Hello – I was wondering if anyone could help me with the following problem:

I am using Wallap for the first time and have come across something strange. The design is a propped retaining sheet pile wall.

The bending moment and displacement diagrams indicate that it is free earth support. However, the net pressure diagram shows the passive pressure changing to active right at the bottom of the pile – indicating fixed earth support.

When I manual calculate the design using free earth method, I also get a prop force 27% LESS than the Wallap prop force.

The only difference I can see is the Wallap reports a drop in passive pressure for some reason at the bottom of the pile.

Can anyone please explain why/how:
1) A manual calc can be less than the wallap report in terms of resistance required (i.e. I thought Wallap would have optimised the force)
2) Why the net pressure changes from passive to active right at the bottom of the pile (even though the bending and deflection diagram shows free end)

I've uploaded a snapshot of the diagrams https://files.engineering.com/getfile.aspx?folder=...