基于底鼓控制的软岩回采巷道合理护巷煤柱宽度研究

Research on Reasonable Coal Pillar Width of Roadway Protection in Soft Rock Based on Floor Heave Control

针对敏东一矿I0116306工作面回风顺槽在留设30 m保护煤柱宽度下,巷道底鼓剧烈的问题,采用现场监测、理论分析、数值模拟等研究方法,建立了朗肯土压力理论巷道底鼓力学模型,研究了巷道底板破坏深度的影响因素及不同煤柱宽度影响下煤柱的垂直应力分布和巷道底板塑性区分布形态。结果表明:煤柱内垂直应力集中系数是导致巷道底鼓的主要因素。当煤柱宽度较小时,煤柱发生失稳破坏,巷道底板发生大面积塑性破坏,最大破坏深度出现在靠近煤柱侧;煤柱宽度过大时,煤柱内垂直应力集中系数降低,煤柱内塑性区基本不再变化,巷道底板塑性区靠近煤柱侧有增大趋势。综合考虑资源回采率及巷道底板变形破坏规律,最终确定敏东一矿软岩巷道保护煤柱合理宽度为20 m。

Aiming at the problem of severe swelling of the roadway in the return airway of Mindong No.1 mine I0116306 working face with a protection pillar width of 30 m, on-site monitoring, theoretical analysis, numerical simulation, and other research methods were used to establish the Rankine earth pressure theory. The mechanical model of the roadway floor heave has studied the influencing factors of the roadway floor failure depth and the vertical stress distribution of the coal pillar under the influence of different coal pillar widths and the distribution pattern of the roadway floor plastic zone. The results show that the vertical stress concentration factor in the coal pillar is the main factor leading to the floor heave of the roadway. When the width of the coal pillar is small, the coal pillar will be destabilized and damaged, and the roadway floor will undergo large-scale plastic failure. The maximum depth of failure occurs near the side of the coal pillar;when the width of the coal pillar is too large, the vertical stress concentration factor in the coal pillar will decrease and the coal pillar, the inner plastic zone basically no longer changes, and the plastic zone of the roadway floor near the coal pillar side tends to increase.Considering the resource recovery rate and the deformation and failure law of the roadway floor, it is finally determined that the reasonable width of the protection coal pillar of the soft rock roadway in Mindong No. 1 mine is 20 m.