Fissured rock mass is the most common construction object in geotechnical engineering and its mechanical properties are closely related to the stability of geotechnical engineering. A laboratory uniaxial compression test and a numerical simulation test were separately carried out on the fissured sandstone samples. Based on parameters, such as crack coalescence modes, the ratio of rise time to amplitude (RA) and the ratio of acoustic emission (AE) counts to duration (AF) of AE signals and spatial distribution of microcracks, failure modes and microcrack propagation laws of fissured sandstone were studied. The results demonstrate that the failure mode of fissured sandstone changes from being dominated by tensile failure into by shear failure with the increase of the dip angle of prefabricated fissures. The results of RA and AF of AE signals illustrate that it is difficult to produce tensile microcracks, but easy to generate shear microcracks in the samples with the rise of the dip angle of prefabricated fissures. In the numerical simulation test, when the dip angle of prefabricated fissures is small (θ ≤ 60°), microcracks initiate near the tip of prefabricated fissures. However, if the dip angle is large (θ ≥ 75°), the initiation location of microcrack is slightly affected by prefabricated fissures. In addition, the method for determining tensile and shear cracks was proposed based on the velocity field of particles. The results show that as the dip angle of prefabricated fissures increases, there are increasingly less tensile macrocracks, but increasingly more shear cracks at failure of the samples, which is basically consistent with conclusions obtained in the laboratory test of rock mechanics.

裂隙岩体是岩土工程中最常见的施工对象，其力学性能与岩土工程的稳定性密切相关。对裂隙砂岩样品分别进行了室内单轴压缩试验和数值模拟试验。基于参数，例如裂纹合并模式、上升时间与振幅之比 (RA) 和声发射 (AE) 计数与持续时间 (AF) 之比以及微裂纹的空间分布、失效模式和微裂纹传播规律裂隙砂岩进行了研究。结果表明，随着预制裂隙倾角的增加，裂隙砂岩的破坏模式由以拉伸破坏为主转变为以剪切破坏为主。AE信号的RA和AF结果表明，随着预制裂缝倾角的增大，试样不易产生拉伸微裂纹，但容易产生剪切微裂纹。在数值模拟试验中，当预制裂缝倾角较小时（θ  ≤ 60°），微裂纹在预制裂缝尖端附近开始。但是，如果倾角较大（θ≥75  °），则微裂纹的萌生位置受预制裂缝的影响较小。此外，提出了基于粒子速度场的拉伸和剪切裂纹确定方法。结果表明，随着预制裂隙倾角的增大，试样破坏时的拉伸宏观裂纹越来越少，而剪切裂纹越来越多，这与室内岩石力学试验得出的结论基本一致。