Abstract: Based on the final geotechnical investigation results, a special expansive soil investigation program was conducted for the Tianhe International Airport Third Phase Expansion Project. Through the field sampling, laboratory tests and field investigations, the expansive soils in Tianhe area are characterized to have a small expansion when absorbing moisture and high contraction after the moisture loss. In engineered fill areas with the onsite soils, the expansion indices are generally higher than the original undisturbed expansive soils. As a result of this special investigation program, the horizontal and vertical distribution limits of the expansive soil are presented and this would lead to a significant construction and operational cost saving. The preventive control measures of the expansive soil are also provided in the paper.

Key words: Expansive Soil, Free Swelling Ratio, Cation Exchange Capacity, Hydrophilic Mineral Contents, Preventive Control Measures