EPS颗粒改良土作为寒区路基填料的抗冻性能研究

为研究EPS颗粒改良土作为寒区路基填料的抗冻性能，以冻胀率及割线模量为评测指标对改良土的抗冻性能进行了测试分析。通过冻胀率试验，获得了不同EPS颗粒掺量下冻胀率与冻融循环次数的关系。通过不同围压下的室内三轴试验，获得了改良前后土体割线模量随冻融循环次数增加的衰减规律，据此定义了无量纲单位残余割线模量比并建立了其与冻胀率的关系。结果表明：EPS颗粒的掺入对改良土的抗冻性能有明显的提升，有效地降低了改良土的冻胀率，随着EPS掺量增加，冻胀率逐渐减小，二者大致呈指数关系。冻胀率在冻融的初期发展较快，后期趋于平缓。改良后割线模量的衰减有大幅度的降低，割线模量随着冻融循环次数增加而逐渐减小，残余割线模量比与冻胀率之间近似呈二次抛物线关系。利用灰色理论可以对改良土割线模量的衰减规律进行预测，模型预测结果精度较高，可以作为路基工程冻害防治的参考。

Study on frost resistance of EPS particles modified soil as subgrade filler in cold regions

In order to study the frost resistance of EPS particles modified soil as subgrade filler in cold regions, the frost heave ratio and secant modulus were used as indicators to evaluate the frost resistance of modified soil. The relationship between frost heave ratio and the freeze-thaw cycles under different EPS particles contents was obtained by frost heave test. The attenuation law of secant modulus was obtained through the triaxial test under different confining pressures and under various freeze-thaw cycles. The dimensionless unit residual secant modu-lus ratio was defined to establish the relationship with frost heave ratio. The results show that the incorporation of EPS particles has a significant improvement in the frost resistance of modified soils, which effectively reduces the frost heave ratio of the modified soil. With the increase of EPS dosage, the frost heave ratio decreases gradually, and between the two there are a roughly exponential relationship. The frost heave ratio develops rapidly in the initial stage of freeze-thaw cycles, and tends to be gentle in later stage. The attenuation of the secant modulus after the improvement is greatly reduced. The secant modulus decreases gradually with the increase of freeze-thaw cycles, and the residual secant modulus ratio is approximately a parabola with frost heave ratio. The attenu-ation of secant modulus with the freeze-thaw cycles can be predicted by using grey theory. The model prediction results are accurate, which would be useful for frost damage prevention of subgrade engineering.