超长工作面开采下区段煤柱留设合理宽度分析

Reasonable width of coal pillar retaining in the lower section of ultra-long working face mining

为确定超长工作面开采下区段煤柱合理留设宽度,分析超长工作面侧向支承压力在煤柱中的分布特征,利用数值模拟软件研究区段煤柱中的应力分布,并在现场区段煤柱不同深度中布置钻孔应力计,监测侧向支承压力的变化规律。结合巷道围岩稳定性综合监测分析,研究超长工作面采动影响下巷道围岩的变形破坏特征,进而优化支护参数,以保障超长工作面回采巷道的通畅与安全。研究结果表明,在11205工作面右端、11207工作面左端及其煤柱区域位置煤柱内部应力分布呈现出明显的3处应力集中,其煤柱位置的应力集中效应更为明显;增大煤柱宽度能够有效改善煤柱应力分布状态,但当煤柱宽度超过16 m后,应力变化不大。工作面开采后,11207工作面采空区顶板位移量明显增大,整体位移变为以煤柱为中心的扇形沉陷,说明煤柱对上覆岩层起到了支撑作用。根据数值计算结果,得出煤柱留设宽度在16 m煤柱较为合适;由煤柱顶底板破坏强度可知,留设16~20 m的煤柱较为合适。

The distribution characteristics of the lateral abutment pressure in the coal pillar of the ultra-long working face are studied,and the stress distribution in the coal pillar of the section is studied using the numerical simulation.The change law of the lateral abutment pressure is monitored by placing the borehole stress meter in the different depths of the coal pillar in the field section,and the scientific determination of width of the coal pillar is guided.To carry out the comprehensive monitoring and analysis of the stability of roadway surrounding rock,we study the deformation and failure characteristics of roadway surrounding rock under the influence of mining on ultra-long working face,optimize supporting parameters,and ensure the smooth and safety of mining roadway on ultra-long working face.The results show that:the internal stress distribution of coal pillar presents three obvious concentrated stress distribution states at the right end of 11205 face,the left end of 11207 face and the coal pillar area,and the stress concentration effect is more obvious at the coal pillar location.Increasing the width of coal pillar can effectively improve the stress distribution state of coal pillar,but when the width of coal pillar exceeds 16 m,a little change occurs.After the mining of the working face,the roof displacement of the goaf in the working face 11207 increases significantly,and the overall displacement becomes a fan-shaped subsidence centered on the coal pillar,indicating that the coal pillar supports the overlying strata.According to the numerical calculation results,it is more appropriate to know that the width of the coal pillar is 16m.From the failure strength of the roof and floor of the coal pillar,it can be seen that the coal pillar of 16~20 m should be retained.