As I understand your problem, the soil in front of your shed is heaving at a greater rate than the soil supporting the shed. Consequently reducing the heave of the shed (following the directions outlined above) while not addressing the door sweep area may not completely remedy the problem...
You can obtain a design procedure for concrete pavements from the Portland Cement Association (PCA). I think you can download a pdf from their website for free. This procedure has been used succesfully to design high load high traffic highways.
Regardless of the design procedure adopted pay...
Rjeffery,
If I am interpreting your queries correctly, you are really trying to characterize bearing conditions in sand in real time during foundation construction.
Under the right conditions you may want to consider the use of a plate load test(s) using Schmertmann's method. In a nutshell...