Why pressure doesn't travel downwards in Richards Mechanics

Hi, all.
I’m doing a rainfall simulation using Richards Mechanics and applying a Neumann boundary at the top of the model to represent rainfall, but the results I’m getting are a bit strange, why doesn’t the pressure transfer downwards here?
My model has a top z-coordinate of -30 and a bottom z-coordinate of -45, and sets the z-coordinate of the groundwater level at the beginning to -40, here’s my file, hopefully someone can help me. Thanks.


rock_flux.zip (35.2 KB)

Hi, this is probably due to too small time step or too coarse mesh in the vertical direction.

Hi, I tried refining the vertical grid and increasing the time step, but the result is still unchanged. And I set the initial pressure state, but it looks as if there is no relationship with the initial state pressure during the run, but according to the normal logic, the pressure state should change based on the initial state, I don’t know why this happens, is it because my parameter setting is wrong?

Best regards!