Subgrade construction control parameters for lime-treated expansive soils

Taking the slope of expansive soil as the research object,based on the analysis of construction control parameters of lime-treated expansive soil,this paper did relevant tests on the strength and expansive properties of the soil.The results show that the optimal construction water content of lime-treated expansive soils should be within wopt2%~4%.The strength of lime-treated expansive soil increase fast in 7days,and after 7days it tends to be stable,the reasonable lime rate has great influence on the strength improvement of lime-treated expansive soil.The results show that with the increasing of llime rate the plasticity index decreases,and the free swelling ratio decreases first and then increases.The properties of expansive soil mixed with lime will be improved rapidly,which will be finished in first 24 h,and increasing curing of time has little influence on it.Combined with the results of strength and expansive properties tests,the method for the determination of the subgrade construction control parameters with the expansive properties as the main control indexes,and the strength as the confirmation index is proposed.