客运专线水泥改良黄土路基填料填筑试验研究

Test Study on Cement Improved Loess as the Filling Material for Subgrade Construction of Passenger Dedicated Line

根据郑西客运专线黄土填料水泥改良室内试验结果，选取6％水泥改良黄土路基填料进行现场填筑压实工艺及检测试验研究。通过水泥改良黄土时效性试验，确定以3h对应的最大干密度作为最终压实检测指标；采用不同压实工艺对不同厚度改良黄土填料进行压实试验，得出选定水泥改良黄土路基填料松铺系数为1．1～1．2，松铺厚度为20-30cm，最优含水率为12％，最佳的碾压方式为静压1遍、弱振1～2遍、继续静压2～3遍。路基沉降长期观测及工后沉降预测结果表明，在满足压实系数0．95的条件下，水泥改良黄土路基本体的平均沉降率为0．24‰，满足铺设无砟轨道路基的设计要求。

Combined with the indoor tests on cement improved loess as the filling material for the subgrade construction of Zhengzhou-Xi＇an passenger dedicated line, a field test applying 6G cement improved loess as the filling material in mix ratio has been conducted to study the construction techniques and the testing method on filling and compaction. Through time dependent test of cement improved loess, the maximum dry density at three hours can be used as the index for final compaction testing. Compaction tests have been carried out on cement improved loess as the filling material with different thickness by applying different compaction methods. It is deduced from the test that the loose paving coefficient of the selected cement improved loess as the filling material of subgrade is 1.1~1.2; the loose paving thickness is 20~30 cm; the optimum moisture content is 12%; the optimum grinding and compaction method is 1 static compaction, then 1~2 weak shake, and finally 2~3 static compaction. Results of the long term observation of subgrade settlement and the forecast of after the post-construction settlement indicate that the average sedimentation rate of cement improved loess for subgrade body is 0. 24‰ under the condition of satisfying the compaction coefficient 0.95, which meets the design demand for laying the subgrade of ballastless track.