| The radio wave perspective method is used for the exploration of mine geological structure,which is of great significance to ensure the safe and efficient mining of the working face.This paper adopts the method of combining theoretical analysis,numerical simulation,physical simulation and field engineering application cases to study the three-component perspective method of radio waves in the coal mining face,and obtains the following understanding:(1)Using electromagnetic wave simulation software,a numerical model of radio wave detection was established.As the receiving coil is farther away from the transmitting coil,the field strength values of the three components show an attenuation trend.The electromagnetic wave attenuation curve of X component is more smooth,but there are some fluctuations in the electromagnetic wave attenuation curve of Y component and Z component;In the underground full space model,at the same frequency,when the X-component electromagnetic wave propagates in the coal seam and the coal seam containing faults,when the electromagnetic wave passes through the fault,the resistivity is lower than that of the coal seam,and the electromagnetic wave is absorbed and attenuated faster.The measured field strength in the area with fault structure is significantly lower than that in the normal level coal seam.Through setting the fault influence range,it is found that the wider the fault influence range is,The greater the propagation interference of the fault to the electromagnetic wave,the Y component and Z component change the receiving direction.The electromagnetic wave propagates along the 45 °and 90 °direction angles of the transmitting coil respectively and attenuates with the propagation distance.When encountering the fault,the electromagnetic wave propagation is more complex,and the detection effect is not obvious.(2)The ground test shows that the curve of X component will approach a stable value when the transmitter and receiver enter the target body at the same time,which is helpful to determine the location of abnormal body.For the Z component,after both the transmitting and receiving ends enter the abnormal body,the field strength curve has not reached a stable value,and there is a downward trend,which has a certain interference effect on judging the position of the abnormal body.For the Y component,the curve of the measured field strength will have some fluctuations.It may be that the measurement of the Y component is seriously affected by external interference.When there is a small interference,the observed value will be greatly affected.(3)Underground tests show that in the three-component perspective of radio waves used for Xieqiao Mine,the signal data received on the X component responds best to the fault.The Y and Z components have a certain reaction effect and can be used as auxiliary detection.According to the three-component detection data,the field strength distribution and electromagnetic wave absorption coefficient in the working face were obtained,and the fault influence zone was delimited,which was consistent with the recovery verification results.The three-component detection results of radio waves on the working face effectively guide the safe recovery of the working face.Figure [41] table [10] reference [96]... |
PDF Full Text Request