Triangluar zones do not work with PM4Silt2d

Hi all

Please take note of a bug with the implementation of the PM4Silt model - it only works for quadrilateral zones, not triangular zones.

A workaround is to make each encountered triangular zone elastic with secant modulus compatible with neighboring PM4Silt zones using “if zone.code(zp) == 1 then…”

Hopefully an update is pending!


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Hi Paul, thank for reporting this bug, we can forward your request to the developer of this model, or you may like to contact them directly (PM4Silt | US Minneapolis - Itasca Consulting Group, Inc. ).

Hi Paul. We became aware of this issue in the early Fall and fixed it in the latest dll version found here PM4Silt Files | PM4Silt
Are you using the dll compiled 10/9/2023? If no, then please update to that and let me know how things work out. If yes, then we need to see what you are dealing with and probably fix something more.

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Hi Katerina! Thanks for the response. I thought that I had updated the dll’s but seems I haven’t. I’m testing out the new ones now and will let you know.

[Edit: It works! I’m still having issues converting the model in static equilibrium from norsand to pm4silt with neighboring zones of mohr-coulomb and interface elements without it failing. Are you aware of any reason that pm4 will not play nicely with interfaces? The current workaround is to prevent pm4silt zones from contacting the interface but it is not ideal. I’m cleaning up a model that I can send for you to have a look at.]

Looking forward to the one-day course on the PM4 models later this month!

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Sorry I missed one part of this question. I am not aware of particular interface issues. What do you define as failing? We have for example used it with retaining wall interface elements (albeit that was in FLAC8.1). On another note, we have released a routine to connect pm4 models to free field conditions. Not directly relevant but still useful :slight_smile:

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Thanks Katerina!

The interface issues I’ve been having seem to stem from attempting to switch from NorSand to PM4Silt. After the course you presented, I’m much more confident using PM4 with static analyses so starting off with PM4Silt seems to present no issue on the interfaces. Yay!

Thanks for letting me know! the free-field routine is VERY useful for me right now! I was just using elastic zones on the edge but it was a bit of a pain.

Awesome on ALL fronts. :partying_face: :tada: