Long Term Building Performance over an Injected Subgrade

Several foundation designs and stabilization methods are used with varying degrees of success to cope with the problem of expansive clays. Many of these methods are very expensive, therefore alternate technology that is both cost and performance effective has been developed. This paper presents a case history with pre- and post- stabilization test data for a 4-building project where pressure injection of lime and water was used to preswell weathered clay-shale to a depth of 10 feet. Use of pressure injection technology economically reduced post construction movements to 0.5 inches to 1.8 inches over a 7 year monitoring period. Movements observed have been upward, with no settlement or shrinkage related movements related over the observed period