Out of yield surface (Dafalias-Manzari material)

[Taher]

Dear experts
I am new to OpenSees and i tried to run some models to verify geotechnical centrifuge results (ex. velacs project) and it was successful. But now i am trying to model sloping ground ( something like sloping ground examples available online in wiki ) using same specifications and i get out of yield surface message. I checked every possible reason that why i get such large displacements and strains that causes out of yield surface issue. finally i guess my meshing can cause this problem. model is running in elastic phase ( -stage 0 of material).

So my question is: how can i mesh a slope? Is there any special trend for node coordinates or assembly of elements that i don't know?

Thanks in advance for your attention.

[aminpakzad]

please contact me pak.pakzad@gmail.com