Hi there,
pretty impressive work!
I tried out the software a little bit and I encounter an issue with the "remove/delete" function for loadings (any geometric model with loading). After I remove the loading and recalculate the model there should only be stress due to the selfweight of the soil. Instead, contour plots show that there are still all the nodal forces left. They seem to be locked in even after I removed the loading and recalculated the model.
I managed to obtain the proper stress distribution (only stesses due to selfweight of the soil) only after I set the initial nodal stresses of the whole area of the model and the element stresses manually to zero and recalculation.
I hope this comment helps.
Cheers,
Christoph