胶结充填采场顶板承载特性及煤柱稳定性分析

为研究连采连充式胶结充填采场顶板承载特性及煤柱稳定性,基于FLAC3D建立数值模型,分析了顶板交替承载特性,研究了顶板主次承载结构的转换规律,揭示了煤柱应力释放及变形规律。基于煤柱两侧约束条件的差异性,建立了煤柱应力分布的力学模型,得到了应力集中系数、临时支护强度、埋深等因素对煤柱极限承载宽度的影响规律。通过煤柱与充填体协同承载的数值模拟,揭示了充填体宽度对煤柱承载特性的影响规律。结果表明:采场顶板承载结构随工作面推进而变换,且在煤柱与充填体协同承载阶段,煤柱为主要承载结构,随煤柱的逐步采出,充填体逐步过渡为主要承载结构;煤柱应力平衡区宽度与临时支护强度呈反比,且与工作面埋深和应力集中系数呈正比,提高临时支护强度,能显著降低临空面破碎区范围,减小极限平衡宽度;增加充填体宽度可保障煤柱稳定。在昊源煤矿中,通过提高充填体强度与充填率,提高充填体对煤柱的约束效应,有效保障了煤柱稳定性,为类似条件下煤柱变形控制提供参考。

Analysis of roof bearing characteristics and coal pillar stability of cemented backfill field

In order to study the bearing characteristics of the roof and the coal pillar stability of continuous mining and continuous filling cemented filling field, a numerical analysis model based on FLAC3D is established to analyse the alternate bearing characteristics of the roof, study the conversion law of the primary and secondary bearing structures of the roof, and reveal the stress release and deformation law of the coal pillar. Based on the difference of the constraint conditions on both sides of the coal pillar, a mechanical model of the stress distribution of the coal pillar is established, and the influence law of the stress concentration coefficient, temporary support strength, burial depth and other factors on the ultimate bearing width of the coal pillar is obtained.By establishing the numerical analysis and simulation of the synergistic bearing of coal pillar and filler, the influence of the width of filler on the bearing characteristics of coal pillar is revealed. The study shows that: the bearing structure of the mine roof changes with the advancement of the working face, and the coal pillar is the main bearing structure during the co-bearing stage of the coal pillar and the filling body, and the filling body gradually transitions to the main bearing structure as the coal pillar is gradually extracted; the width of the stress equilibrium zone of the coal pillar is inversely proportional to the strength of the temporary support, and is positively proportional to the burial depth of the working face and the stress concentration coefficient, increasing the strength of the temporary support can significantly reduce the fragmentation zone of the critical surface. The increase in the width of the filling body can effectively control the stability of the coal pillar, and its main function is to reduce the force on the coal pillar while playing a role in restraining the lateral deformation of the coal pillar. In Haoyuan coal mine, by increasing the strength and filling rate of the filling body and enhancing the restraining effect of the filling body on the coal pillar, the stability of the coal pillar is effectively guaranteed, which provides a reference for the control of coal pillar deformation under similar conditions.