深部强压工作面水力压裂卸压防控效果研究

Study on pressure relief prevention and control effect of hydraulic fracturing in deep pressurized working face

潞安化工集团余吾煤业S5207回风巷掘进过程中,部分巷道出现底鼓、顶角帮鼓和顶板下沉等问题,同时存在断锚杆锚索和响煤炮等动力显现情况。经测量得知,该工作面存在方向为N21.5°E的最大水平主应力为9.15 MPa,最小水平主应力为4.97 MPa,垂直方向上的主应力为10.9 MPa。为解决这一问题,针对S5207深部强压工作面,采用水力压裂技术工艺来弱化坚硬难垮顶板。经过对压裂段和非压裂段的检测点进行位移、应力和荷载检测,结果显示,在压裂段中,顶底板的移近率和两帮的收缩率相比非压裂段分别降低了43.8%和37.9%。压裂段滞后工作面的应力值稳定在平均13.05 MPa,而非压裂段工作面的应力持续增长,最终平均值达到18.6 MPa。在超前工作面的位置,压裂段工作面出现了超前支承应力峰值,平均值为13.0 MPa,增幅为2.1 MPa,超前支承应力集中系数约为1.2。综上所述,水力压裂技术能够明显减轻相邻工作面回采动压,降低巷道受力和围岩变形,有效弱化坚硬顶板,提高巷道整体安全性,并保证动压巷道留巷成功率。该技术的应用,不仅解决了余吾煤业动压巷道的技术难题,还取得了一定的技术、经济和社会效益,并为类似条件下的巷道卸压提供了宝贵的经验。

During the driving process of S5207 return airway in Yuwu Coal Industry,Lu′an Chemical Group,problems such as floor heave,top corner heave and roof subsidence occurred in some roadways,and there were dynamic manifestations such as broken anchor rods,cables,and sound coal cannons.The measurement showed that the maximum horizontal principal stress in the direction of N21.5°E was 9.15 MPa,the minimum horizontal principal stress was 4.97 MPa,and the vertical principal stresswas 10.9 MPa.In order to solve this problem,hydraulic fracturing technology was adopted for the S5207 deep pressurized working face to weaken the hard and difficult to collapse roof.After the displacement,stress and load detection at the detection points in the fractured and non-fractured sections,the results showed that in the fractured section,the proximity rate of the roof and floor and the shrinkage rate of the two sides were reduced by 43.8%and 37.9%,respectively.The stress value of the lagging working face in the fractured section remained stable at an average of 13.05 MPa,while the stress on the non-fractured section continued to increase,reaching a final average of 18.6 MPa.In the position of the advcance working face,the peak value of the advcance timbering stress appears in the working face of the fractured section,the average value was 13.0 MPa,the increase was 2.1 MPa,and the advcance timbering stress concentration coefficient was about 1.2.To sum up,the hydraulic fracturing technology can significantly reduce the coal winning dynamic pressure of adjacent working faces,reduce roadway stress and surrounding rock deformation,effectively weaken the hard roof,improve the overall safety of roadway,and ensure the success rate of roadway retention under dynamic pressure.The application of this technology not only solves the technical problems of the dynamic pressure roadway in Yuwu Coal Industry,but also obtains certain technical,economic and social benefits,and provides valuable experience for the pressure relief of the roadway under similar conditions.