煤的层理面倾角(bedding plane angles ,BDA)对射流破岩的效果影响显著。为探讨真三轴应力下不同层理面倾角煤的射流破坏机制，开展了不同层理面倾角煤在真三轴应力下的纯水射流冲蚀实验。结果表明，煤在层理面倾角较低和较高时，射流冲击分别容易形成锥形破碎坑和裂缝坑，破碎坑开口随着层理面倾角的增大由圆形逐步向椭圆形过渡，煤的破坏模式由剪切破坏主导转变为拉伸-水楔效应主导。随着层理面倾角增至60°，破岩体积增加了154.35%。当施加三轴应力时，层理面对射流破煤性能的影响被抑制，不同层理面倾角煤的破坏模式仅呈现圆孔破碎坑，水锤压力引起的剪切破坏是煤在三轴应力下破坏的主要原因，60°层理面倾角煤的破坏体积减少了95.6%，相比其他倾角降低幅度达到最大。层理面倾角对煤的轴向损伤演化具有驱动作用，随着倾角增大，轴向损伤发生波动。当施加三轴应力时，三轴应力抑制了射流破煤的损伤演化，煤的轴向损伤出现收缩。煤的破碎坑壁面的扫描电子显微镜（scanning electron microscope,SEM）结果表明：当施加三轴应力时，0°层理面倾角煤的破碎孔壁不再出现微裂隙与脆性剪切破坏的痕迹，并且孔隙的数量与尺寸大幅减小；60°层理面倾角煤的破碎孔壁不再出现由于水楔作用导致的大量锯齿状痕迹，三轴应力下不同层理面倾角煤的破碎孔壁面均出现明显的延性剪切破坏特征。

The angle of coal’s bedding planes significantly affects the performance of jetting in rock fracturing. To investigate the mechanism of failure and damage characteristics of coal with different bedding plane angles (BDA) under true triaxial stress conditions, erosion experiments using pure water jets were conducted at various BDA and triaxial stress levels. The experimental results indicate that the angle of coal’s bedding planes has a pronounced impact on the fracturing capacity of the water jet. For coal samples with lower and higher BDA, the water jet impact tends to form cone-shaped erosion pits and crack-like pits, respectively. Additionally, the opening of the erosion pits transitions from circular to elliptical as the BDA increases, and the failure mode shifts from shear-dominated to water-wedge effect-dominated. With the increase in coal’s BDA, the fracturing performance improves by 154.35%, reaching its peak when the BDA is 60°. As the BDA of coal increases, the orifice of the broken pit transitions from circular to elliptical. Under the application of triaxial stress, the destruction of coal samples with various BDA only presents circular erosion pits, and the shear damage caused by water hammer pressure becomes the primary reason for the failure of coal samples under triaxial stress. The difference in jetting damage among samples with different BDA is significantly reduced, and the influence of coal’s bedding planes on the fracturing capacity of the water jet is significantly weakened. The reduction in the fracturing volume of 60 BDA samples reaches 95.6%, the maximum decrease observed. CT scan results reveal that the tension damage caused by the water wedge effect is the primary factor affecting the failure characteristics, with the most severe impact at 60 BDA, and the area of jet damage decreases with the increase in triaxial stress. Scanning electron microscope(SEM） results indicate that triaxial stress causes the closure of pre-existing cracks and micro-damage in coal samples with different BDA, promoting a transformation from brittle shear failure to ductile shear failure in the pit wall of 0 BDA coal samples, and significantly reducing the water wedge effect in 60 BDA coal samples, shifting towards shear failure.