Piled-Raft Modelling in PLAXIS 3D

RE: Piled-Raft Modelling in PLAXIS 3D

Edward W — Thu, 06 Apr 2023 16:38:22 GMT

Okay thanks for the reply. I want to ask further question

I have modelled my loading as the following

#1 by stage : 100 -> 200 -> 300 -> 400 (i change the surface load value every phase)

#2 load it directly to 1000

Based on these two cases, my model collapse at #1 but work perfectly fine at #2. Can you explain the reason for this? Thanks

RE: Piled-Raft Modelling in PLAXIS 3D

Dennis Waterman — Thu, 06 Apr 2023 07:14:22 GMT

Dear Edward,

In principle if all the embedded beams have fully mobilized their capacity but the raft still has capacity, the calculation should not stop because there is no failure yet. So considering that it does stop in your case, it either means that the raft has no more capacity either, or it's a numerical issue. For instance that the calculation needs to do a few unloading steps to redistribute stresses before it can continue to load the raft, and it considers the successive unloading steps as a sign of failure. This can be overcome to increase the Number of unloading steps in the Numerical control parameters of the Phase settings.
But there can be other numerical reasons as well, which would then indeed by model-specific as my colleague already suggested. In which case you would indeed have to send us a Service Request.

With kind regards,

Dennis Waterman

RE: Piled-Raft Modelling in PLAXIS 3D

Edward W — Thu, 06 Apr 2023 04:29:40 GMT

Okay. And also i try to go to SP but it says error TXH or something. Is there any other alternatives?

RE: Piled-Raft Modelling in PLAXIS 3D

Hung Ho Manh — Thu, 06 Apr 2023 04:09:43 GMT

If so, probably, the model does not fully collapse by bearing capacity but could be localized. So, we need to check the project and investigate.

RE: Piled-Raft Modelling in PLAXIS 3D

Edward W — Thu, 06 Apr 2023 04:05:49 GMT

But I saw that if you use PLAXIS 3D Foundation the model can be run. Can you tell me what makes the difference?

RE: Piled-Raft Modelling in PLAXIS 3D

Hung Ho Manh — Thu, 06 Apr 2023 03:59:38 GMT

No way to run the model if the model fully collapses due to bearing capacity because no convergence can be achieved between driving force and resistance. This is also a real physical behavior.

RE: Piled-Raft Modelling in PLAXIS 3D

Edward W — Thu, 06 Apr 2023 03:57:01 GMT

Okay, Thanks!

But I want to ask is there a way so that a model can still run even though all the embedded piles are at their full capacity?

RE: Piled-Raft Modelling in PLAXIS 3D

Hung Ho Manh — Thu, 06 Apr 2023 03:46:20 GMT

communities.bentley.com/.../plaxis-3d-tunnel-modelling

RE: Piled-Raft Modelling in PLAXIS 3D

Edward W — Thu, 06 Apr 2023 03:39:15 GMT

Sorry, but the page no longer exists :(

RE: Piled-Raft Modelling in PLAXIS 3D

Hung Ho Manh — Thu, 06 Apr 2023 03:25:23 GMT

If you do not want us to check the project, so, you need to understand why it fails first. General idea to check it is shown by our colleague here: https://communities.bentley.com/products/geotech-analysis/f/forum/243632/plaxis-3d-tunnel-modelling adjusting possible things after that.

RE: Piled-Raft Modelling in PLAXIS 3D

Edward W — Thu, 06 Apr 2023 03:14:13 GMT

No. its not related to a specific project. It's just that currently I want to model the load-settlement curve of a piled-raft but the model stopped (collapse) when all of the piles capacity are fully utilized. I want to know how can I overcome this so that I can continue to run it even though the piles are at full capacity. Thank you!

RE: Piled-Raft Modelling in PLAXIS 3D

Hung Ho Manh — Thu, 06 Apr 2023 01:20:35 GMT

Hello Edward,

With an enquiry related to a specific project, we recommend you to submit a SR using the link here: https://apps.bentley.com/srmanager/ProductSupport

RE: Piled-Raft Modelling in PLAXIS 3D

Edward W — Wed, 05 Apr 2023 16:37:32 GMT

Here is the screenshot of the model that I use