边缘裂缝圆盘砂岩试体III型断裂韧度量测之研究

针对含边缘裂缝之砂岩试体受反平面剪力情形进行了III型断裂韧度量测试验，搭配相关所推导之理论公式求取砂岩III型断裂韧度。研究试验条件为无围压及单轴荷重加载下进行III型断裂试验，且针对试体受高温后之性质改变为变量条件加以探讨。研究结果表明，以该方式进行III型断裂韧度之量测，为可靠且稳定；砂岩经历温度在200 ℃前，试体III型断裂韧度会提升，之后呈现下降，到600 ℃，下降趋于平缓；随着烧结温度的提升，单压强度、动态杨氏模量、动态泊松比与III型断裂韧度皆有下降之趋势，且试体出现熔融样态，表面出现明显微裂纹。

Study of measuring mode III fracture toughness of sandstone disk specimen with an edged crack

This study conduct a mode III fracture toughness measurement test on a sandstone specimen with an edge crack in an anti-plane, shear-loading situation and obtain the mode III fracture toughness by using derived theoretical formulas. The testing conditions do not include confining pressure, and the mode III fracture test is conducted under a uniaxial load application. In addition, the study used a change in specimen properties, caused by exposure to high temperature, as a variable condition for further discussion. The research results show that the proposed method of performing the mode III fracture toughness test is reliable and stable. Heating at temperatures up to 200 ℃ enhance the sandstone specimen’s mode III fracture toughness. The toughness decline after 200 ℃ and then leveled off after reaching 600 ℃. The uniaxial compressive strength, dynamic Young’s modulus, dynamic Poisson’s ratio, and mode III fracture toughness show a declining trend following an increase in sintering temperature. The specimen appeared to be molten, and evident micro cracks appear on the surface.