季节冻土区水泥改良路基土的温缩性能研究

Study on the temperature shrinkage property of cement modified embankment soil in seasonally frozen soil regions

基于季节冻土区冻融循环条件,利用高低温交变试验箱与静态应变仪,进行了不同配比水泥改良路基土的温缩试验研究。结果表明:水泥改良土的温缩应变呈"螺旋式"变化,温缩应变随水泥掺量增加逐渐增加,初始温度循环对水泥改良土影响较大,经历三次温度循环后水泥土温缩应变特性已相当明显且变化规律趋于稳定,土体内部物化反应也达到平稳,但多次循环后掺量6%的水泥土内部反应机理较其他掺量不同,且对温度变化的敏感度较低,温缩应变与系数相对较小。在冀北地区,掺量6%水泥土可用作季节冻土区道路的基层或底基层,为水泥土在季节冻土区的应用提供了试验依据。

Based on freeze-thaw cycling conditions in seasonally frozen soil regions,a temperature shrinkage test of cement modified embankment soil with different cement mixing amount was carried out by using high-low temperature alternating test box and static strain gauges.The test results show that the temperature shrinkage strain of the cement modified soil changes in a screw-type,and the temperature shrinkage strain increases gradually with the increase of cement content.The initial temperature cycle has a great influence on the cement modified soil.After three temperature cycles,the temperature shrinkage strain characteristics of the cement modified soil is quite obvious with a stable changing tendency,and the physical and chemical reactions of the soil have also reached a screw-type stable level.However,the internal reaction mechanism of cement soil with 6%cement mixing amount after multiple cycles has low temperature sensitivity,different from other mixtures,and its temperature shrinkage strain and coefficient are relatively small.The 6%cement mixing amount studied in this paper can be used as the base or basement layer of roads in the seasonally frozen soil regions in northern Hebei Province,which would be useful for the application of cement soil in seasonally frozen soil regions.