考虑水力化破煤增透措施存在一定技术漏洞以及适用条件制约了水力化措施的发展，利用磨料空气射流破煤增透可以弥补水力化措施的不足。 为了明确加载围压对磨料空气射流 破煤深度的影响，首先在分析围压对压痕力作用效果影响的基础上，将压痕断裂理论推广至围 压条件下的压痕断裂理论，再利用推广后的理论，建立磨料与靶体参数-压痕力-压痕大小-横向 裂纹大小和深度-撞击坑的大小和深度之间的因果关系，然后考虑围压对压痕大小的影响以及 压痕与煤体撞击坑深度的关系，建立破煤深度模型，进行压痕测试、撞击坑形貌测试以及破煤深 度测试实验，对建立的模型进行验证。 结果表明，加载围压:一方面减小煤体的弹性变形，使相 同压痕力造成的压痕变小;另一方面由于压痕面的存在使得压痕面对磨料产生一个向上的作用 力，减弱压痕力的作用，使压痕大小进一步减小。 压痕的减小则导致撞击坑变小;围压对破煤深 度影响是通过减小每一个磨料颗粒的撞击效果实现;加载围压越大，煤体形成的压痕和撞击坑 越小，以至于形成较小的表面形貌粗糙度，同时形成了较小的破煤深度和质量损失。 建立的破煤 深度模型，可利用未加载围压煤体的破煤深度，较为准确地计算不同围压条件下的磨料空气射流破 煤深度。

Some technical problems and narrow scope of application restrict the development of hydraulic measures to increase coal permeability，however，the abrasive air jet can mitigate the shortcomings of hydraulic measures. In or⁃ der to understand the influence of confining pressure on the coal⁃breaking depth of abrasive air jet，a new indentation fracture theory with confining pressure was proposed based on the analysis of the effect of confining pressure on inden⁃ tation force. With this new indentation fracture theory，the sequential causal relationship among abrasive and target pa⁃ rameters⁃indentation force⁃indentation size⁃transverse crack depth⁃depth of impact crater was established. Also，a model of coal breaking depth was established by considering the influence of confining pressure on indentation size and the relationship between indentation and depth of impact crater. Finally，indentation test，impact crater morpholo⁃ gy test and coal breaking depth test were carried out to verify the established model. The results show that，on the one hand，the loading confining pressure reduces the elastic deformation of coal and makes the indentation caused by the same indentation force smaller. On the other hand，the loading confining pressure makes the indentation face produce an upward force due to the existence of indentation surface，which weakens the effect of indentation force and further reduces the size of indentation. The reduction of indentation leads to the smaller size of impact crater. The effect of confining pressure on coal breaking depth is achieved by reducing the impact effect of each abrasive particle. Larger confining pressure leads to smaller indentation on coal body，less undulation on surface morphology of impact crater，shallower coal breaking depth and less quality loss. The coal breaking depth model established in this paper can accurately calculate the coal breaking depth under different confining pressure conditions， by using the depth impact crater of coal without confining pressure.