## 1 Introduction  
Coal is a rock mass with abnormal joint development. The geological conditions of deep coal seams have become increasingly intricate, often exhibiting defects such as unstable coal seam angles and abundant coal joints [1, 2], which make the strength and deformation characteristics of coal anisotropic [3, 4, 5]. The joint is a weak plane structure of coal, which is often mixed with inorganic minerals and other ingredients [6, 7, 8]. In terms of coal instability, the energy release, transformation law, and bursting liability are greatly affected by joints [9, 10], which brings great challenges to the safe production of coal mines. The failure of coal is accompanied by the release and transformation of energy [11]. Through uniaxial compression [12], triaxial compression [13], cyclic loading [14], and tensile failure [15] experiments, many scholars have revealed the energy release and transformation mechanism of coal rock under different failure modes and stress paths. [PERSON] et al. [16] analyzed the influence of anisotropic joints on the energy evolution, acoustic emission (AE), and fracture mode of marble and found that the degree of crack bending determines the energy release. [PERSON] et al. [17] studied the evolution of energy in coal samples at different sampling depths and found that both total energy and dissipated energy increased with increasing sampling depth. [PERSON] et al. [18] used numerical simulation methods to study the energy evolution and crack development laws of coal-rock combinations and found that the larger the height ratio of coal to rock, the faster the energy dissipation. Recently, some scholars have further analyzed the effects of strain rate, the inclination angle of coal-rockcombinations, and original cracks on the energy evolution of coal rock failure [19; 20; 21]. However, previous studies on energy evolution laws have mostly focused on intact coal rocks or rocks with joints. As a heterogeneous body with abnormal joint development, the energy release and transformation law of coal is seriously affected by the weak plane structure of joints in the process of failure. Bursting liability is a comprehensive reflection of various mechanical properties of a coal mass, i.e., its accumulated energy under a load that exceeds its bearing limit and which is suddenly released [22; 23]. [PERSON] and [PERSON] et al. [24] studied the relationship between coal microstructure and bursting liability by means of microexperiments. [PERSON] et al. [25] introduced the impact energy velocity index (\(W_{ST}\)) as an index of the bursting liability of coal and demonstrated its scientific rationality. [PERSON] et al. [26] calculated the impact kinetic energy of coal rock crushed blocks and modified the evaluation index of bursting liability by using the established criterion of impact kinetic energy. Rock burst is closely related to the stress and energy state of the coal rock mass. [PERSON] [27] carried out uniaxial and triaxial loading experiments on coal rocks and analyzed the relationship between confining pressure and the strength and deformation failure characteristics of coal rock. Rock bursts are the result of the sudden instability of a coal rock system and the rapid release of energy [28; 29; 30]. When a rock burst occurs, the roof of the coal rock will sink violently, the energy flowing into the coal body will increase rapidly, and the energy of the coal rock system will gather, dissipate, and lose balance [31; 32]. Due to the influence of joints, the mechanics of coal failure and the energy evolution are quite different. It is of certain guiding significance to study the relationship between coal burst tendency and the JIA from the perspective of energy. This paper systematically conducts uniaxial compression failure experiments on coal with JIAs of \(0^{\circ}\), \(15^{\circ}\), \(30^{\circ}\), \(45^{\circ}\), \(60^{\circ}\), \(75^{\circ}\), and \(90^{\circ}\), analyzing the energy evolution law of coal failure with different JIAs.