青藏铁路清水河段细粒土用作路基填料问题的探讨

On Fine Soil Used as Subgrade Filling Material on Qingshuihe Section of the Qinghai-Tibet Railway

用作冻土区的路基填料,在冻胀敏感性方面有其特殊的要求,为了分析青藏铁路清水河段细粒土是否可用作冻土区路基填料,收集了该区粘性土、粘砂土和细粒含量较多的砾砂,分别用两种密实度进行了土的室内物理、力学实验、冻胀实验以及毛细管上升高度和含盐量实验。从变形、稳定和冻胀敏感性方面综合分析实验结果后,提出了该区使用粘性土的局限性及其改良途径。根据试验得出:增加土的压实密度,控制施工中的含水量,采取严格的隔热、隔水措施,对防治或减少路基冻胀可起到较显著的效果。

The subgrade filling materials used in frozen districts have special requirements of their sensitivity to frost heaving. In order to analyze the possibility of using the fine soil as filling material on Qingshuihe section of the Qinghai-Tibet railway, clay soil, sand clay soil and cobble sand containing high percentage of sand were collected in the district and tested with two different compactness. We carried out the inhouse physical test, mechanical test and frost heaving test, as well as capillary height test and salt ingredient test. The test results were analyzed comprehensively in deformation, stability and frost heaving sensitivity. The test result is that there is a limit of using the clay soil in this area and there are ways of improving it. It is concluded that when the compactness of the soil is increased,there is less water content in the soil and good heat and water insulation is applied, it will produce obvious effect of preventing or reducing the subgrade frost heaving. 