特厚煤层综放面区段煤柱合理尺寸研究

Study on reasonable size of section coal pillar in fully mechanized caving face in extra-thick coal seam

根据金庄矿8203特厚煤层综放面实际,采用理论分析、数值模拟以及现场实测相结合的方法确定了区段煤柱合理宽度。理论研究了煤层厚度、应力集中系数、煤层强度对煤柱宽度的影响,确定区段煤柱宽度应大于23 m。采用FLAC3D模拟了煤柱宽度为16 m、20 m和24 m时,其两侧工作面开采过程中煤柱内塑性区和应力分布及变化规律,模拟结果表明煤柱宽度为16 m、20 m时,在两侧工作面回采的过程中,塑性区将会贯通煤柱;当煤柱宽度增加到24 m时,塑性区没有贯穿整个煤柱,煤柱内部存在8 m宽的弹性区。现场实测表明左侧工作面回采过程中煤柱破坏宽度为5 m左右,右侧工作面回采阶段煤柱破坏宽度为15 m,故首采工作面采用30 m宽的煤柱尺寸偏大,同理本研究也为后续工作面选择合理的区段煤柱尺寸提供了指导。

According to actual condition of 8203 fully mechanized caving face in extra-thick coal seam in Jinzhuang Mine,the reasonable size of section coal pillar was determined by theoretical analysis,numerical simulation and field measurement.The effects of seam thickness,stress concentration factor and coal strength on pillar width were analyzed by theoretical study,and it confirmed that the width of section coal pillar must be greater than 23 m.The distribution and change rules of plastic zone and stress in coal pillar in the mining process of working faces on both sides of coal pillar were simulated by FLAC 3D when the width of coal pillar was designed as 16 m,20 m or 24 m.The results showed that when the width of coal pillar was 16 m or 20 m,the plastic zone could get throughout the pillar;when the width was 24 m,the plastic zone could not get through the pillar and there was an 8 m wide elastic zone in the pillar.Field measurement indicated that the failure width of the section coal pillar in the mining process of the left-side face and right-side face were respectively 5 m and 15 m,so the 30 m wide coal pillar in first mining face was too large.This research also provided guidance for follow-up working face mining to select reasonable size of section coal pillar.