In order to reduce the width of the sectional pillar in the coal mining section of the mining block and to improve the coal mining recovery rate of the mining block, a site observation method was applied to analyze two mining operations of the up and low coal mining faces when the sectional coal pillar with a width of 20 m. Under the dynamic pressure role, the max roof displacement of the gateway was 56 mm and the convergence between the two sidewalls of the gateway was 45 mm. In order to further reduce the coal pillar width of the gateway, under the conduction of the previous support mode unchanged, a rational coal pillar width was optimized and determined. The numerical calculation method was applied to simulate the deformation features of the gateway with different width coal pillars. The calculation showed that the gateway with a coal pillar width of 12 m could be kept in stable. The project practices showed that the subsidence of the roof during the driving and mining period was 112 mm in total and the convergence between the two sidewalls was 106 mm in total. The deformation of the gateway could be controlled within the allowed scope and the coal pillar could be in stable to meet the requirements of the mine safety production. There were about 70 000 t additional coal mined recovered from the eoal pillars.%为了减小盘区开采区段煤柱宽度,提高盘区采出率,采用现场观测的方法,分析了原留设20 m宽区段煤柱时,经上下工作面2次回采,动压作用下巷道顶板最大位移56 mm,两帮最大移近量45 mm,为进一步减小护巷煤柱宽,在原有支护方式不变的条件下,优化确定合理煤柱宽度,采用数值计算方法,模拟不同宽度煤柱巷道变形特征,计算显示留12 m宽度煤柱巷道能够保持稳定。工程实践表明,掘进与回采期间顶板下沉量累计112 mm,两帮移近量累计106 mm,巷道变形控制在许可范围之内,煤柱也始终处于稳定,满足了安全生产要求,多采出煤炭7万t。
展开▼
