铁路路基膨胀土填料的石灰改良试验研究

研究目的：膨胀土的改良是膨胀土工程地基处理研究领域中的重要课题之一，已受到岩上科学工作者和工程师的普遍关注。合宁铁路沿线粘土具中-弱膨胀性，不能直接用作铁路路基填料，必须进行改良处理。 研究方法：本文结合合宁铁路路基试验工程，进行膨胀土填料的室内石灰改良试验研究，对比分析膨胀土改良前后的物理力学性质和胀缩性，及膨胀土填料的改良效果。 研究结论：用石灰作为膨胀土的改良剂是可行的；经石灰改良处理后膨胀土的颗粒组成、物理性质、胀缩特性均有明显改善，力学强度及水稳特性得到提高，能满足铁路路基填料的要求；石灰掺灰比中膨胀土为6％，弱膨胀土为5％；石灰宜采用三级标准以上的高等级石灰，采用低等级石灰改良时应相应增加石灰的掺入量。

Experimental Study on Improving Expansive Soil Filling of Railway Subgrade with Lime

Research purposes: The melioration of expansive soil is one of the important problems in the field of expansive ground treatment, which is commonly concerned by geotecnical workers and engineers. The dilatancy of the clay along the Hefei-Nanjiang railway is between medium and low grade,so the clay can not be directly used as the backfill of the subgrade and has to be amelionratied. Research methods:In combination with the subgrade test project of Hefei-Nanjiang railway, the indoor experimental research is made on improving expansive soil with lime, the comparison and analysis are made of physical and mechanical properties and the swell-shrink characteristics of expansive soil before and after imprvovement. Research conclusions:It is feasible to use lime as ameliorant of expansive soil.The component of granule, physical and mechanical properties and the swell-shrink characteristics of expansive soil with lime are obviously ameliorated, the mechanical strength and water stabilization are improved,and the requirement of the backfill of the railway subgraden can be met. The ratio of the lime is 6 % in the medium-grade expansive soil and 5 % in the weak-grade expansive soil. The higher-grade lime over third-grade should be used and more lime should be used when using low-gradel lime.