针对大断面沿空掘巷窄煤柱宽度确定的难题,通过FLAC^3D数值模拟研究回采对不同宽度窄煤柱的变形破坏与受力分布规律,确定了窄煤柱合理宽度并成功应用于工程实践。研究结果表明:①随煤柱宽度增加,中间弹性核也在增加;②随工作面向前推进,垂直应力分布由梯形分布逐渐向三角形分布演化,超前20m是转折点,应对回风巷道加强支护;③煤柱宽度对应力分布影响较大,随煤柱宽度的减小,垂直应力分布由梯形分布逐渐向三角形分布演化;④煤柱表面向巷道内的位移随煤柱宽度的增加而缓慢增大,超前工作面5m且煤柱达到6m时,基本趋于稳定;⑤选择5m窄煤柱,并注浆加固,可以满足工程需要。
Aiming at the narrow coal pillar width determination of large section gob - side entry driving in fully mechanized top caving face, FLAC3D numerical simulation was applied to study the laws of mining - induced deformation and stress distribution for coal pillars of different widths, the reasonable width was determined and applied to engineering practice. The results show that: ①With the increase of the coal pillar width, the width of elastic kernel increases ; ②With the working face advance, the vertical stress distribution changes gradually from trapezoidal distribution into triangular distribution, the turning point is at 20m, to air -return roadway support should be strengthened; ③The coal pillar width has great influence on distribution of stress influence, with decreasing the width of coal pillar, the vertical stress distribution changes gradually from trapezoidal distribution into triangular distribution; ④The displacement of the coal pillar to the roadway increases gradually with pillar width, and which is 5m ahead of working face and trends to be stable when coal pillar width reaches 6m ; ⑤The enzineering need can be satisfied using 5m coal pillar with grouting reinforcement.