Hi, all. I have some questions about the definition of boundary condition parameters in Richards Mechanics.

First of all, the Dirichlet boundary condition is generally used to define the hydraulic head, is it used to define the displacement of the rock mass in “displacement”? Because the simulation results are the same as the parameter values defined on the boundary. I probably know that the Neumann boundary defines the flow boundary in “displacement”.

Secondly, what do the two boundaries in “pressure” mean? Because in some benchmark files, I see that “displacement” uses a Neumann boundary for one boundary, but “pressure” uses a Dirichlet boundary for it.

Lastly, both boundary condition definitions use positive or negative numbers, do they mean the same or opposite of the positive direction of the coordinate system?

Thanks！