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为探究冻融循环对地基土的力学性质的影响,本文以张家口市区内某工地地基填土为研究对象,在室内进行单向冻融试验、静三轴剪切试验和电镜图像采集。结果表明:(1)土体在经过第1次冻融循环后,围压越大土体的压缩模量的折减越大;(2)土的强度参数随着冻融循环次数增加发生改变,内摩擦角不断增大,而粘聚力则不断减小;(3)随着冻融次数的增加,土体抗剪强度先减小后增大,在第5次冻融循环时降到最小值;(4)随着冻融循环次数增加,孔隙率不断降低,孔隙直径组成发生改变,大孔隙减少,微、小孔隙增加。
In order to explore the influence of freeze-thaw cycle on the mechanical properties of foundation soil, this paper takes the foundation fill of a construction site in Zhangjiakou city as the research object, unidirectional freeze-thaw test, static triaxial shear test and electron microscope image acquisition in the laboratory. The results show that: (1) After the first freeze-thaw cycle, the reduction of compressive modulus of soil increases with the increase of confining pressure. (2) The soil strength parameters change with the increase of freeze-thaw cycles , And the internal friction angle increased continuously, while the cohesion decreased continuously. (3) With the increase of the number of freeze-thaw cycles, the shear strength of soil decreased first and then increased and dropped to the fifth freeze-thaw cycle Minimum; (4) With the increase of the number of freeze-thaw cycles, the porosity decreased continuously, the pore diameter changed, the macropores decreased and the micro and small pores increased.