Critical Slip Surface -outside of specified boundary when using Optimized Slip Surface

AqueelHafeez
AqueelHafeez Unconfirmed Posts: 1 New Member
in GeoStudio

Hi everyone.

I am currently undertaking a slope stability assessment using SLOPE/W and have encountered an issue with the optimized slip surface search.

The analysis has been configured with specified entry and exit regions; however, the reported critical slip surface appears to extend outside the defined search bounds. Based on my understanding, the entry and exit regions should constrain the potential slip surface locations, so I am uncertain why the critical surface is being identified beyond these limits.

Could you please advise:

  • Under what circumstances the critical slip surface may extend outside the specified entry and exit regions?
  • Whether this behaviour is expected within the optimization/search algorithm.
  • If there are any model settings, optimization options, or search parameters that could cause this outcome.
  • Whether additional constraints are required to ensure the critical slip surface remains within the nominated search boundaries.

I have attached the relevant model screenshots illustrating the issue.

image.png image.png

Answers

  • PrachiChitkara
    PrachiChitkara Posts: 446 admin

    Thanks for sharing such a detailed question, @AqueelHafeez

    Tagging a few community members who may have come across similar behaviour or have experience with SLOPE/W optimization searches: @shiWalter @SubhasishPasupalak1 @JigneshBPatel @SamHarris

    If any of you have insights into why the optimized slip surface might extend beyond the specified entry/exit regions - or any best practices around the search settings - we'd really appreciate your thoughts. Thanks in advance!

  • shiWalter
    shiWalter Posts: 9 Calcite Rank Badge

    Thank you for your invitation.

    I have encountered a similar issue when using SLOPE/W in the past. As you may know, the optimization algorithm does not have constraints based on the entry-exit zone. As a result, the optimization may find a more critical slip surface further up‑slope, which can extend beyond the defined bounds. In such cases, I would suggest that optimization may not be appropriate.

    However, in most practical scenarios, it is relatively uncommon for the critical slip surface to extend outside the entry‑exit limits. I would recommend combining other automatic search methods with optimization algorithms for a more comprehensive analysis. Alternatively, you can consider disabling the optimization option altogether.

    Currently, SLOPE/W does not support setting two separate groups of slip surface limits simultaneously. It is possible that this feature may be supported in future releases.

    I hope this helps. Please let me know if you have any further questions.

    Best regards,

    Walter.

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