用瞬变电磁法探查综放工作面顶板水体的研究

随着机械化综采设备在煤炭开采中的普及,对煤层顶板管理要求愈来愈高,其中煤层顶板水害体的发育将影响综采设备充分发挥效能,甚至会威胁工作面安全回采．提前查明煤层顶板水害体发育位置,为在井下布置探放水钻孔提供依据,是目前矿井地球物理勘探亟待解决的问题．基于地面瞬变电磁法理论及应用技术,根据井下实际应用环境,研究出采用非接触式、多匝数的正方形重叠回线（边长2m左右）装置探测工作面顶板水害体发育位置．依据瞬变电磁场”烟圈效应”理论和物理模拟相似准则,推导出全空间瞬变电磁法视电阻率计算数学模型,并对矿井瞬变电磁探测综放工作面顶板水害技术进行了研究．采用矿井瞬变电磁技术查明综放工作面顶板水害体发育位置,通过井下疏放水钻孔和工作面回采资料验证,该方法探测综放工作面顶板水害体发育的空间位置不仅行之有效,而且明显优越于其它矿井物探方法．

Transient Electromagnetic Detecting Technique for Water Hazard to the Roof of Fully Mechanized Sub-Level Caving Face

In coal mining,with the popularization of fully mechanized equipment,the roof control becomes more and more important.The development of water body in roofs may seriously affect the efficiency of the fully mechanized mining,quite possible to cause an accident in working face.Therefore,to make clear the position of a water body located in roofs so as to provide a basis for water drainage borehole layout is an urgent problem to be solved by geophysical exploration.Based on the transient electromagnetic theory and the technique used on ground surface and on the actual situation in underground coal mines,a square superimposed loop device(2 m in side length) which is non-contact and multi-turns was developed to detect the water bodies in coal seam roofs.Based on the "smoke ring effect" theory and the physical simulation criterion,the mathematics model for calculating the apparent resistivity of full space transient electromagnetism is deduced.In addition,the water detection technology for the roof of fully mechanized sub-level caving face was researched and applied in several coal mines,which has been verified by boreholes and mining practice,indicating that this method is very effective in detecting the water source in the roof of fully mechanized sub-level caving face.