新集矿区深部1煤层底板奥灰岩溶突水危险性评价

Water inrush risk assessment of Ordovician limestone karst in the floor of deep coal seam 1 in Xinji mining area

奥灰岩溶裂隙含水层是影响华北型煤矿深部开采的重要水害,在水-岩相互作用下奥灰含水层易导致煤层底板突水。为进一步认识奥灰岩溶突水问题,文章以新集矿区深部1煤层开采为例,利用矿区近些年最新积累的奥灰钻孔资料,选取断层强度指数、断层交叉点与尖灭点、含水层水压、富水性、隔水层等效厚度、脆塑比7个因素作为奥灰岩溶突水的主控因素,并结合层次分析法(analytic hierarchy process,AHP)确定各主控因素影响权重。运用地理信息系统(geographic information system,GIS)空间分析功能建立各主控因素专题图,通过对专题栅格图归一化处理,将各主控因素按照权重进行空间复合叠加,最终获得1煤层底板奥灰岩溶突水危险性评价分区结果。将评价结果与突水系数法计算结果对比分析可知,基于GIS的煤层底板突水危险性评价方法更符合矿区实际地质情况,可以为矿区深部煤层开采与水害防治工作提供参考依据。

The Ordovician limestone karst fissure aquifer is a main water hazard affecting the deep mining of North China type coal mine,and the Ordovician limestone aquifer is easy to cause water inrush in coal seam floor under the water-rock interaction.In order to further explore the Ordovician limestone karst water inrush,this paper took the mining of deep coal seam 1 in Xinji mining area as an example,and used the latest accumulation of borehole data of Ordovician limestone in recent years to select seven factors as the main control factors of Ordovician limestone karst water inrush,namely fault strength index,fault crossing point and peak point,aquifer water pressure,water richness,equivalent thickness of water-proof layer and brittle-plastic ratio.The analytic hierarchy process(AHP) was used to determine the influence weights of each main control factor.Using geographic information system(GIS) spatial analysis function,thematic maps of the main control factors were established.Through the normalization of the thematic grid map,the spatial composite superposition of the main control factors was carried out according to the weight,and finally the zoning results of the risk assessment of Ordovician limestone karst water inrush in the floor of coal seam 1 were obtained.By comparing the evaluation results with the calculation results obtained by water inrush coefficient method,it can be seen that the GIS-based coal seam floor water inrush risk assessment method is more in line with the actual geological situation of the mining area,and can provide reference for deep coal seam mining and water hazard prevention and control.