## 1 Introduction
[18; 19] abstracted the deformation process in the shear localization zone of fractured rock-like materials into two stages and then studied the influence of fissure space position on its penetration mechanism. [PERSON] et al. [20] investigated the impact of the fracture angle and distribution density on the failure of multi fractured rock materials; their findings provide insight into the change in the strength of multi fractured rock in underground engineering. [PERSON] et al. [21] conducted SHPB loading tests on sandstone with different numbers and depths of nonpersistent fissures and analyzed their dynamic failure characteristics. [PERSON] et al. [22] conducted one-dimensional impact tests on fractured and nonfractured rock specimens using an SHPB with a confining pressure chamber. The effects of confining pressure, filling material, and thickness on the stress waves were analyzed. [PERSON] et al. [23] analyzed the connection between media dynamic parameters and initial gas pressure under cyclic shock. [PERSON] et al. [24] used cement mortar to simulate rock specimens with different angles of cracks and used an SHPB device to carry out dynamic and static loading tests, respectively. [PERSON] et al. [25] performed uniaxial compression tests using an SHPB on 3D-printed rocks with prefabricated cracks of different inclinations. [PERSON] et al. [26; 27] investigated the energy mechanism of rock during deformation and failure. [PERSON] et al. [28] ran SHPB tests on jointed rock masses under seven different working conditions; they studied the relationship between their dynamic strength and joints. [PERSON] et al. [29] analyzed the effect of crack angle on the specimen's failure strength and identified the reasons for this, which underpinned the theory of practical engineering. [PERSON] et al. [30] investigated the mechanism of the coalescence of three parallel cracks in rock-like materials. [PERSON] [31] divided the cracks generated around the porous rock into three basic forms through experimental research: remote, primary, and shear cracks. [PERSON] et al. [32] conducted a systematic study on the mode of crack propagation in holed granite under compression. [PERSON] et al. [33] proposed that there is a critical compressive stress that causes an open crack to close. [PERSON] et al. [34] used a gypsum model to prefabricate cracks and carried out uniaxial and biaxial loadings under different confining pressures. [PERSON] [35] highlighted the influence of the crack length and angle on both crack initiation behavior and propagation in a uniaxial compression test of a cracked rock model. In addition, many scholars [36; 37; 38] have analyzed different aspects of crack propagation in rock specimens under varying conditions and have made great achievements. Based on the above research, discussions about fractured rock mass mainly focus on the impact of the change in fracture dip angle on the dynamic performance of rock, and we found that the previous studies mainly focused on the variation in the kinetic parameters of specimens with small fracture thicknesses (<1 mm) [39] Therefore, in this study, we chose to use 0.5 mm as a gradient, and the crack thicknesses selected were within 1.5-3.5 mm. Therefore, this article describes the use of a split Hopkinson pressure bar (SHPB) tester to perform impact compression tests on intact sandstone samples with different prefabricated crack thicknesses. The variation in the dynamic performance of prefabricated fractured sandstone specimens with fractures of different thickness was explored, and this analysis focused on the mode and mechanism of crack propagation.