采区下山煤柱下伏巷道底鼓力学机理

Mechanical Mechanism of Floor Heave in Underlying Roadway under Coal Pillars in Mining Area

针对采区下山煤柱下伏巷道底鼓的问题,采用理论分析、数值模拟方法,对煤柱下巷道底板变形规律进行分析,并提出防治方法。研究结果表明:煤柱区集中应力影响下,下部岩层主要以垂直应力分布为主;基于弹性地基梁理论,得到了巷道底板挠曲线微分方程,分析发现,采区下山煤柱下伏巷道底鼓主要由上覆载荷过载所致,同时数值模拟也发现,随着采区两翼开采完毕后,采区下山煤柱上覆岩层形成“T”形空间结构,覆岩载荷通过“T”形空间结构由煤柱传递至下伏巷道围岩,围岩应力增幅达到50%;针对采区下山保护煤柱下巷道底鼓力源,提出了底板爆破预裂防治底鼓的方案,效果显著.

In response to the problem of floor heave in the roadway beneath the coal pillar in the mining area,theoretical analysis and numerical simulation methods are used to analyze the deformation law of the roadway floor under the coal pillar,and prevention and control methods are proposed.The research results indicate that under the influence of concentrated stress in the coal pillar area,the lower rock layer is mainly dominated by vertical stress distribution;based on the theory of elastic foundation beam,the differential equation of the deflection curve of the tunnel floor was obtained.Analysis showed that the bottom bulge of the tunnel under the coal pillar in the mining area was mainly caused by the overload of the overlying load.At the same time,numerical simulation also found that as the two wings of the mining area were mined,the overlying rock layer on the coal pillar in the mining area formed a"T"-shaped spatial structure,and the overlying rock load was transmitted from the coal pillar to the surrounding rock of the underground tunnel through the"T"-shaped spatial structure,with a stress increase of 50%in the surrounding rock;a plan for preventing and controlling bottom heave by bottom blasting pre cracking has been proposed for the protection of the force source under coal pillars in the mining area.The effect is significant.