含软弱结构面石灰岩巴西劈裂破坏模式研究

以湖北省秭归县某矿山石灰岩为研究对象,进行了不同软弱结构面倾角θ的巴西劈裂实验,研究了石灰岩中软弱结构面倾角对岩石试样破坏模式的影响,并探讨了相应的破坏机理。结果表明:软弱结构面对试样的劈裂破坏模式具有控制性作用,随着结构面倾角增大(0°～90°范围内),试样破坏模式可分为4种,其中,θ为0°和15°时为岩石基质以及结构面拉裂破坏,θ为30°时为岩石基质的拉裂破坏以及结构面的拉裂和滑移破坏,θ为45°和60°时为结构面的剪切滑移破坏,θ为90°时为结构面的拉裂破坏;同时发现,当θ为45°、60°和90°时,结构面对试样破坏机理的影响与层理面类似,而当θ为0°、15°和30°时,试样的破坏机理会更为复杂。

Failure Modes in Brazilian Splitting Test on Limestone with Weak Structural Planes

Brazilian splitting tests were conducted for the limestone of a mine in Zigui County of Hubei Province. The limestone with weak structural planes at different inclination angles (θ) was respectively tested to investigate the effect of different inclination angle of weak structural planes in limestone on rock failure modes. And the corresponding rock failure mechanism was discussed. The results show that the failure modes of specimens are dependent on the weak structural planes. With the increase of inclination angles of structural planes in the range of 0°～90°, the failure modes of specimens can be classified into 4 types. Tensile failure of matrix and structural plane occurs in the specimens with the inclination angle θ =0° and 15°; tensile failure of the matrix, tensile and shear slip of structural plane occur in the specimens with θ=30°; shear slip of structural plane occurs in the specimens with θ=45° and 60°; tensile failure of structural plane occurs in the specimens with θ=90°. Besides, it is found that when θ=45°, 60° and 90°, the failure mechanism of the specimens caused by the structural planes is similar to that by bedding planes, but when θ=0°, 15° and 30°, the failure mechanism will be more complex.