Sandstone samples with precracks of different dip angles were collected from a coal mine roof and subjected to uniaxial compression tests, and acoustic emission (AE) and scanning electron microscopy (SEM) were used to study how the crack dip angle affected the fracture mechanism. In the precracked sandstone samples, as the dip angle between the crack line and loading direction decreased, so did the peak stress and its completion time. The SEM observations revealed a fracture transition from tensile cleavage to shear slip, which was manifested by a microstructure change from aggregate to staggered. According to energy conversion, a decreased crack dip angle results in gradually decreasing total and dissipative peak energies, whose variation amplitudes at different stages are consistent with those of the peak stress of the samples. The decreased crack dip angle lowered the stress required to trigger the first appearance of AE energy peaks and ring-down counts, as well as shortening the period before the occurrence of the first AE peak signal. However, the AE energy and ring-down count during the failure stage after the stress peak increased gradually. A stepped increase was observed in the AE ring-down count curves, with each step corresponding to a jump in the stress-strain curve. From the characteristics of the AE signal of the fracture of a precracked rock sample, the occurrence of joints or faults in the rock mass can be reasonably inferred. This is expected to provide a new method and approach for predicting coal and rock dynamic disasters.

从煤矿井​​顶收集了具有不同倾角的裂缝的砂岩样品，并进行了单轴压缩试验，并使用声发射（AE）和扫描电子显微镜（SEM）研究了裂缝倾角如何影响断裂机理。在预裂砂岩样品中，随着裂纹线和加载方向之间的倾角减小，峰值应力及其完成时间也随之减小。SEM观察表明，断裂从拉伸解理过渡到剪切滑移，其微观结构从骨料转变为交错状。根据能量转换，减小的裂纹倾角会导致总的和耗散的峰值能量逐渐减小，其在不同阶段的变化幅度与样品的峰值应力相一致。减小的裂纹倾角降低了触发AE能量峰的首次出现和振铃次数所需的应力，并缩短了出现第一个AE峰信号之前的时间。但是，在应力峰值之后的失效阶段，AE能量和振铃次数逐渐增加。在AE衰荡计数曲线中观察到逐步增加，每一步对应于应力应变曲线的跳跃。从预裂岩石样品断裂的AE信号的特征，可以合理地推断出岩体中节理或断层的发生。有望为预测煤炭和岩石动态灾害提供一种新的方法和方法。以及缩短出现第一个AE峰值信号之前的时间。但是，在应力峰值之后的失效阶段，AE能量和振铃次数逐渐增加。在AE衰荡计数曲线中观察到逐步增加，每一步对应于应力应变曲线的跳跃。从预裂岩石样品断裂的AE信号特征可以合理地推断出岩体中节理或断层的发生。有望为预测煤炭和岩石动态灾害提供一种新的方法和方法。以及缩短出现第一个AE峰值信号之前的时间。但是，在应力峰值之后的失效阶段，AE能量和振铃次数逐渐增加。在AE衰荡计数曲线中观察到逐步增加，每一步对应于应力应变曲线的跳跃。从预裂岩石样品断裂的AE信号的特征，可以合理地推断出岩体中节理或断层的发生。有望为预测煤炭和岩石动态灾害提供一种新的方法和方法。每个步骤都对应于应力-应变曲线的跳跃。从预裂岩石样品断裂的AE信号特征可以合理地推断出岩体中节理或断层的发生。有望为预测煤炭和岩石动态灾害提供一种新的方法和方法。每个步骤都对应于应力-应变曲线的跳跃。从预裂岩石样品断裂的AE信号的特征，可以合理地推断出岩体中节理或断层的发生。有望为预测煤炭和岩石动态灾害提供一种新的方法和方法。