铁路路基膨胀土填料改良试验研究

Expansive Soil Filling Improvement Test of Railway Subgrade

用膨胀土作为铁路路基的填料会引起其上部铁路轨道的过量变形从而危及铁路的安全运行,不能直接用作铁路路基填料,必须进行改良处理。结合武康二线铁路路基试验工程,通过实地取样,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膨胀土填料的改良效果。研究结果表明: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塑性显著降低,强度大大提高,胀缩性得到了有效抑制且浸水稳定性和强度都有了明显改善,能满足时速200km铁路路基填料的要求。

Using expansive soil as the filling of railway subgrade is a cause of its excessive deformation of the upper part of the railway track which endangers the safe operation of the railway.It cannot be directly used as subgrade filling,but must be improved.In this paper,combining with pilot projects of Wuhan-Ankang 2nd railway subgrade,through field sampling,the indoor experimental research about expansive soil improved by lime is carried on,as well as the comparative analysis of expansive soil′s physical and mechanical properties before and after improvement and the improvement effects.The results show that： it is feasible to use lime as a modifier of expansive soil;the expansive soil modified by lime has significantly lower plasticity,higher strength,poorer swell-shrink characteristics,and its water-logged stability is advanced,which can meet the requirement of railway subgrade filling with speed of 200km/h.