The mechanism and fracture aperture of thick hard roof failure were theoretically analyzed from the perspective of elastoplastic mechanics. A uniform load cantilever beam was established by considering the voussoir beam structure and stress condition. According to the stress inverse principle in solving the plane strain problem, the internal stress component analytic solution was deduced. Considering the lateral thrust and shear force and by applying the Mohr‐Coulomb failure criterion, the plastic zone boundary equation was obtained. Further analysis of the equivalent stress, equivalent strain, elastic energy density, distortion energy density, and strain energy density was studied with blocks of four different lengths, combined with the rotation angles after failure, to analyze the fissure aperture between straight and curved fracture traces. The theoretical analysis reveals that the deviatoric effect plays the lead role in rupture initiation and propagation; the cracks will deflect during failure, and the fracture trace presents a curved shape. The variation of fracture aperture exhibits a tendency to increase first, then decrease, and then increase along the fracture trace. The analytical approach presented in this paper provides a theoretical basis for determining the main seepage channel flow in underground mining.

中文翻译：

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长壁煤层中厚壁主厚壁的Voussoir梁结构破坏机理及裂隙特征

从弹塑性力学的角度理论分析了厚硬顶板破坏的机理和裂隙孔径。考虑了悬臂梁的结构和受力情况，建立了均布的悬臂梁。根据求解平面应变问题的逆应力原理，推导了内应力分量解析解。考虑横向推力和剪力，并应用莫尔-库仑破坏准则，得出塑性区边界方程。用四个不同长度的块进一步研究了等效应力，等效应变，弹性能密度，变形能密度和应变能密度，并结合了失效后的旋转角度，以分析直缝和弯曲缝迹之间的裂隙孔径。理论分析表明，偏斜效应在破裂的发生和传播中起主导作用。裂纹将在破坏过程中发生挠曲，并且断裂痕迹呈现出弯曲的形状。裂缝孔径的变化具有沿裂缝迹线先增大然后减小然后增大的趋势。本文提出的分析方法为确定地下采矿的主要渗流通道流量提供了理论基础。