半固结砂岩含水层下多煤层重复采动突水溃砂危险性分析

Risk Analysis of Water and Sand Burst in Multiple Coal Seams Repeated Mining under Semi-consolidated Sandstone Aquifer

针对半固结砂岩含水层下的多煤层安全开采问题,分析了多重含水层分布特点、半固结砂岩力学参数,研究了多重煤层重复采动覆岩破坏高度,给出了相应安全煤岩柱的留设尺寸,分析了多煤层采动影响受多重含水层的充水溃砂影响。从导水通道、含水层水压力、工作面排水能力3个方面出发,提出“采前疏降、顶疏结合、疏采相辅”的控水采煤技术。研究发现半固结砂岩弱化了导水裂缝带发育程度,重复采动过程中导水裂缝逐渐波及Ⅱ2a煤层采空区,即Ⅱ3煤层顶板含水层水、Ⅱ2a煤层采空区积水对工作面开采具有充水溃砂影响,一含与二含对工作面开采具有充水影响。

Aiming at the problem of safe mining of multiple coal seams under semi-consolidated sandstone aquifers,the distribution characteristics of multiple aquifers and the mechanical parameters of semi-consolidated sandstone were analyzed,and the damage height of overlying strata under repeated mining of multiple coal seams was studied.The set size of corresponding safe coal rock pillars were given.The impact of multiple coal seams mining affected by the impact of water filling and sand collapse of multiple aquifers was analyzed.Starting from the three aspects of water channel,water pressure of aquifer and drainage capacity of working face,the water-control coal mining technology of"pre-mining dredging,roof dredging combined,dredging supplemented"was proposed.The study found that the semi-consolidated sandstone weakened the development of the water-conducting fracture zone During repeated mining,the water-conducting fractures gradually spread to theⅡ2acoal seam goaf that is,theⅡ3coal seam roof aquifer water and theⅡ2acoal seam goaf water accumulated on the working face.It had the influence of water filling and sand breaking,and the first and second containment had the influence of water filling on the mining of the working face.