Cylindrical sandstone specimens with same crack lengths and different crack inclinations (β) were subjected to direct tensile testing (DTT) and uniaxial compression testing (UCT) in a laboratory. Meanwhile, the acoustic emission signals, mechanical and acoustic characteristics, numerical simulation results and the failure modes of the specimens were analyzed. The test results showed that the existence of cracks had a weak effect on the strength of the specimens during DTT/UCT, while the strengths of the specimens increased gradually with β. Further, the elastic modulus of rock gradually increased with an increase in β during UCT, while it was almost unchanged during DTT. The ultimate strain of all the specimens gradually increased with β. For all specimens, mode-Ⅰ cracking was initiated at the tip of the pre-existing crack during DTT; finally, tensile failure was observed. There is a certain difference between the initiation angle obtained in the test results and the theoretical value derived using the maximum hoop stress theory. The specimen theoretically exhibited mode-Ⅰ crack initiation when β ∈ [60°~90°] during UCT, while demonstrating mode-Ⅱ crack initiation at other β values; however, the experimental crack initiation angle was different from the theoretical value that fulfills the plane fracture criterion. The acoustic emission (AE) event only occurred when the specimen was critically damaged during DTT; the entire process from the initiation of the crack to the instability failure of the specimen occurs within a short time. Meanwhile, the AE signal accompanied the entire loading process during UCT, which can clearly distinguish the crack initiation stress of the specimens. In addition, the simulation results of the fracture characteristics of the specimens and the experimental results are in general agreement.

在实验室中对具有相同裂纹长度和不同裂纹倾角（β）的圆柱形砂岩试样进行直接拉伸试验（DTT）和单轴压缩试验（UCT）。同时，对试件的声发射信号、力学和声学特性、数值模拟结果和破坏模式进行了分析。试验结果表明，裂纹的存在对 DTT/UCT 试件的强度影响较弱，而试件的强度随着β 的增大而逐渐增大。此外，岩石的弹性模量在 UCT 期间随着β的增加而逐渐增加，而在 DTT 期间几乎没有变化。所有试件的极限应变均随β逐渐增大. 对于所有试件，在 DTT 过程中，I 型裂纹发生在预先存在的裂纹尖端；最后，观察到拉伸破坏。试验结果得到的起爆角与采用最大环向应力理论推导出的理论值存在一定差异。试样表现出理论上模式-Ⅰ裂纹萌生当β  ＆Element; [60°〜90°] UCT期间，同时展现模式-Ⅱ裂纹在其它起始β价值观；然而，实验裂纹起始角与满足平面断裂准则的理论值不同。声发射 (AE) 事件仅在 DTT 期间试样严重损坏时发生；从裂纹萌生到试件失稳破坏的整个过程都在短时间内发生。同时，在UCT过程中，AE信号伴随着整个加载过程，可以清楚地区分试件的裂纹萌生应力。此外，试件断裂特性的模拟结果与实验结果基本吻合。