Birmingham Alabama sits on the Appalachian Piedmont, where residual soils from weathered metamorphic rock dominate the subsurface. These soils are often unsaturated, with suction pressures that change drastically after heavy rain or drought. ASCE 7 and IBC 2021 require engineers to account for unsaturated conditions when designing foundations and retaining walls on expansive or collapsible ground. Our unsaturated soil analysis follows ASTM D6836 for soil-water characteristic curves, giving you the suction and permeability data needed for safe design. Before we run those tests, we often recommend a calicata exploratory pit to visually log the soil profile and collect undisturbed block samples.
The Piedmont residual soils in Birmingham Alabama can lose up to 80% of their shear strength when saturated. Unsaturated analysis is the only way to capture that risk.