二灰改性黄土用于季节性冰冻地区路基抗冻性能研究

中国季节性冻土地区分布广，冬季路基易吸水冻胀导致边坡失稳和路面翻浆唧泥病害。采用石灰与粉煤灰对黄土进行联合改性的抗冻性能室内试验，通过对冻融循环前后不同石灰和粉煤灰配比下联合改性黄土的无侧限抗压强度、渗透系数、抗剪强度等物理力学特性的试验研究，选取性能较优的联合改性黄土的最佳配比。结果表明:石灰、粉煤灰联合改性技术不仅能提高黄土的无侧限抗压强度、降低其渗透系数，而且还能明显提高路基抗冻性能；联合改性黄土最佳掺配比为石灰和粉煤灰用量分别为黄土用量的6 %，8 %左右。

Study on Anti-freezing Performance of Roadbed in Seasonal Frozen Area with Lime and Fly Ash Combined Modified Loess

Seasonal frozen soil distributes widely in China, easy water absorption and frost heaving in winter lead to roadbed slope instability and pavement slurry and mud disease. In this paper, the indoor test of frost resistance of combined modification of loess with lime and fly ash is adopted. Through the experimental study of the physico-mechanical characteristics of unconfined compressive strength, permeability coefficient and shear strength of the combined modified loess under different lime and fly ash ratios before and after the freeze-thaw cycle, the best ratio of the combined modified loess with better performance is selected. The test results show that the combined modification technology of lime and fly ash can not only improve the unconfined compressive strength of loess and reduce its permeability coefficient, but also significantly improve the frost resistance of loess. The optimum mixing ratio of the combined modification loess is about 6 % and 8 % of the amount of lime and fly ash used in loess respectively.