单轴压缩荷载下“十字形”交叉裂隙类岩石试件的破坏模式与力学特性试验研究

Experimental study on failure modes and mechanical properties of crisscross fractured rock samples under uniaxial compression conditions

通过在类岩石材料中预制特定裂隙的方法,来模拟含“十字形”交叉裂隙的岩体,并对其在单轴压缩情况下的力学特性与破坏模式进行了试验研究。研究表明:(1)交叉裂隙试件中,次裂隙倾角对主裂隙倾角为45°时试件的抗压强度与起裂应力的影响最大,而对主裂隙倾角为90°时的影响最小。(2)单裂隙试件的抗压强度与起裂应力小于完整试件。交叉裂隙试件相对于单裂隙试件而言,当主裂隙倾角为0°和45°时,其抗压强度与起裂应力减小;当主裂隙倾角为90°时,其抗压强度与起裂应力增大。(3)在单裂隙试件中,当裂隙倾角为0°、45°和90°时,试件分别发生拉剪复合型破坏、剪切破坏和张拉破坏;相对于单裂隙试件而言,交叉裂隙试件破坏时产生的裂纹相对较多,破坏模式大多为拉剪复合型破坏,同时,在破坏过程中交叉裂隙试件发生复合其他破坏模式或直接导致试件破坏的滑移。上述结果对岩体工程的开挖和建设具有一定的参考价值。

The crisscross fractured rocks are simulated by means of prefabricating specific fractures in rock-like materials.The mechanical properties and failure modes are studied experimentally under uniaxial compression conditions.The results show that:(1)Among the cross fractured rocks,the secondary crack dip angle has the greatest influence on the compressive strength and crack initiation stress when the main fractured inclination angle is 45°,while the secondary crack dip angle has the least influence on the compressive strength and crack initiation stress when it is 90°.(2)The compressive strength and the crack initiation stress of single fractured rocks are smaller than those of complete rocks.Compared with the single fractured rock,the compressive strength and the crack initiation stress decrease when the inclination angle of the main fractured inclination angle is 0°and 45°,while the compressive strength and the initiation stress increase when it is 90°.(3)In the single fractured rocks,when the main fractured inclination angle is 0°,45°and 90°,the tensile shear failure,shear failure and tensile failure occur,respectively.Compared with the single fractured rocks,the cross fractured rocks produce much more cracks when they are destroyed,and the failure mode is mostly tensile and shear composite failure.At the same time,in the process of failure,the slip of composite other failure modes or the slip of the rock directly leading to the failure of the cross fissure rock will occur.The work would provide valuable guidance for excavation and construction of rock mass engineering.