Abstract: Based on a comprehensive engineering geological investigation and supplemental explorations, a series of laboratory tests were conducted on the expansive soil and the improved soil along the Changde-Zhangjiajie Expressway. They included free swelling ratio, loaded swelling capacity, shrinkage, total swelling and shrinkage, distribution of granular particles, compressive strength, shear strength and California Bearing Ratio (CBR). Engineering properties of the expansive soil were then evaluated based on test results, which provided important guidelines for design and construction of pavement using the expansive soil as subsoil。