季节性冻土区路基基床粗颗粒土填料冻胀特性研究

摘要

季节性冻土区高速铁路路基冻胀病害日渐突出，路基冻胀对施工的影响也不容忽视，研究路基基床填料的冻胀特性对路基冻胀防治具有实际意义。选取东北某客运专线路基基床底层 A、B 组填料作为试验土样，通过不同含水率、不同细粒含量、不同冻结温度条件下的冻胀试验，研究各参数对冻胀率的影响。试验结果表明：该填料冻胀率随着含水率的增加而增大，细粒含量＜15%的粗颗粒土仍会发生冻胀；该填料冻胀率随着细粒含量的增加而增大；填料冻结温度直接影响该填料的冻结过程，进而对其冻胀率产生影响。%The frost-heave defects pose an increasingly severe challenge to the high-speed railway in seasonally frozen soil areas,affecting both the train operation and the subgrade construction. It is meaningful to study the frost-heave performance of the subgrade-bed filling and provide effective treatment measures. The bottom-layer fillings of certain passenger-dedicated railway subgrade were chosen and labeled respectively as Filling A and Filling B. A parametric analysis was conducted with experimental tests. Various factors,including the moisture content,the proportion of fine grain and temperature,affected the frost-heave ratio. The results indicated that the frost-heave ratio increased with the moisture content. Such defect occurred when the fine-grained content of the coarse-grained soil stayed below 15%. Moreover,the frost-heave ratio increased with the fine-grained content. In addition,the experiment revealed that the freezing temperature of the filling directly affected the freezing process, further influencing the frost-heave ratio.