渭北煤田地下水特征及保水采煤研究进展

Hydrogeological characteristics and progress of water-preserving coal mining in Weibei Coalfield

绿色开采已经成为矿山建设的最基本要求。保水采煤作为绿色开采技术体系的重要组成部分,重点在于解决矿区煤层开采过程中地下水资源和生态环境保护问题。通过总结渭北煤田岩溶地下水的水文地质特征,阐明煤层开采与奥灰岩溶水的关系,综述渭北煤田开展保水采煤研究中取得的成果。结果表明:渭北煤田奥灰岩溶水位整体上呈下降趋势,近30年内水位下降了18.5 m左右,下降速率为0.64 m/a。澄合矿区东部及韩城矿区5号煤层均处于岩溶水位水平之下,煤层开采受到岩溶水的严重威胁。5号煤层底板突水机理包括:①底板有效隔水层较厚,断层切割K_2(上石炭统太原组石英砂岩和灰岩含水岩组)与峰峰组二段灰岩含水层之间的铝质泥岩隔水层,水压破坏与采动底板破坏区相互导通,产生突水;②有效隔水层相对较薄,高承压水头产生的破坏区与采动底板破坏区相连,发生突水。将K_2及以下隔水层全面进行注浆改造,使其产生25~30 m的有效隔水层,能实现保水采煤。围绕着注浆改造保水采煤,渭北煤田在地质条件综合探测、注浆材料研发、带压开采预测、地下水监测等方面都取得长足进展。渭北煤田承压水体上保水采煤技术在类似地区具有借鉴意义。

Green mining has become the most basic requirement for mine construction.As an important part of the green mining technology system,water-preserving coal mining focuses on solving the problems of groundwater resources and ecological environment protection in mining areas.By summarizing the hydrogeological characteristics of karst groundwater in Weibei Coalfield,and clarifying the relationship between coal mining and limestone karst water,the achievements made in the research of water-preserving coal mining in Weibei Coalfield were generally reviewed.The results show that the karst groundwater level in Weibei Coalfield has a downward trend as a whole.The groundwater table has dropped by about 18.5 m at a rate of 0.64 m/a in the past 30 years.The eastern part of Chenghe Mining Area and the No.5 coal seam of Hancheng mining area are both below the karst water level,and coal mining is seriously threatened by karst water.The water inrush mechanism of the No.5 coal seam have two types:①The effective water barrier of the floor is thicker,and the fault cuts the aluminum between K2(Quartz sandstone and limestone water-bearing rock group of the Upper Carboniferous Taiyuan Formation)and the second member of Fengfeng Formation limestone aquifer.In the mudstone water-resistant layer,the water pressure failure and the mining floor failure area are connected to each other,resulting in water inrush;②The containment layer is relatively thin,and the damage area caused by the high-pressure water head is connected to the mining floor failure area,which leads to water inrush.The K2 and below water-resistant layer shall be fully grouted to produce an effective aquifer of 25~30 m,which can realize water-preserved coal mining in the area.The water-preserving coal mining technology on the confined water in Weibei Coalfield has certain reference significance in similar areas.