Hello PLAXIS team,
I am modeling a 3x3 m footing on surface of cohesionless soil with friction angle = 30 deg, E = 20 MPa and Poisson ratio = 0.33. The bearing capacity from the PLAXIS model is 3300 kN at 175 mm deformation, and it will increase further up to 4500 kN or more with the increase of deformation. However, the calculated bearing capacity using classical Meyerhof or Hansen bearing capacity equation is about 2600 kN. It is a very simple model but unable to predict the classical bearing capacity equation. Are you able to review and comment if I send my PLAXIS file?
Regards,
Dear Abraham,
Sure, please send your request and PLAXIS 3D file via submitting a service request https://apps.bentley.com/srmanager/ProductSupport
Please use the Pack Project option to send files.
Not able to access the service request link. Am I able to send you the onedrive link to the file. I also submitted the file already using the "File" in the above.
I submitted the PLAXIS file through "Communities Secure File Upload". The OneDrive link also provided here:
https://wsponline-my.sharepoint.com/:u:/g/personal/abraham_mineneh_wsp_com/EdDfo2aINWRIg6hzJAV380oBnLSz7-3L7zBBJh6mz0uCtg?email=Micha.vanderSloot%40bentley.com&e=eJcf3l
In general, when comparing a numerical analysis with an analytical solution it is important to realize that the bound and uniqueness theorems of limit analysis are only valid for ideal materials that exhibit associated perfect plasticity, i.e. no post-yield hardening or softening, and an associated flow rule.The latter requirement means that, in the case of a Mohr-Coulomb soil, the theorems are only applicable if the dilation angle ψ is equal to the friction angle φ.
Information can be found online, for instance, examples published by Stefan Van Baars (100 year Prandtl's Wedge):www.researchgate.net/.../319393063_100_Year_Prandtl's_Wedge_Intermediate_report
Back to the case that you presented, based on my calculations, the analytical solution from Meyerhof gives a bearing capacity of ~5500kN.
With PLAXIS 3D the best way to check this solution is by using the rigid body feature using displacement as translation condition in the z-direction. This gives significantly better results and comparable to Meyerhof's equation value, even without considering φº = ψº (as mentioned above).
If you have further concerns or questions, please submit a service request so that one of our support engineers can assist you:apps.bentley.com/.../ProductSupport