The expansive soil is studied as the object of the research in Yichang City

Hubei Province. Different content of lime

cement

coal fly ash and weathered sand are put into the expansive soil to modify it

then the unconfined compressive strength is tested under standard conditions with the days of 7

14

28 d. The research shows that the unconfined compressive strength can be improved in an effective way with the above four materials

the strength of expansive soil with cement grows obviously in the first 14 days

then the growth rate slows down with the curing age goes up; the unconfined compressive strength of expansive soil with lime is nearly in a linear growth trend with the curing age goes up; the unconfined compressive strength of expansive soil with coal fly ash is also in a linear growth trend

but the unconfined compressive strength is smaller than that of expansive soil with lime; the curing age has little effect on the unconfined compressive strength of expansive soil with weathered sand.