The weak bedding sandwiched between rock layers is one of the crucial factors influencing the overburden failure with the extraction of coal resources in longwall mining. In this article, the physical model tests and discrete element modelling (DEM) were carried out to examine the effects of bedding adhesion strength (BAS) on the roof fracture with longwall coal mining. A novel model generation method in the universal distinct element code was proposed for the investigation of a propagating crack interaction with existing discontinuities. It is found that crack trajectory changes from deflection to penetration with the strength increase of a discontinuity. The stair-stepping fracture of overburden cantilever structure is more prominent for the rock layers with weaker BAS, which is in coincidence with the triangular block-based DEM result. Moreover, the mechanism of failure pattern influenced by BAS was clarified by the cantilever beam theory and fracture criterion of crack competition. With the outcomes above, the longwall coal mining-induced stratified roof fracture characteristics in engineering scale were revealed. Three quantitative regions were divided in terms of the strength ratio between bedding and rock layer. Finally, three aspects, the heights of the caved zone and fractured zone, the subsidence of ground surface, and the abutment pressure of roof affected by the BAS were discussed, respectively, with some suggestions recommended for the stability controlling of roof and safety production of coal mining.

夹在岩石层之间的弱层理是长壁开采煤炭资源开采中影响上覆破坏的关键因素之一。在本文中，进行了物理模型测试和离散元建模（DEM），以研究层状粘结强度（BAS）对长壁采煤顶板裂缝的影响。提出了一种新的通用离散元代码模型生成方法，以研究与现有不连续性的扩展裂纹相互作用。发现随着不连续强度的增加，裂纹的轨迹从挠曲变为穿透。对于BAS较弱的岩层，上覆悬臂结构的阶梯状断裂更为突出，这与基于三角形块的DEM结果吻合。而且，通过悬臂梁理论和裂纹竞争的断裂准则，阐明了BAS对失效模式的影响机理。根据以上结果，揭示了在工程规模上长壁采煤引起的分层顶板破裂特征。根据层理与岩石层之间的强度比划分了三个定量区域。最后，分别从BAS影响下的塌陷带，裂隙带高度，地表沉陷，顶板支座压力三个方面进行了探讨，并为控制顶板的稳定性和安全生产提出了一些建议。采煤。在工程规模上揭示了长壁开采引起的分层顶板破裂特征。根据层理与岩石层之间的强度比划分了三个定量区域。最后，分别从BAS影响下的塌陷带，裂隙带高度，地表沉陷，顶板支座压力三个方面进行了探讨，并为控制顶板的稳定性和安全生产提出了一些建议。采煤。在工程规模上揭示了长壁开采引起的分层顶板破裂特征。根据层理与岩石层之间的强度比划分了三个定量区域。最后，分别从BAS影响下的塌陷带，裂隙带高度，地表沉陷，顶板支座压力三个方面进行了探讨，并为控制顶板的稳定性和安全生产提出了一些建议。采煤。