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 degrees C. 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.