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中厚煤层切顶卸压无煤柱自成巷技术关键参数研究

Study on key parameters of self-formed roadway without coal pillar by roof cutting and pressure relief in medium and thick coal seam

  • 摘要: 现阶段切顶卸压无煤柱自成巷开采技术在薄煤层条件下应用较多,而对于中厚煤层的应用研究较少。为提高煤炭资源采出率,同时为避免以传统充填手段实现沿空留巷导致充填体位置产生应力集中,以切顶短壁梁为理论基础,以西山煤电集团公司杜儿坪煤矿62711工作面为工程背景,分析了切顶卸压无煤柱自成巷开采技术在中厚煤层的工艺流程及关键技术参数。通过理论分析和数值模拟的方法,分别对传统长壁式采煤法及切顶预裂爆破高度为4、6、8 m及切顶角度为5°、10°、15°、20°时巷道围岩应力分布及顶板位移情况进行了分析,结果表明:在合理的预裂爆破切顶高度和切顶角度条件下,不仅可以迫使顶板岩层在工作面回采后及时垮落并充满采空区,还可以有效切断巷道与采空区顶板岩层之间的应力传递路径,使得应力集中区域向实体煤深处转移,改善巷道围岩所处的应力环境,起到切顶卸压的作用。

     

    Abstract: Currently, the mining technology of self-formed roadway without coal pillars for roof cutting and pressure relief is widely used in the thin coal seam, and most of the related researches are carried out around the application in the thin coal seam, while the research of application in the medium-thick coal seam is less. In order to improve the recovery rate of coal resources and avoid the stress concentration problem caused by the filling body position caused by the traditional filling method to achieve gob-side entry retained, the short-wall beam with the top cut was used as the theoretical basis. Taking the No.62711 working face of the Du′erping Coal of Mine Xishan Coal Electricity Group as the engineering background, the process flow and key technical parameters of the mining technology of self-formed roadway without coal pillars in the middle-thick coal seam were analyzed. The stress distribution of the surrounding rock and the roof displacement of the roadway when the traditional longwall mining method and the top-cutting pre-split blasting heights were 4, 6, and 8 m and the top-cutting angles were 5°, 10°, 15° and 20° were respectively analyzed. The results show that under the conditions of reasonable pre-splitting blasting cutting height and cutting angle, not only can the roof rock layer be forced to collapse in time after the working face is mined and fill the gob, but it can also effectively cut off the stress transmission path between the roadway and the roof rock layer of the gob, so that the stress concentration area is transferred to the depth of the solid coal, and the stress environment of the surrounding rock of the roadway is improved, and it plays the role of roof cutting and pressure relief. Meanwhile, the optimum blasting scheme is obtained through field test. This research has played a theoretical guiding significance for the application of “non-pillar gob side entry retaining formed by roof cutting and pressure release” in medium and thick coal seams.

     

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