砂岩冻融破坏机理及冻融力学性质研究初探

选取2008年极端冰雪受灾地区的灰色砂岩，通过扫描电镜试验、冻融循环试验和单轴压缩试验，探究了砂岩在极端冰雪条件下的破坏机理和物理力学性质。试验结果表明，灰色砂岩的冻融破坏主要是沿着试样沉积层理面（微结构面）出现、发展和贯通，层理面的破坏源于碎屑颗粒间填隙物的破坏；砂岩宏观冻融破坏模式的类型和冻融循环后力学性质的变化与其发育的沉积层理密度关系密切；表征砂岩单轴抗压强度或弹性模量随冻融循环次数变化关系的模型中，直线模型最为实用。

Elementary Analysis of Failure Mechanism and Mechanical Properties of Sandstone under Freeze-thaw Cycling Condition

This paper explores the failure mechanism and physical-mechanical properties of sandstone in condition of extreme ice and snow. Firstly, the gray sandstone which is collected from the disaster area of extreme ice and snow in 2008, is manufactured into standard specimen. Then, we analyze with scanning electronic microscope test, freezing-thawing cycling test and uniaxial compression test. It is shown that the freeze-thaw damage of gray sandstone appears, develops and finally links together mainly along the planes of the sedimentary layers of the sample. Furthermore, the failure of the sedimentary layer originates from the destruction of the cement in the lithic fragment. Besides, it is the density of sedimentary layers that has a great impact on sandstone macro-freeze-thaw damage model types and change of mechanical properties; among these models that describe the relationship between uniaxial compressive strength or elastic modulus and freeze-thaw cycles times, linear model is the most useful.