# Study on Dynamic Loading Characteristics of Rock Containing Holes
## 1 Introduction  
The increasing demand for resources has led to deeper mining operations, which encounter greater challenges and more frequent dynamic disasters, such as rockbursts [1; 2]. These incidents are notable for their suddenness and high destructive potential [3; 4; 5; 6; 7], significantly hindering the progress of scientific and efficient practices in deep coal mining. Current strategies emphasize early warning systems and rock mass control technologies to counteract these events. Early warning mechanisms deploy a variety of monitoring techniques to assess potential risks, incorporating methods such as drill cuttings analysis, deformation monitoring, microseismic (MS) monitoring [8; 9; 10; 11], and advanced seismic wave speed imaging [12; 13], alongside acoustic emission (AE) and electromagnetic radiation (EMR) technologies [14; 15]. The synergy of these methods enhances the predictive capabilities for rockburst occurrences. Meanwhile, rock mass control involves strategies like local pressure relief [16; 17; 18; 19; 20] and reinforcement of the surrounding rock [21; 22]. Among these, borehole pressure relief technology [23; 24; 25] is particularly effective in stress redistribution within coal and rock masses in high-stress areas, due to its quick results, cost-effectiveness, and ease of application. This technology is especially beneficial in preventing deformations in rock masses in areas vulnerable to rockbursts. Given the complex on-site conditions and the need to minimize operational disruptions, research on borehole pressure relief technology often begins with controlled indoor experiments to validate its effectiveness before proceeding to field engineering tests. This method has prompted many scholars to study the dynamic cracking processes, failuremechanisms, and mechanical properties of rocks under borehole pressure relief through experimental investigation. For example, [PERSON] et al. [26] explored the correlation between borehole parameters and rock mechanical properties, deducing that enlarging sections and reducing the spacing between holes can mitigate the formation of lateral fractures, thereby lowering the risk of slabbing in practical applications. Similarly, [PERSON] et al. [27] examined the impact of random and structured hole distributions on crack initiation, coalescence, and the failure patterns of rock materials, subsequently suggesting a criterion based on hole distribution. Furthermore, [PERSON] et al. [28] assessed the efficacy of boreholes with varying diameters compared to those with uniform diameters, revealing that boreholes with fluctuating diameters significantly enhance pressure relief more effectively than uniform diameter boreholes with the same maximum diameter. This research significantly advances our understanding of damage in flawed rock materials, proving to be a crucial asset for engineering applications. With technological progress, the Split Hopkinson Pressure Bar (SHPB) method has become the preferred technique for studying rock materials' mechanical behavior and fracture mechanisms at high strain rates. Many scholars [29; 30; 31; 32] have applied SHPB technology to investigate the mechanical characteristics of flawed rocks. For instance, [PERSON] et al. [33] performed dynamic impact tests on flawed rock materials to discern the variance in degradation mechanisms under quasi-static loading conditions. Similarly, [PERSON] et al. [34] analyzed the dynamic failure modes of rocks with single and double flaws, identifying nine distinct fracture types that occur during the failure process of rocks. Moreover, [PERSON] et al. [35], among others, utilized SHPB experiments to study rock materials under various loading conditions, demonstrating a distinct dependence of mechanical response and cracking mechanisms on strain rate. Additionally, [PERSON] et al. [36; 37; 38] found that rock specimens with cavities tend to exhibit shear fractures at high impact velocities, while tensile fractures are more common at lower velocities.