Deformation mechanism and roof pre-splitting control technology of gob-side entry in thick hard main roof full-mechanized longwall caving panel

厚硬基本顶综放工作面沿空巷道的变形机理及顶板预裂控制技术研究

This paper explores the deformation mechanism and control technology of roof pre-splitting for gob-side entries in hard roof full-mechanized longwall caving panel(LTCC).The investigation utilizes a comprehensive approach that integrates field monitoring,theoretical analysis,and numerical simulation.Theoretical analysis has illuminated the influence of the length of the lateral cantilever beam of the main roof(LCBM)above the roadway on the stability of the gob-side entry behind the panel.Numerical simulations have further revealed that the longer LCBM results in heightened vertical stress within the coal pillar,developed cracks around the roadway,and more pronounced damage to the roadway.Moreover,numerical simulations also demonstrate the potential of roof pre-splitting technology in optimizing the fracture position of the hard roof.This technology significantly reduces the length of the LCBM,thereby alleviating stress concentration in the coal pillars and integrated coal rib while minimizing the destruction of the gob-side entry.Therefore,this manuscript first proposes the use of roof pre-splitting technology to control roadway deformation,and automatically retain the entry within a hard roof LTCC panel.Field implementation has demonstrated that the proposed automatically retained entry by roof pre-splitting technology effectively reduces gob-side entry deformation and achieves automatically retained entry.

本文采用现场监测、理论分析和数值模拟相结合的方法,研究了厚硬基本顶综放工作面沿空巷道的变形机理及顶板预裂控制技术。理论分析表明巷道上方基本顶侧向悬臂梁的长度会影响到工作面后方沿空巷道的稳定性。数值模拟进一步表明,基本顶侧向悬臂梁越长,煤柱内的垂直应力越大,巷道周围裂缝越发育,巷道围岩损伤越明显。另外,数值模拟还证明了顶板预裂技术在优化坚硬顶板断裂位置方面的潜力。该技术可以显著缩短基本顶侧向悬臂梁的长度,从而减轻煤柱和实体煤帮的应力集中,同时最大限度地减少了沿空巷道的破坏。因此,本文首先提出在厚硬基本顶综放工作面使用顶板预裂技术来控制巷道变形,并自动留巷。现场应用表明,本文所提出的顶板预裂自动留巷技术可以有效减少沿空巷道的变形,并实现自动留巷。