Several experimental producers including using suction control to interpret swelling pressure for compacted bentonite have become generally accepted in geo-environmental engineering. This study focuses on both soil-water characteristic curve and swelling pressure of compacted bentonite. Soil-water characteristic curve was measured using vapour pressure technique. Compacted bentonite having two different soil suctions were prepared for swelling pressure tests. This new swelling pressure testing apparatus was developed in order to measure swelling pressure in a constant relative humidity environment. The apparatus was mainly consisted of the triaxial chamber and relative humidity control circulation system. The total volume of compacted bentonite was maintained constant during absorption process. This study demonstrates the influence of soil suction on swelling pressure under permitted adsorbed water into the compacted bentonite. Change of soil suction influenced the maximum swelling pressure of compacted bentonite.
