无砟轨道路基上拱原因试验研究

摘要

A railway line in the northwest of China with subgrade heaving problems was investigated,and 6 typical sections were studied experimentally,including the expansive characteristics,soluble salt content and mineral components of subgrade f illings and foundation.The results show that the expansion of mud stone causes subgrade heaving,and the extent of the heaving depends on the soluble salt content in foundation and subgrade f illings. Besides,the formation of ettringite and thaumasite during the process of sulfate attacking cement treated aggregates can also result in subgrade heaving.Waterproof ing and drainage measures are suggested to constrain the subgrade heaving.%对我国西北地区一路基上拱变形较严重的无砟轨道线路调研后,选择6个典型路基上拱工点进行了现场取样与试验,分析地基土与路基填料的膨胀性、易溶盐含量和矿物成分.研究结果表明:泥岩地基遇水膨胀引起了路基上拱;路基上拱变形与地基土、路基填料中易溶盐含量呈正相关;易溶盐侵蚀水泥改良填料形成钙矾石、硅灰石膏的过程也可能引起路基上拱.建议上拱地段的路基采取防水、排水、疏水措施.