Controlled blasting technology is an effective way to enhance coalbed methane recovery, but the theoretical research has fallen behind engineering practice seriously. Therefore, in this work, based on the damage and fracture mechanics theory, the coal damage process and mechanism under the multiple actions of the blasting stress wave (BSW) were analyzed firstly. Then, the simulation experiment of coal damage accumulation was designed and carried out; during the experiment, the ultrasonic velocity of the samples was measured and the damage values were calculated. Under the multiple actions of BSW, the initial radial cracks around the blast-hole wall or in the area near the explosion source are formed under the action of tangential tension of BSW and the internal pressure of the blast-hole, and under the combined actions of stress wave, gas, and in situ stress, the primary cracks in the middle and far area of the explosion source expand and form the mesoscopic cracks because of the damage accumulation at the crack tip. And then the mesoscopic cracks grow and intersect to form a macroscopic crack. Finally, the macroscopic cracks expand and intersect with the initial radial cracks, the samples break suddenly under the load far below their fracture toughness because of the damage accumulation effects. Hence, the research results have guiding significance for better understanding and application of controlled blasting technology to enhance the CBM recovery.

控制爆破技术是提高煤层气采收率的有效途径，但理论研究严重落后于工程实践。因此，在这项工作中，基于破坏和断裂力学理论，首先分析了在爆炸应力波（BSW）的多重作用下的煤破坏过程和机理。然后设计并进行了煤害累积模拟实验。在实验过程中，测量样品的超声速度并计算损伤值。在BSW的多重作用下，在BSW的切向张力和爆破孔的内部压力的作用下，在爆破孔壁周围或爆炸源附近的区域中形成了初始径向裂纹。应力波，气体，在现场应力作用下，由于裂纹尖端处的损伤积累，爆炸源中远处的一次裂纹扩展并形成了介观裂纹。然后，介观裂纹扩展并相交形成宏观裂纹。最后，宏观裂纹扩展并与初始径向裂纹相交，由于破坏累积效应，样品在远低于其断裂韧性的载荷下突然断裂。因此，研究结果对更好地理解和应用控制爆破技术以提高煤层气采收率具有指导意义。然后，介观裂纹扩展并相交形成宏观裂纹。最后，宏观裂纹扩展并与初始径向裂纹相交，由于破坏累积效应，样品在远低于其断裂韧性的载荷下突然断裂。因此，研究结果对更好地理解和应用控制爆破技术以提高煤层气采收率具有指导意义。然后，介观裂纹扩展并相交形成宏观裂纹。最后，宏观裂纹扩展并与初始径向裂纹相交，由于破坏累积效应，样品在远低于其断裂韧性的载荷下突然断裂。因此，研究结果对更好地理解和应用控制爆破技术以提高煤层气采收率具有指导意义。