Mohr Coloumb Contact Model

Hello,

I am trying to simulate a rock slope problem. I need to specify " Cohesion as well as Friction Coefficient " in the interaction module. 

But in Interaction Module only Fricition Coeffiecient can be specified and there is no provision of cohesion.

If someone can suggest me a way to model cohesion as well as friction in interaction. I want my contact to be like a mohr coulomb contact model.

I have Vuinteraction routine with me, and if someone can tell me a way to model mohr coulomb contact model through Vuinteraction, I will be thankful.