急倾斜厚煤层采空区稳定性分析及注浆治理效果评价

以某急倾斜厚煤层采空区为对象.首先,通过数值模拟软件进行空区形成模拟,分析最大主应力与竖向位移特征,结合实测数据评价模拟的符合性.结果表明:空区上覆岩层偏向下山煤柱处、上山煤柱偏向下伏岩层处、上覆岩层与上山煤柱交汇处随着集中应力的减小而初期破坏减弱;空区下伏岩层偏向上山煤柱处、下山煤柱与下伏岩层交汇处、下山煤柱偏向上覆岩层处随着应力的增大而初期破坏增强;地表模拟与实际沉降量高度吻合,可以反映空区围岩实际情况.其次,进行空区煤柱失稳模拟,分析并评价围岩的稳定性.表明空区场地最大剩余沉降量为0.3～0.9 m,能破环建筑地基,空区围岩处于失稳状态.最后,模拟空区注浆充填治理,结合现场监测数据评价治理效果.表明现场与模拟监测点最终竖向位移差值在-2.3～8 mm范围,两者基本一致,注浆治理效果显著.可见注浆充填法能有效治理当地类似急倾斜厚煤层采空区失稳问题.

Stability Analysis and Evaluation of Grouting Treatment Effect on Goaf of Steep Thick Coal Seam

Taking the goaf of a steeply inclined thick coal seam as an object. Firstly, the numerical simulation software was used to simulate goaf formation, analyze the characteristics of the maximum principal stress and vertical displacement of surrounding rock, and evaluate the conformity of the simulation in accordance with the actual measured data. The results show that the overlying strata in goaf is inclined to the downhill coal pillar, the uphill coal pillar tilts to the underlying coal stratum, and the overlying strata intersects with the area of uphill coal pillar. At this point, the initial damage of the surrounding rock is weakened with the decrease of concentrated stress. In addition, the underlying stratum in goaf is slanted towards the uphill coal pillar, the downhill coal pillar intersects with the underlying stratum, and the downhill coal pillar tilts to the area of overlying strata. At this point, the initial damage of surrounding rocks is gradually strengthened with the increase of concentrated stress. The simulated surface settlement is highly consistent with the actual surface settlement. This indicates that the numerical simulation can reflect the actual situation of surrounding rock in the goaf. Secondly, the simulation of coal pillar instability in goaf was carried out to analyze and evaluate the stability of surrounding rock in the goaf through numerical simulation software. The results show that the maximum residual settlement of the goaf site is 0.3~0.9 m. It can break the building foundation. Therefore, the surrounding rock of the goaf is in a state of instability. Finally, the numerical simulation software was conducted to simulate the treatment of grouting filling in goaf and evaluate the governance effect with field monitoring data. The results show that the difference value of the final vertical displacement between the field monitoring site and the simulated monitoring site is within the range of -2.3~8 mm, and the two vertical displacement values are roughly identical, thus, the grouting treatment presents a remarkable effect. It is concluded that the grouting filling method can effectively control the instability in the goaf of similar steeply inclined thick coal seam in the same area.