Hello everybody,

I'm modelling an axial pulling test i.e. longitudinal soil pipe interaction. I'm using:

- C3D8 elements for the sand
- S4 elements for the pipe
- Mohr coulomb constitutive model

While I was doing a sensitivity analysis varying some soil parameters I noticed that the model is not `perfect`. If I increase the friction angle from 40 degrees to 45 degrees the soil reaction force measured during the axial pulling decrease. Obviously if the friction angle increase the soil reaction must increase. From .odb file it is evident an increase of stress around the pipe much higher in the case 40 degrees respect to the case 45 degrees. At the same manner if I increase the dilation angle over 10 degrees the reaction force start to decrease.

Any suggestion?

Thank you for your time

• http://files.engineering.com/getfile.aspx?folder=e99f65b1-6cf1-4ac6-9047-13