Shanxi Ningwu Yushupo Coal Industry Corporation Ltd.

临空巷道围岩变形控制是巷道控制的技术难点,煤层开采厚度越大、覆岩强度越高,临空巷道变形控制难度越大。针对榆树坡煤矿大采高工作面开采的临空巷道动压控制难题,建立了临空巷道侧向悬板结构的力学模型,理论分析得到基本顶侧向最大悬顶长度为4.69m,基本顶应变能密度最大值位于煤柱内5.51m处,其值为2.831×106J/m3,基本顶积聚应变能为3.269×107J。进一步采用数值模拟的手段对临空巷道围岩塑性区发育、变形规律及围岩应力分布特征进行分析,得到临空煤柱支承应力可达35MPa以上,是造成巷道煤柱帮锚杆索受力程度大、煤柱帮变形破坏的主要因素。现场采用“卸压孔+侧向切顶”的综合技术手段对临空动压巷道进行控制,设计卸压孔孔径为108mm,孔深7m;水力压裂孔分为L孔、S孔,孔径60mm,间距8m,垂直压裂高度分别为50m、30m,注水量80L/min。现场实践表明,相比未实施卸压措施段,巷道围岩变形量减少30%以上,巷道底鼓情况得到明显控制。

Wall rock deformation control of gob - side roadway is a technical difficulty of roadway control. The greater the mining thickness of coal seam and strength of overlying rock are, the more difficult the gob-side entry deformation control is. Aiming at solving the problem of dynamic pressure control of gob-side roadway for large mining height working face at Yushupo Coal Mine, the mechanical model of lateral hanging plate structure for gob-side roadways was established. The theoretical analysis shows that the maximum lateral hanging length of main roof is 4. 69 m, and the maximum strain energy density of main roof is located at 5. 51 m in coal pillars, which is 2. 831×10 J/ m , and the accumulated strain energy of main roof is 3. 269× J. By means of numerical simulation, the development of plastic zone, deformation law and stress distribution characteristics of surrounding rocks in gob-side roadway were further analyzed. It was found that the supporting stress of goaf coal pillars can reach more than MPa, which is the main factor for increasing stress on bolt and cable in roadway coal pillars and the deformation and failure of coal pillars. The comprehensive in-site technical methods of “pressure relief hole+lateral roof cutting” were used to control the dynamic pressure gob-side roadways. The design diameter of the pressure relief hole is mm and the depth is m. The hydraulic fracturing holes are L hole and S hole, the aperture is 60mm, the spacing is m, the vertical fracturing height is m and m, respectively, and the water injection rate is L/ min. According to the in-site practice, the deformation of wall rocks of roadways was reduced by more than 30% compared to the section without pressure relief, and the floor heave of roadways was obviously controlled.

高朝,张超.大采高工作面临空巷道动压显现机理及预控技术研究[J].煤炭工程,2024,56(9):112-120.