Experiment on Cement Proportion and Mixing Technology for Expansive Soil Modification

Expansive soil has properties such as expanding when encountering water, shrinking and crazing when losing water. Mixing with certain proportion of cement is the main method to modify expansive soil now. According to the field modification experiment on expansive soil which has been done in 3rd section of Changjiang-to-Hanjiang water diversion project, the paper researched the modification effect of different kind of expansive soil that modified by different cement proportion, and modification effect that depends on different size of broken soil mixed in the field. The experiment result shows that, for the medium and weak mixed expansive soil and medium expansive soil in study area, the optimal cement proportion is 4% and 6%. The free swelling ratio of mixed expansive soil can be decreased below 40% by any broken size, and the medium expansive soil can be modified effectively only when the biggest broken size is less than 31.5 mm by controlling the moisture content and improving mixing technology.