基于瞬变电磁法的近直立特厚煤层卸压效果评价研究

Evaluation of pressure relief effect of near vertical extra thick coal seam based on transient electromagnetic method

现有的卸压效果评价研究多针对于倾斜或缓倾斜煤层,对近直立特厚煤层的适用性尚不明确,近直立特厚煤层进行卸压爆破后其卸压效果难以判断。以乌东煤矿南采区B3+6煤层为工程背景,结合现场监测和理论分析,利用瞬变电磁法研究近直立特厚煤层卸压效果,发现实施深浅孔卸压爆破和煤层注水等措施后的卸压区与未卸压区域相比,顶板视电阻率降低50%~58.33%、煤层降低28.57%~42.86%、底板降低70%~80%。表明煤岩体裂隙发育程度增大、围岩承载载荷的能力降低,不易发生应力集中现象,卸压效果良好。

Existing researches on the evaluation of pressure relief effects are mostly aimed at inclined or gently inclined coal seams,the applicability to near-vertical extra-thick coal seams is not yet known.It is difficult to judge the pressure-relief effect of near-vertical extra-thick coal seams after pressure-relief blasting.Taking the B3+6 coal seam in the southern mining area of Wudong Coal Mine as the engineering background,combining with on-site monitoring and theoretical analysis,the decompression effect of the near-upright extra-thick coal seam is studied using the mine transient electromagnetic.It is found that the after the implementation of deep and shallow hole pressure relief blasting and coal seam water injection,the apparent resistivity of the roof is reduced by 50%~58.33%,the coal seam is reduced by 28.57%~42.86%,and the floor is reduced by 70%~80%.It shows that the degree of fracture development in coal and rock masses increases,the load-bearing capacity of surrounding rocks decreases,stress concentration is not easy to occur,and the pressure relief effect is favorable.