NorSand constitutive model stopped working for multi stage model after FLAC3D 7.00.148 update

It appears that the Norsand constitutive model coding has changes and no longer functions for multi-zone models.

I have modeled the staged construction of a TSF using a plane strain approximation and Norsand successfully in FLAC3D version 7.00.147. The results showed realistic and expected stress paths in p:q:e spaces.

However, when I re-analyse the same model, without any changes in the coding or FISH functions, the model does not converge and stresses and displacements reach infinity resulting in the error “An accumulated value has become greater than the maximum allowed…” This was tested in versions 7.00.148 and 7.00.151, and the error occurs in both. When using the Mohr-Coulomb, or P2PSand constitutive models on the same mesh the same error does not occur.

Curiously, simulated triaxial test calibrations using Norsand, like the examples in the documentation, appear to solve without issue.

In the Software Update Revisions, the changes in version 7.00.148 note a “NorSand model update”. However, the support documentation has not been updated to note any changes.

Has anyone been able to find the changes to the Norsand model or how this error can be prevented? It appears I will need to roll back my version to before the update to the Norsand model.

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Hi Paul. could you please send the datafile to Itasca (flac3dsupport@itascacg.com) so that we could duplicate the issue and then have an investigation and possible fix?

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Will do. Look forward to your input!