消石灰改良膨胀土室内试验研究

Studies on Lime Treated Expansive Soil

膨胀土因其显著的胀缩特性不能直接用作路基填料,基于某铁路项目,将3%、5%、7%的消石灰掺入膨胀土中进行改良,研究了不同掺量的改良膨胀土不同龄期的自由膨胀率、胀缩变形以及抗剪强度参数随干湿循环次数的变化规律.结果表明:3%以上掺量的消石灰即可有效地抑制膨胀土的自由膨胀率;5%以上掺量则可有效抑制干湿循环过程中膨胀土裂隙的发展,大幅减少每次干湿循环的胀缩变形,保证抗剪强度不被削弱.

Expansive soil can not be directly used as the roadbed filler owing to its remarkable expansion and contraction properties. Based on a railway project, 3%, 5%, 7% dosage of the lime were incorporated in expansive soil, the free swelling ratio of expansive soil improved between different contents and different ages, the shrinkage deformation and the shear strength parameters with variation were investigated. The results showed that： more than 3% dosage of the lime can effectively suppress the free swelling ratio of the expansive soil; more than 5% dosage of the lime can effectively suppress the cracks of wet and dry cycle inhibition in the development of expansive soil, which dramatically reduced each expansion and shrinkage deformation for the cycle of wet and dry, and ensured that the shear strength was not impaired.