Expansion Potential of Compacted Fine-Grained Soils Using Suction Measurements

Fine-grained soils in arid climates are most often unsaturated. If such soils have a swelling potential, their expansive pressure must be determined for structural design. Hitherto employed swelling test methods are time consuming and not reliable. Testing methods based on suction potential measurements are being introduced in order to evaluate the expansive potential.

Swelling test results on three fine-grained soils are described in the paper. Two testing systems were used: (1) a traditional method of constant soil volume and (2) a proposed method utilizing suction pressure measurements. The tested soil samples were characterized by different consolidation initial-moisture-content conditions. The test results presented herein were used to develop a mathematical relationship between expansive pressure and suction pressure for a given soil. A design procedure for estimating swelling pressure is proposed in the paper.