Wireless electromagnetic wave perspective law of geological anomaly in working face
In order to study the impact of coal(rock)layers and geological anomalies on the perspective of electromagnetic waves,a 3D numerical simulation method was used to simulate the propagation characteristics of electromagnetic waves emitted by a circular antenna in coal(rock)layers encountering different types of geological anomalies(faults,collapse columns)under full-space conditions.The following conclusions were obtained:when the geological anomaly is predominantly filled with air,the electromagnetic wave loss is low,and the contour lines of magnetic field intensity protrude outside;while filled with water,the electromagnetic wave energy loss is greater and the curves are concave;when filled with other media,the loss is between the two extremes,and the electrical characteristics of the anomaly area can be determined by observing the changes in field strength curves and contour lines.Different shapes and sizes of geological anomalies lead to various magnetic field intensity.When the anomaly area is circular or approximately circular,the magnetic field intensity is distorted within the anomalous body and gradually returns to a normal distribution away from the anomaly,making identification more difficult;the smaller the diameter of the anomalous body,the more challenging the identification becomes.When the anomaly area consists of a linear fault,the angle between the fault direction and the tunnel affects the number of affected measurement points,making identification easier when the angle is small;as the angle increases,fewer measurement points are affected,making identification more difficult,and the fault direction can be roughly determined with this observation.Under normal circumstances,the field strength curve is a symmetrical parabola with the intensity maximizes at the middle and gradually decreases along both sides.However,the shape of the curve varies depending on the position,morphology,and filling material of the anomalous body.When the anomalous body is large,the curve is a symmetrical or asymmetrical"M"shape.Therefore,in the initial stage of data processing,the qualitative characteristics of anomalous bodies can be preliminarily determined according to the curve shape.However,precise localization of anomalous features along the ray requires further analysis using tomographic imaging to achieve a correct and reasonable understanding.
radio penetration methodnumerical simulationcollapse columnfault
NETL
NSTL
万方数据
