A footing stress model with groundwater

A fictional shallow-foundation investigation finds three meters of soil above the water table and two meters below it at the point of interest. For this exercise the upper soil has total unit weight eighteen kilonewtons per cubic meter, the saturated lower soil has unit weight twenty kilonewtons per cubic meter, and water unit weight is ten kilonewtons per cubic meter. A designer must report total and effective vertical stress before discussing strength parameters. Another designer proposes using the saturated weight and then subtracting two separate water-pressure terms. No foundation geometry, allowable stress, settlement requirement or site-specific design authorization is supplied. The purpose is to keep the stress definitions consistent and identify the evidence still needed for an actual foundation decision.