含两组叠置X型裂隙类岩石材料单轴拉伸破坏特征

Uniaxial tensile failure properties of rock-like specimens with two overlapped X-type flaws

含裂隙岩石/类岩石试件在单轴压缩下的破坏特征已有较多研究,但对含X型裂隙试件单轴拉伸下的破坏特征尚无研究结论。对含两组叠置X型裂隙类岩石材料试件进行了单轴拉伸试验,并与对应试件单轴压缩情况的已有实验结果进行了对比,研究了含两组叠置X型裂隙类岩石试件单轴拉伸下的岩桥贯通行为及强度特征。研究结果表明:含两组叠置X型裂隙类岩石材料试件在单轴拉、压作用下的破坏模式及岩桥贯通模式表现不同,在单轴拉伸作用下含两组叠置X型裂隙类岩石试件岩桥处不会出现贯通现象;含两组叠置X型裂隙类岩石材料试件的次裂隙位置影响试件单轴拉伸强度,在主裂隙位置固定情况下,次裂隙角度与最大拉应力方向垂直时试件强度最低,次裂隙角度与最大拉应力方向相同时试件强度最高。

Although the failure properties of rock/rock-like specimens with flaws under uniaxial compression have been studied in many cases, those properties of specimens with X-type flaws under uniaxial tension have not been researched yet. In this research the crack coalescence and strength properties were studied with rock-like material specimens con- taining two overlapped X-type flaws under uniaxial tension tests. The testing results were compared with uniaxial com- pression results of specimens containing corresponding flaws. The study results show that the failure and coalescence modes of specimens with two overlapped X-type flaws under uniaxial tension tests are different from those with speci- mens under uniaxial compression tests. There is no crack coalescence at the rock bridge areas of specimens containing two overlapped X-type flaws under uniaxial tension tests. The position of the secondary flaw influences the strength of specimens containing two overlapped X-type flaws under uniaxial tension tests. The specimen with a second flaw verti- cal to the maximum tension stress has the lowest tension strength among specimens with two overlapped X-type flaws under uniaxial tension tests. The tension strength of the specimen with a second flaw parallel to the maximum tensionstress is the highest one among the specimens with two overlapped X-type flaws under uniaxial tension tests.