I am modelling a deep excavation that uses Diaphragm walls as ERSS and cross walls the lateral support system in Plaxis 2D. I have used plate elements to model Diaphragm walls and used linear elastic material (G30 concrete properties) to model the smeared cross wall.
After running the analysis, the deformed mesh at the final stage of excavation shows that the cross wall is cutting through the Dwall and jutting out into the outside soil as circled in red in the image attached. The effect is more pronounced when I model the same system in Plaxis 3D (I hid the soil elements for clear visibility of the problem area)
Is this a common phenomenon due to the exaggerated scale of deflections in deformed mesh view and means nothing? Or does it actually mean the cross walls are cutting through the Dwalls which means some error in my modelling - if so, how to model it correctly?
I have attached my model in this link in case you need to check - https://drive.google.com/file/d/17Ts7qAjRknKLLnJ3JgvmeDn6HOGd4cUv/view?usp=sharing
Thanks a lot in advance,
The deformed mesh is a scaled plot that shows the way the elements deform at a specific phase (or step). You can always change to a different scale using the Scale option.
To ensure everything is okay, you can check the deformations of the soil (interface) and the plate at that area.
Keep in mind that the use of interfaces for soil-structure interaction allows for a relative movement between the soil and structure. This means that by directly assigning a material to the interface which has very low stiffness you can develop large deformations in the wall.
Therefore, I would recommend checking the properties assigned to the interface, such as the stiffness used and the addition of Rinter (reduction factor).
You can also read the following article for more details on modelling the soi-structure interaction:https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/45944/modelling-soil-structure-interaction-interfaces
If you still have questions, submit a service request.
Then, one of our support engineers can help you in detail: https://apps.bentley.com/srmanager/ProductSupport