping 70°. The results showed that stress re-distributions occur for a distance up to 50 m from the structures where, for example, higher or lower stress magnitudes are to be expected depending on side of the structures (hangingwall or footwall side). This work was presented at the Swedish Rock Mechanics Day ("Bergmekanikdagen") in Stockholm (March 13, 2017).

Plan view of the Stockholm area and model limits as purple boxes, structures included in green and red

Numerical model in 3DEC, perspective view to the left and cut A-A to the upper right and a zoomed-in area to the bottom left

Itasca Consultores S.L. has been modeling the transient flow through the joints of a granitic rockmass. The objective is the estimation of the inflow towards the connection gallery between two railway tunnels (160 m depth), and of the radial distribution of fluid pressure acting on the impervious lining of the main tunnels.

Figure 1. Pattern of blocks around the gallery

Figure 2. Boundary flow condition around the gallery

Transient flow has been simulated afterwards; Figure 3 and Figure 4 show the fluid pressure after 1 and 24 hrs of flow simulation.

Figure 3. Joint fluid pressure after 1 hr.

The fluid pressure acting on the tunnel lining was extracted from the model at different distances from the junction (Figure 5), as well as the evolution of the inflow towards the gallery, that is presented in the graph of Figure 6, together with the steady-flow estimation derived from the Goodman’s formulae.

• FLAC3D 6.0 is released on April 3rd:
  FLAC3D beta-release version 6.0 is available for download on the following page: http://www.itascacg.com/software-demo.
  
  
• PFC 6.0 will be released in less than one month. You are invited to prepurchase the next version. Any PFC 4.0 user who upgrades his license to PFC 5.0 will receive Version 6.0 free of charge if ordered before the beginning of the pre-released period.
  
  
• Subscribe to the Itasca Youtube channel to be informed of the latest updates: webinars, tutorials, examples made with our software, etc. :
  https://www.youtube.com/user/itascacg/playlists).
  
  
• Free technical support for all the licenses of FLAC version 7.0 expires on April 21st, 2017. Per our technical support policy, Itasca continues to provide free technical support for software versions for one year from the date they are superseded by the release of a new major version.
  

Current Updates:

Itasca will host introductory training courses in Europe:

Please visit www.itascacg.com/training for full details.

For users who envisage the need for substantial amounts of assistance, consulting support or customized training course are available.
Accordingly, users are encouraged to submit sample problems prior to the training session for our review and preparation. These problems would then be used as practical applications of the code during the training sessions.

Slope Stability 2018
Jonny Sjöberg appointed Keynote Speaker