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针对季节性冻土区的特殊环境,对冻融循环后的水泥改良土进行系列动静试验,研究土体的物理性状、力学特性与冻融次数、冷冻温度的关系。结果表明,反复冻融作用改变了土体的性状,这一改变过程是使土体内部结构从不稳定态向动态稳定平衡状态发展的过程;其应力—应变关系呈应变软化型,表现为脆性破坏,存在明显的剪切面;动荷载作用下,水泥改良土试样存在一临界状态,其破坏过程分为3个阶段:微裂纹出现、裂纹扩展和整体错动;经历3次冻融作用后,其临界动应力随冻融次数下降趋势变缓;动应力和冻融作用对水泥改良土的回弹应变影响显著;回弹模量存在一临界值,其值随冷冻温度的降低而降低。
According to the special environment of seasonal frozen soil area, a series of static and dynamic tests were carried out on the cement modified soil after the freeze-thaw cycle to study the relationship between the physical and mechanical properties of soil and the number of freezing and thawing cycles and the freezing temperature. The results show that repeated freezing and thawing has changed the characteristics of soil. This process of change makes the internal structure of soil develop from unstable state to dynamic stable equilibrium. The stress-strain relationship is strain softening and brittle Under the action of dynamic load, there is a critical state in the specimen of cement-modified soil. The failure process is divided into three stages: the appearance of microcracks, the propagation of cracks and the overall dislocation; the three freeze-thaw cycles The dynamic stress and freeze-thaw effect have a significant impact on the springback strain of cement-modified soil. There is a critical value for the springback modulus, which decreases with the decrease of the freezing temperature .