基于巴西劈裂与扫描电镜的板岩冻融损伤试验研究

Research on Freeze-Thaw Damage of Slate based on Brazilian Splitting and Scanning Electron Microscopy

为研究冻融循环作用对板岩抗拉强度及微观结构的影响,以饱和炭质板岩为研究对象,对其进行不同周期的冻融循环试验,然后采用巴西劈裂试验与扫描电镜试验,分析板岩试样冻融力学性能变化与微观结构特征变化。研究结果表明:在冻融循环作用下,板岩固体质量逐渐减小,饱和质量先缓慢增加后迅速递减,抗拉强度逐渐降低,板岩受荷破裂面由脆性破坏向塑性破坏转变;随着冻融循环的进行,板岩基质间胶结作用降低,孔隙结构连通、扩展,孔隙结构复杂程度增大,破裂面分形维数逐渐增大,板岩冻融损伤变量逐渐增大,冻融循环50次后,板岩试样冻融损伤程度约为39%。

To explore the effect of freeze-thaw cycling on the tensile strength and micro-structure of slate,saturated carbonaceous slate is taken as the research object and subjected to freeze-thaw cycling tests at different cycles.Then,Brazilian splitting tests and scanning electron microscopy tests are used to analyze the changes in freeze-thaw mechanical properties and micro-structure characteristics of slate samples.The research results indicate that under the action of freeze-thaw cycles,the solid mass of slate gradually decreases,the saturated mass first slowly increases and then rapidly decreases,and the tensile strength gradually decreases.The fracture surface of slate under load changes from brittle failure to plastic failure.As the freeze-thaw cycle progresses,the cementation between the slate matrix decreases,the pore structure is connected and expanded,the complexity of the pore structure increases,the fractal dimension of the fracture surface gradually increases,and the freeze-thaw damage variable of the slate gradually increases.After 50 freeze-thaw cycles,the freeze-thaw damage degree of the slate sample is about 39%.