高速铁路改良粗颗粒填料冻胀特性试验研究

Experimental Study on Frost Heaving Characteristics of Improved Coarse Grain Filling for High Speed Railway

针对寒区高速铁路出现的路基冻胀问题,为改良其渗透性和冻胀特性,从路基的粗颗粒填料入手,加入无机材料进行试验,并以冻胀率不超过0.1%为标准,研究粗颗粒填料级配碎石的改良材料类型、最佳配比等技术参数。结果表明:相对于石灰和粉煤灰,掺入水泥可以大幅度减小级配碎石的渗透系数和冻胀率,从而减少水分向填料内部的渗透以及抑制填料的冻胀;在开放补水的冻胀试验条件下,在分别掺入15%,20%和25%粉土的级配碎石中对应掺入3%,5%和5%的水泥,可将冻胀率控制在0.1%以内,说明在粗颗粒填料中掺入水泥后,适当增加粉土的含量并不会使填料产生过大的冻胀变形,从而解决寒区高速铁路路基的冻胀变形问题。

Based on the problem of the frost heaving of high speed railway subgrade in cold regions, for improving the characteristics of permeability and frost heaving, the inorganic materials were added in the coarse grain filling through experimental study. The technical parameters for the improved material type and the optimum ratio were concluded with the standard of the frost heaving ratio below 0. 1%. The results show that, the mixed cement can greatly reduce the permeability coefficient and the frost heaving ratio of graded gravel compared with the lime and fly ash. Accordingly, the cement can reduce the moisture permeability to the internal filling and control the frost heaving of filling material. Under the frost heaving test condition of open replenishment, the graded gravel respectively with 15%, 20% and 25% of silt was correspondingly mixed with 3%, 5% and 5% of cement, thus the frost heaving ratio can be controlled within 0. 1%. It indicates that, with the cement adding in the coarse grain filling and the appropriate increasing of silt content, the excessive deformation of filling will not occur. Consequently, the problem of frost heaving can be solved for the high speed railway subgrade in cold regions.