针对承压水体上安全采煤，为进一步认识工作面底板岩层的破坏机理，运用断裂力学理论，并结合Griffith破坏准则分析工作面端部屈服区破坏范围。在此基础上运用滑移线场理论建立底板塑性区破坏力学模型，给出底板最大破坏深度及其塑性区分布范围的理论求解方法，并分析了底板最大破坏深度与其影响因素的关系，为承压水体上开采底板突水防治提供理论依据。最后，通过工程应用实例，验证了理论计算方法的可行性。

To further understand the failure mechanism of mining face floor in the case of coal mining above confined aquifer, the scope of plastic failure in the yield zone of mining face was analyzed by using fracture mechanics theory and Griffith criterion. On this basis, the mechanical model of the plastic failure scope of mining floor was established in line with the slip-line field theory. A theoretical solution for the plastic failure scope and the maximum floor damage depth was given by the model. The relationship between the maximum depth of broken floor and its affecting factors was analyzed. It could provide a theoretical basis for preventing water inrush above a confined aquifer. Finally, the theoretical solution was proved to be feasible by an engineering application example.