冻融循环作用下玻璃纤维改性水泥土抗压强度特性研究

Study on the Compressive Strength Characteristics of Glass Fiber Reinforced Cement Soil under Freeze-Thaw Cycles

摘要: 为解决季节性冻土区水泥土路基、地基在冻融循环作用下强度衰减快、易开裂失稳的工程难题，以玻璃纤维作为增强材料，掺量分别为0‰、4‰，制备玻璃纤维改性水泥土(GC)，开展冻融循环作用下的无侧限抗压强度试验研究。以冻融循环次数为控制变量，分别取0、1、3、5、7次，分析冻融作用对水泥土抗压强度的影响规律。结果表明：养护龄期为7 d时，水泥土的无侧限抗压强度随着冻融循环次数的增加而降低，添加玻璃纤维的水泥土，无侧限抗压强度的降低率减小，可知玻璃纤维的添加能够提升水泥土抵抗冻融的能力；冻融后试样峰值应变较未冻融试样降低5%~24%，说明冻融循环阻碍了水化反应，削弱了材料的抗变形能力。该研究可为水泥土地基、路基加固等工程的抗冻设计与应用提供理论参考。

Abstract: To address the engineering problems of rapid strength degradation and cracking instability of cement soil subgrades and foundations in seasonal frozen regions under freeze-thaw cycles, this study used glass fiber as the reinforcing material with contents of 0‰ and 4‰ to prepare glass fiber reinforced cement soil (GC), and conducted unconfined compressive strength tests under freeze-thaw cycles. Taking the number of freeze-thaw cycles as the control variable (0, 1, 3, 5, and 7 times), the influence law of freeze-thaw action on the compressive strength of cement soil was analyzed. The results show that when the curing age is 7 days, the unconfined compressive strength of cement soil decreases with the increase of freeze-thaw cycles, while the reduction rate of unconfined compressive strength of cement soil with glass fiber is smaller, indicating that the addition of glass fiber can improve the freeze-thaw resistance of cement soil. After freeze-thaw cycles, the peak strain of the samples decreases by 5%~24% compared with the unfrozen-thawed samples, indicating that freeze-thaw cycles hinder the hydration reaction and weaken the deformation resistance of the material. This study can provide theoretical reference for the design and application of anti-freezing measures in cement soil foundation and subgrade reinforcement projects in seasonal frozen regions.