Hello Abbas

You may get some hints as to how to approach the problem from our publication:

Article Investigating the performance of micropiled raft in foundati...

I can send it to you privately, and if you need more assistance, feel free to ask.

Regards

Dear Abbas,

I suggest you to take a look at links and attached file on topic.

Analysis of a combined piled-raft system (CPRF) of a typical ...

https://www.researchgate.net/.../318753346_Analysis_of_a_combi...

Centrifuge modeling of piled raft foundation on clay - ResearchGate

https://www.researchgate.net/.../245410975_Centrifuge_modeling...

3-D Modeling of Piled Raft Foundation - Spectrum: Concordia ... https://spectrum.library.concordia.ca/977288/

Design method of piled-raft foundations under vertical load ...

www.academia.edu/.../Design_method_of_piled-raft_foundations_...

Montaser Bakroun Thesis modeling of piled raft' 11.docx

library.iugaza.edu.ps/thesis/105049.pdf

pile soil interaction by finite element method in abaqus - AIKTC ...

www.aiktcdspace.org:8080/jspui/bitstream/.../aiktcDspace1992.pdf

Hi,

In most studies I reviewed on the static behavior of piled raft foundations, this interaction was considered to be frictionless (smooth). I invite you to visit my profile and find the papers on this topic. There is always a numerical finite element modeling section that explains these interaction and presents a review of previous studies in this matter:

Abbasali Taghavi Ghalesari

You can use the hard contact option in ABAQUS if you are modeling a static (and symmetric) loading condition because, otherwise, the contribution of the frictions would be prominent and must be incorporated into the analysis.

Regards