松动圈理论在近距离煤巷支护设计中的应用

针对晋华宫矿14#层5705巷这一近距离煤巷支护困难的问题,利用钻孔摄像仪对其松动圈分布情况进行了实测,分析研究了现有支护方案存在的问题。基于松动圈支护理论进行了设计,通过在巷道顶角施加角锚杆,减小作用在剪切面上的剪应力,增加剪切面上的正应力,抑制了顶角剪切破坏的出现,增强了支护的整体性。实践结果表明,巷道开挖22 m后达到稳定状态,两帮收敛15.3mm,顶板下沉量8.0 mm,没有明显的底鼓,取得了良好的支护效果。

近距离煤层煤巷掘进底板防突岩柱厚度数值分析

以平煤股份五矿己-1532020掘进工作面为研究对象,针对该掘进工作面处于近距离煤层上保护层内、掘进巷道底板与被保护层的间距过小、掘进过程中可能发生下部突出煤层冲破底板岩柱而导致煤与瓦斯突出的情况,运用FLAC3D对底板防突岩柱厚度进行模拟研究,结果表明,在围岩均质完整情况下,煤巷掘进的最小预留防突岩柱厚度不应小于2.5 m,结合现场实际,安全岩柱厚度应不小于3 m。

Entry roof truss-bolt system test under the gob of contiguous seams

Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2 seam. The No.9 and No.10-2 seams are contiguous seams. The No.9 seam has been mined out and the No.10-2 seam will be mined under the gob of the No.9 seam. The roof strata of the No.10-2 seam may have been weakened and fractured due to the shear failure caused by the No.9 seam mining activities. The steel beam sets spaced at 0.8 m have been used to support the entry of the No.10-2 seam. In order to speed up the advance rate and cut entry development cost, a test area, using roof bolt in conjunction with truss-system, was successfully conducted. This paper presents the support system design, application of designed system, and the test results. Test results provide a cheaper, quicker, and safer way to support entry for the No.10-2 seam.