南梁煤矿近距煤层采空区下开采工作面矿压规律研究

Strata behaviors of working face under goaf of close seam in Nanliang coal mine

上煤层覆岩结构失稳特征是影响下煤层开采工作面矿压显现的主要因素。针对南梁煤矿30103工作面浅埋近距离煤层采空区下开采条件,采用相似模拟实验及理论分析对覆岩垮落特征和支架阻力进行了模拟研究。结果表明:采空区下开采,基本顶初次来压步距45 m,周期来压步距6~16 m,支架工作阻均小于8500 kN;走向煤柱下开采,基本顶初次来压步距50 m,周期来压步距10~14 m,支架工作阻均小于9000 kN。工作面在集中煤柱下25 m和出煤柱7 m处,上覆岩层发生滑落失稳,对工作面形成明显的动载冲击,支架阻力超过额定阻力,最大值达13158 kN。集中煤柱弱化后,释放了煤柱集中应力,使得来压时上覆岩层形成相互协调破坏,避免了基本顶滑落失稳形成的载荷瞬态释放,支架阻力仅达到8743 kN。采空区下开采顶板动压防控的优先次序为集中煤柱>走向煤柱>采空区。

The instability characteristics of overburden structure in the upper coal seam are the main factors affecting the behavior of coal pressure in the lower coal seam mining face.In this paper,according to the mining conditions of the goaf in No.30103 face of Nanliang coal mine,the similar simulation experiment was conducted to explore the overburden caving characteristics and support resistance with thoretical analysis results in view.The result shows that the initial caving distance of the main roof is 45 m,the periodical caving distance is 6~16 m,and the resistance of the support is less than 8500 kN under the gob area.When mining under the strike coal pillar,the initial caving distance of the main roof is 50 m,the periodic caving distance is 10~14 m,and the resistance of the support is less than 9000 kN.When the working face is 25 m below the concentrated coal pillar and 7 m out of the coal pillar boundary,the overlying strata will be sliding and destabilizing,forming obvious dynamic impact on the working face.The support resistance exceeds the rated resistance,and the maximum value is up to 13158 kN.With the concentrated coal pillar weakened,the stress of the coal pillar is released,which makes the overlying strata form a coordinated failure,and avoids the transient release of the load caused by the basic roof sliding instability.The support resistance is only 8743 kN.The priority of roof dynamic pressure prevention and control under goaf is concentrated coal pillar>strike coal pillar>goaf.