非均匀条带开采煤柱稳定性及地表变形规律分析

采用理论分析及数值模拟相结合的方法,分析了非均匀煤柱条带开采中的煤柱稳定性及地表变形规律,并与常规均匀条带开采进行对比。结果表明:条带开采中,煤柱受力存在明显的不均匀性,最中间的煤柱受力最大,两侧煤柱受力较小,塑性区宽度也稍小于最中间煤柱。随着最中间煤柱宽度的增加,所受应力逐步降低,煤柱弹性承载区面积逐步增大,煤柱的稳定性增加。从系统论的观点出发,要提高整个煤柱系统的稳定性,可以提高最容易发生失稳破坏的最中间煤柱的稳定性。同时,地表沉陷值从480mm减少为420,400mm,煤柱的冲击倾向性也降低。因此,非均匀煤柱条带开采有利于提高煤柱承载系统的稳定性,减少地表沉陷及冲击地压的发生。

Stability of Coal Pillar and the Law of Earth Surface Subsidence in the Non-uniform Strip Mining

With the combination of theoretical analysis and numerical simulation method, the stability of coal pillar and the law of earth surface subsidence in the non-uniform strip mining was analyzed and compared with conventional homogeneous strip mining. The stress was formed in obviously non uniform pattern in the strip mining and that acting in the middle pillar was the largest; it was smaller on both sides of the pillars, and the plastic zone width was slightly smaller than the middle pillar. With the coal pillar in the middle increasing, the stress gradually decreased, and elastic bearing area of coal pillar increased gradually and the stability of coal pillar improved. Meanwhile the stir- face subsidence value decreased from 480 mm through 420 mm to 400 mm,and impact tendency of coal pillar was al so reduced. To improve the stability of coal pillar system,the stability of the most fragile middle coal pillar should be increased in light of system theory. The results indicate that non-uniform strip mining can improve the stability of coal pillar bearing system reducing surface subsidence and the occurrence of percussive ground pressure.