特厚煤层沿空掘巷合理留设小煤柱的试验研究

Experimental study on reasonable leaving of small coal pillar for gob-side entry driving in extra-thick coal seam

为减少煤柱损失量,改善巷道维护现状和提高煤炭回采率,以庞庞塔煤矿10#特厚煤层为工程背景,采用理论计算、FLAC3D数值模拟和现场观测方法对该矿特厚煤层综放沿空掘巷留设的小煤柱宽度进行了研究。计算表明:小煤柱合理留设宽度为7.7~9 m。以小煤柱理论计算为基础,结合工作面端头侧的应力与煤柱侧向支承压力分布特征,提出了4种小煤柱留宽方案,通过数值模拟对比分析不同留宽煤柱在掘巷和回采阶段的围岩应力和受载变形情况,最终得出小煤柱合理留宽为9 m。工程实践表明:按9 m留设区段煤柱,并采用合理支护设计,巷道顶底板及两帮变形量较小,煤柱稳定性良好,留宽方案满足生产使用要求。

In order to reduce the loss amount of coal pillar,improve the status of roadway maintenance and raise the coal recovery rate,the width of small coal pillar leaving in the fully-mechanized gob-side entry driving in the extra-thick coal seam was studied by using the methods of theoretical calculation,numerical simulation of FLAC^(3D) and field observation through taking 10~# extra-thick coal seam in Pangpangta Mine as the engineering background.The results showed that the reasonable leaving width of small coal pillar was 7.7-9 m.Based on the theoretical calculation of small coal pillar,four schemes about the leaving width of small coal pillar were put forward combining with the distribution characteristics of the stress at the end of the working face and the side abutment pressure of the pillar.The surrounding rock stress and loading deformation of coal pillar with different leaving widths in the stages of roadway excavation and mining were compared and analyzed through the numerical simulation,and finally the reasonable leaving width of small coal pillar was determined to be 9 m.The engineering practice showed that when leaving the sectional coal pillar with 9 m and adopting the reasonable support design,the deformation of the roof,floor and sides of the roadway were small,and the stability of coal pillar was good,so the scheme of leaving width could satisfy the production using requirements.