Abstract:To solve the problem of foundation treatment in the construction of an airport runway in an expansive soil zone, we used the expansive soil in the Ankang area, Shaanxi province as our research object. To determine the construction control parameters of lime-treated expansive soil, we carried out relevant tests on the strength and expansive properties of the soil. The results show that with an increase in the quantity of lime, the optimum moisture content increases, the maximum dry density and the swelling shrinkage potential decreases, and the quantity of lime and the maximum dry density is nonlinear. When the amount of lime is 9%, the regularity of the swelling change rate is strong. The California bearing ratio (CBR), which is related to factors such as compaction and water content, does not increase with an increase in the compaction coefficient. The proportion of added lime had a greater influence on the strength of lime-treated expansive soil. When the amount of lime is 9%, the CBR was higher than for other proportions. Under the same compaction coefficient of expansive soil, with lime dosages of 3% and 6%, the compressibility is relatively similar. When the lime dosage is increased to 9%, the compression significantly decreased. Based on these test results, we propose the use of lime for expansive soil improvement in runway ground treatment, as well as a method for determining the subgrade construction control parameters with respect to the expansive properties as the main control indexes, and strength as the confirmation index.
