Here's his equivalent fluid pressures (active):
1. Lean Clays, 51 pcf (above) and 25 pcf (below)
2. Clayey Sands, 42 pcf (above) and 21 pcf (below).
So if there's water accumulated behind the wall, then I will use 25+62.4=87.4 pcf. correct me if I am wrong with the numbers. Thanks.