厚煤层综放工作面区段煤柱合理宽度优化研究

Optimization Research on Reasonable Width of Section Coal Pillar in Fully Mechanized Caving Face of Thick Coal Seam

厚煤层放顶煤开采实践中,区段煤柱留设宽度与巷道围岩的稳定性相关性极大,区段煤柱留设较小时巷道围岩稳定性较差,受回采影响易发生巷帮外挤、顶板冒落等事故,而煤柱宽度留设过大则造成资源极大浪费。以高河煤矿西一盘区为工程背景,理论分析了巷道围岩变形大的原因,采用数值模拟的方法研究了采空区侧向的应力分布特征、位移变形规律、破坏特征。现场监测数据表明,工作面超前90 m范围外围岩变形缓慢,巷道顶底板及两帮最大变形量均小于50 mm,超前工作面90 m的影响范围内,巷道受到超前集中应力影响而变形剧烈;巷道顶、底板移近量最大为848 mm,两帮移近量最大为583 mm,区段煤柱优化后,巷道变形较优化前有了显著的降低,巷道顶、底板移近量降低了43.76%,两帮移近量降低了35.93%,综合考虑资源回收、巷道稳定性、次生灾害控制等因素,确定厚煤层综放工作面区段煤柱宽度为32 m。

In the practice of top coal caving mining in thick coal seam,the reserved width of section coal pillar has a great correlation with the stability of roadway surrounding rock.When the width of section coal pillar is small,the stability of roadway surrounding rock is poor,and under the influence of mining,it is easy to have accidents such as roadway wall extrusion and roof caving.When the width of coal pillar is too large,it will cause great waste of resources.Taking the production geological conditions in the west panel of Gaohe Coal Mine as engineering background,the causes of large deformation of roadway surrounding rock were analyzed theoretically.The numerical simulation method was used to study the lateral stress distribution characteristics,displacement deformation law and failure characteristics of goaf.The field application verification shows that the deformation of surrounding rock is slow outside the range of 90 m ahead of the working face,and the maximum deformation of the roof,floor and two sides of the roadway is less than 50 mm.Within the range of 90 m ahead of the working face,the roadway is severely affected by the advanced concentrated stress.The maximum displacement of roof and floor is 848 mm,and the maximum displacement of two sides is 583 mm.Compared with the original scheme,the displacement of roof and floor is reduced by 43.76%,and the displacement of two sides is reduced by 35.93%after optimization.The deformation of roadway is significantly reduced compared with that before optimization.In consideration of resource recovery,roadway stability,secondary disaster control and other factors,the width of section coal pillar in fully mechanized caving face of thick coal seam is determined to be 32 m.