Discussion Forum

Dear All:
I am a beginner of using COMSOL for soil mechanics study.
Recently, I am trying to study the influence of subsurface flow process on soil deformation.
I use Richards Equation to get the pore water pressure and groundwater level in a slope.
And try to couple the Richards Equation to the soil mechanics module.

Firstly, I successfully coupled Richards equation with a Linear Elastic Material module,
the coupling is through the body load, which is depend on the water content results calculated by Richards equation. And this model can simulated the transient process of subsurface flow and soil elastic deformation

Secondly, I am trying to add soil plasticity in this model, I use Mohr-Coulomb failure criteria, but many problem existed in this model. I can not use this model for time dependent modeling, because the software always report me mistake: Failed to find consistent initial values, Failed to compute elastoplastic strain variables, last time step is not converged.
But when i try to use static study for soil plastic computation, I can only get the same results not matter how different the groundwater level is. I guess the coupling is not totally effective.

I guess many researcher is working with this topic,
Could anybody introduce some skill for Subsurface Flow and Soil Plasticity coupling?
Thank you in advance.