陕西煤炭

在特厚煤层巷道掘进过程中，如何在临空巷道掘进过程中保证巷道围岩稳定，降低掘进扰动产生的冲击风险是一个亟待解决的关键问题。采用理论分析、数值模拟、现场实测等方法，研究分析了临空巷道掘进过程中上覆岩层应力变化规律，提出了临空巷道掘进煤柱上覆岩层“应力重构”假设，分析了在3种应力状态下发生冲击的可能性；通过数值模拟，判断在不同煤柱尺寸下的巷道塑性区范围变化趋势。结果表明，特厚煤层临空巷道掘进过程中，二次掘进巷道应力值的升高是导致发生冲击的主要因素。通过数值模拟，当煤柱宽度大于等于30 m时，两侧的塑性区范围达到稳定，巷道两帮弹性能降到最低。采用应力监测和巷道三量监测进行效果检验，在煤柱宽度优化、“大直径+爆破卸压”“锚索+双网+大托盘”联合支护的基础上，最大应力值达到9 MPa,巷道围岩变形量均控制在巷道断面的10%以内，巷道掘进期间冲击地压防治效果显著，为后期冲击地压煤层临空掘进积累了经验。

In the process of excavating thick coal seam roadways, how to ensure the stability of the surrounding rock during the excavation of gob-side roadways and reduce the impact risk caused by excavation disturbance is a key problem that needs to be solved urgently.The paper uses analytical methods, numerical simulation, and field measurements to study the law of stress changes in the overlying rock layer of gob-side roadways during excavation.It proposes the “stress reconstruction” hypothesis for the overlying rock layer of the coal pillar in go-side roadways, analyzes the possibility of impact occurring under three stress states; and uses numerical simulation to determine the trend of the plastic zone range change in different coal pillar dimensions.The results show that: The secondary excavation of the gob-side roadway during the excavation of thick coal seam results in an increase of stress values, which is the main factor leading to the occurrence of impact.Through numerical simulation, when the width of the coal pillar is equal to or greater than 30 m, the plastic zone ranges on both sides reach stability, and the shear strength of the roadway sides is reduced to the lowest.The effects are verified by stress monitoring and monitoring of the three parameters of the roadway, and the maximum stress value reaches 9 MPa and the deformation of the surrounding rock in the roadway is controlled within 10% of the cross-sectional area of the roadway after optimizing the width of the coal pillar, using “large diameter+blasting pressure relief”,and “bolt anchors+double nets+large support plate” combined support.