Swell Potential Versus Overburden Pressure

Data were collected and reviewed pertaining to one-dimensional vertical free-swell tests performed on existing fill soils from various projects located in Southern California. The purpose of reviewing the data was to evaluate the effect of overburden pressure on the swelling potential of expansive soils. The swell tests were performed on relatively undisturbed specimens at the in-place moisture content and density under the actual overburden pressure. The data indicate that at an overburden pressure of approximately 1400 lb/ft2 (67 kPa) or greater, the swell potential generally decreases to less than 1%.