Based on the transmitting theory of "smoke ring effect", the transient electromagnetism technique was used in coal mines to detect abnormal areas of aquiferous structures in both roofs and floors of coal sea...Based on the transmitting theory of "smoke ring effect", the transient electromagnetism technique was used in coal mines to detect abnormal areas of aquiferous structures in both roofs and floors of coal seams and in front of excavated roadways. Survey devices, working methods and techniques as well as data processing and interpretation are discussed systematically. In addition, the direction of mini-wireframe emission electromagnetic wave of the full space transient electromagnetism technique was verified by an underground borehole for water detection and drainage. The result indicates that this technique can detect both horizontal and vertical development rules of abnormal water bodies to a certain depth below the floor of coal seams and can also detect the abnormal, low resistance water bodies within a certain distance of roofs. Furthermore, it can detect such abnormal bodies in ahead of the excavated roadway front. Limited by the underground environment, the full space transient electromagnetism technique can detect to a depth of only 120 m or so.展开更多
The principles,methods,technologies and application effects of several electromagneticmethods for the detection of the hidden danger of water gushing at the coalface were introduced.Also,emphasis was laid on expoundin...The principles,methods,technologies and application effects of several electromagneticmethods for the detection of the hidden danger of water gushing at the coalface were introduced.Also,emphasis was laid on expounding the methods,principles andeffects of down-hole detections by electric transmission tomography and transient electromagneticmethod.The potential of point power supplied in the underground homogeneoussemi-space,as well as the response to a low-resistivity abnormal body in file hemogeneoussemi-space,was simulated by adopting 3-D finite element method to interpretthe basic theory of the electric transmission tomography.The results of actual measurementshow that the mine electromagnetic method is sensitive to water-bearinglow-resistivity bodies and can play a unique role in detecting the hidden danger of watergushing at the coal face.展开更多
文摘Based on the transmitting theory of "smoke ring effect", the transient electromagnetism technique was used in coal mines to detect abnormal areas of aquiferous structures in both roofs and floors of coal seams and in front of excavated roadways. Survey devices, working methods and techniques as well as data processing and interpretation are discussed systematically. In addition, the direction of mini-wireframe emission electromagnetic wave of the full space transient electromagnetism technique was verified by an underground borehole for water detection and drainage. The result indicates that this technique can detect both horizontal and vertical development rules of abnormal water bodies to a certain depth below the floor of coal seams and can also detect the abnormal, low resistance water bodies within a certain distance of roofs. Furthermore, it can detect such abnormal bodies in ahead of the excavated roadway front. Limited by the underground environment, the full space transient electromagnetism technique can detect to a depth of only 120 m or so.
基金Supported by the National Basic Research of China(2006CB202207)the National Natural Science Foundation of China(40674060)
文摘The principles,methods,technologies and application effects of several electromagneticmethods for the detection of the hidden danger of water gushing at the coalface were introduced.Also,emphasis was laid on expounding the methods,principles andeffects of down-hole detections by electric transmission tomography and transient electromagneticmethod.The potential of point power supplied in the underground homogeneoussemi-space,as well as the response to a low-resistivity abnormal body in file hemogeneoussemi-space,was simulated by adopting 3-D finite element method to interpretthe basic theory of the electric transmission tomography.The results of actual measurementshow that the mine electromagnetic method is sensitive to water-bearinglow-resistivity bodies and can play a unique role in detecting the hidden danger of watergushing at the coal face.
