关键词: 水泥土, 冻融循环, 损伤劣化, 力学特性, 微观特征

Abstract: Cemented soil materials have been widely used in engineering construction in cold regions where climate and temperature have great influence on the properties of cemented soil. Researching the degradation and deterioration behaviors of cemented soil under cyclic freezing-thawing is of valuable reference for the construction and design of similar projects in cold regions. In this article, we mixed undisturbed soil from a slope in Xinjiang with ordinary cement to prepare the cemented soil for test, and conducted cyclic freezing and thawing tests of 0, 3, 9 and 15 times with the freezing temperature at -20 ℃ and thawing temperature at 20 ℃. Uniaxial compressive strength tests and quality analysis were performed after different cycles. On this basis, the microscopic structural changes of cemented soil were analyzed by using scanning electron microscopy (SEM) to investigate the degradation and deterioration mechanism of cemented soil under cycles of freezing and thawing. Results showed that the compressive strength and residual quality of cemented soil samples decreased with the increase of freezing-thawing cycle times, and the regularity of changes between freezing-thawing cycle times and compressive strength can be expressed with the fitting relation: R_c=-0.11n+3.29.

Key words: cemented soil, cycle of freezing and thawing, damage and deterioration, mechanical behaviors, microscopic characteristics