If the groundwater table at a site rises from 5 meters below the ground surface to the ground surface, how does the effective stress at a point 10 meters deep change?

The effective stress at a point 10 meters deep changes significantly when the groundwater table rises from 5 meters below the ground surface to the ground surface. This change is governed by the relationship between total stress, pore water pressure, and effective stress. We define total stress (σ) as the total pressure exerted by the weight of both soil solids and water above a given point. Pore water pressure (u) is the pressure exerted by the water within the soil's pore spaces. Effective stress (σ') is the stress carried by the soil solid particles, which is responsible for the soil's strength and deformation, and it is calculated as the total stress minus the pore water pressure: σ' = σ - u. To determine the change, we will consider two scenarios at a depth of 10 meters, assuming a typical dry/moist unit weight of soil (γ_dry) as 18 kN/m³, a typical saturated unit weight of soil (γ_sat) as 20 kN/m³, and the unit weight of water (γ_w) as 9.81 kN/m³. Scenario 1: Groundwater ta....