## 1 Introduction  
The vertical stress induced by gravity probably exceeds the compressive strength of engineering rock when the mining depth exceeds 1 km. The presence of high stress is considered as one of the most remarkable environmental characteristics during the mining of deep rock. Even an insignificant mining disturbance can trigger failure, moreover, deep rock presents mechanical properties that can be quite different from those of shallow rock. The rock undergoes brittle-ductile transition, also showing significant rheological behaviours. In addition, the failure mode varies from dynamic failure to quasi-static failure. It is quite difficult to explain the failure and deformation mechanisms of blasting on rock under high stress by applying the traditional theories of rock mechanics. When breaking rock with the aid of the drilling and blasting method in a high-stress environment, rock failure is a dynamic evolution process under the coupling effect between the geostress field and the blasting-induced stress field, during which the failure mode of the rock is complex and ever-varying. Therefore, studying failure characteristics of rock caused by blasting under high stress, the influences of different initial stress states on blasting-induced failure, and the mechanism of rock fracture under coupling of high stress and blasting is important when optimising blasting parameters and maintaining stability of the surrounding rock. Blasting with explosives is a high-temperature, high-pressure, high-speed transient process. The blasting-induced stress field is extremely complicated and rock itself shows anisotropic mechanical properties. In addition, the mechanism of rock fracture induced by blasting remains poorly understood as it is limited by current measurement techniques in such a high-temperature, high-pressure, and high-speed environment. Scholars have conducted numerous physical model and numerical simulation tests focused on the mechanism of rock fracture by blasting in recent years [1; 2; 3; 4]. In terms of physical tests, a split Hopkinson pressure bar (SHPB) test device is commonly used to explore the dynamic mechanical behaviours of rock materials under different stress regimes [5; 6; 7]. By conducting dynamic tests on rock under different confining pressures by utilising the SHPB test device, [PERSON] [8] investigated the dynamic characteristics manifest during rock failure under different initial stresses. [PERSON] [9] conducted tests on siltstone samples under different coupled static and dynamic stresses based on the improved SHPB test device and further explored the changes in rock strength under different coupled loads. By employing a self-designed static stress loading device and the improved SHPB test device, [PERSON] [10] conducted combined dynamic and static tests on sandstone samples with a pre-cut hole and further discussed the factors influencing the initiation, formation, and propagation of cracks on the surface of the samples. As for the simulation test of the blast shock arising from an explosion, [PERSON] [11] performed blasting tests on granite under different lateral pressure coefficients. He observed the process of crack propagation during blasting by using the high-speed digital image correlation (DIC) and strain measurement techniques and ascertained the trend in dynamic strain in granite under different confining pressures. [PERSON] [12] conducted blasting tests on concrete samples based on high-pressure air blasting technology and further proposed a damage model for high-pressure air blasting by observing and analysing crack distribution and particle acceleration on the surface of the model. [PERSON] [13] conducted blasting crater tests on cement mortar samples under different static-stress states and discussed the mechanism of influence of the static stress on the shape of the blasting crater by analysing the final pattern of the blasting crater and the distribution of blasting-induced cracks.