关键词: 断裂韧度, 饱水砂岩, 抗拉强度, 软化系数, 相关性

Abstract: Rock damage and fracture is closely related to each other, and there is a specific relationship between strength criterion parameters and fracture toughness of fracture theory. Based on these, a compact test scheme was designed for three-point bending fracture toughness test, compressive strength test and tensile strength test of sandstone under the states of dry and saturated. The test results show that after saturated in water, the softening effect of modeⅠfracture toughness of sandstone was obviously, and the fracture toughness ratio of water-saturated sample and dry sample is close to the sandstone softening coefficient of the compressive strength, showing a similar softening effect. Meanwhile, the relationship of the modeⅠfracture toughness and the tensile strength was discussed through theoretical analysis; and a large number of experimental data was used to verify the analysis results. As a result the analysis results can provide a theoretical basis for the previous statistical fitting formulas between modeⅠfracture toughness and the tensile strength. Finally, statistics and analysis of the relationship between modeⅠfracture toughness and compressive strength, cohesion, friction angle and some other strength parameters was made. Research results have an important reference value for the study of the correlation between modeⅠfracture toughness and strength parameters of sandstone, and the related test methods, test results and conclusions can provide favorable evidences for the experimental research of other types of rocks.

Key words: fracture toughness, water-saturated sandstone, tensile strength, softening coefficient, correlation