esys-escript running soil mechanics simulation

Hi, I just discovered esys-escript a couple of days ago, and my understanding of the software is that it's fundamentally a PDE solver.

If I want to simulate soil mechanical problems such as triaxial tests, 1D consolidation tests, etc., I have to abstract soil mechanical problems into a set of PDE functions and use esys-escript, correct? I also have to write my own constitutive soil models (e.g., Drucker Prager model, Mohr-Coulomb model, etc.), right?

To better ask the question, take some other FEM softwares as examples (e.g., Abaqus, Plaxis, Optum G2/G3, OpenSees), in these softwares, I only need to build the geometry of the model, pick a constitutive relation, apply load (boundary conditions), and it will give me the distribution of stress/strain, displacement, etc.

So, to accomplish the same goal, in esys-esript, I will have to input a set of PDEs that represent the mechanical problem, right?

I am just seeking for the possibility of esys-escript using in my research.
Thank you.