冻融循环条件下水泥土损伤劣化特征研究

水泥土材料目前在寒区工程建设中被广泛应用,寒区气候温度交替变化,对水泥土各方面性能影响较大,因此,研究冻融循环条件下水泥土的损伤劣化特征对于寒区工程建设和工程设计具有重要的参考价值。将取自新疆某边坡的原状土与普通水泥配制成水泥土,在冻结温度为-20 ℃、融解温度为20 ℃条件下分别进行0,3,9,15次冻融循环试验,不同循环次数后对水泥土试样进行单轴抗压强度试验和质量变化测定。在此基础上,采用扫描电镜分析水泥土的微观结构变化,探讨冻融循环条件下水泥土的损伤劣化机制。结果表明,水泥土的抗压强度和剩余质量随着冻融循环次数的增加而降低,水泥土抗压强度随冻融循环次数的变化规律可用关系式R_c=-0.11n+3.29表达。

Degradation and Deterioration Behaviors of Cemented Soil under Cyclic Freezing-thawing

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.