Abstract

In underground coal mining, the working face end is a bridge connecting the stope and the roadway. It not only is characterized by a large area pressure, but also faces the problems of rib spalling, roof falling, and floor heaving. In this research, a 3313 gob side entry retaining in fully mechanized top coal caving face in Shanxi Province was taken as the study object. First, by setting up stress sensors in the goaf, the soft mold filling body, and single pillars at the working face end, their stress changes were respectively monitored. It was concluded that the stress recovery process of the goaf behind the working face end is characterized by periodic step growth, and the roof above the goaf at the working face end is broken layer by layer. The simulation means of 3DEC system was subsequently used to simulate the changes in the stress and displacement of the 3313 working face end. The results demonstrate that the failure of the roof at the end of the goaf also exhibits periodicity. Finally, a thin-plate mechanics model before the first failure of the roof of the working face end was established, and the deflection distribution characteristics of the thin plate under six different length-to-width ratios were compared and analyzed. The research results of this study have important practical significance for deeply understanding the failure mechanism of the roof at the working face end and give a guarantee of the safe and efficient exploitation of coal mining.

Article Highlights

• The stress evolution of coal goaf was investigated via field measurements.

• The roof collapse and dynamic evolution of three-dimensional mining stress were investigated via numerical simulation.

• The mechanism of roof failure at the working face end was discussed.

中文翻译：

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基于采空区应力演化的工作面端部顶板破坏特征

摘要

在地下煤矿开采中，工作面端是连接采场和巷道的桥梁。它不仅具有大面积压力的特点，而且还面临肋骨剥落，屋顶塌落和地板起伏的问题。本研究以山西省综放工作面中保留的3313采空区边入口为研究对象。首先，通过在采空区，软质模具填充体和工作面端部的单个立柱上设置应力传感器，分别监视它们的应力变化。得出的结论是，采空区工作面末端后面的采空区应力恢复过程具有周期性的逐步增长特征，采空区工作面末端上方的顶板是逐层破碎的。随后，使用3DEC系统的仿真工具来仿真3313工作面端部的应力和位移的变化。结果表明，采空区末端的屋顶破坏也表现出周期性。最后，建立了工作面端部顶板首次失效之前的薄板力学模型，并比较和分析了六种不同长宽比下的薄板挠度分布特性。该研究结果对深入认识工作面端部顶板的破坏机理具有重要的现实意义，并为保证安全，有效地开采煤矿提供了保证。结果表明，采空区末端的屋顶破坏也表现出周期性。最后，建立了工作面端部顶板首次失效之前的薄板力学模型，并比较和分析了六种不同长宽比下的薄板挠度分布特性。该研究结果对深入认识工作面端部顶板的破坏机理具有重要的现实意义，并为保证安全，有效地开采煤矿提供了保证。结果表明，采空区末端的屋顶破坏也表现出周期性。最后，建立了工作面端部顶板首次失效之前的薄板力学模型，并比较和分析了六种不同长宽比下的薄板挠度分布特性。该研究结果对深入了解工作面端部顶板的破坏机理具有重要的现实意义，并为保证安全，有效地开采煤矿提供了保证。

文章重点

• 通过现场测量研究了采空区的应力演化。

• 通过数值模拟研究了三维开采应力的顶板塌陷和动态演化。

• 讨论了工作面末端顶板破坏的机理。