Advance detection method of rapid excavation based on borehole TEM intelligent stereo imaging

Mining misalignment is one of the major hidden risks of coal mine safe production.Rapid roadway excavation is an important means to ensure the balance of mining and excavation.However,the effective distance of mine geophysical advance detection is short,and the detection accuracy is seriously affected by the complex underground environment,which restricts the speed of roadway excavation.In order to solve the contradiction between exploration and excavation,a long distance drilling transient electromagnetic detection method is proposed which uses directional drilling in front of the excavation work to carry out the detection work.This method can realize single 500 m advance detection on water hazard.In a coordinate system where the drilling direction of the borehole is the positive direction of the Z axis,the right direction of the plane where the orifice is located is the positive direction of the X axis,and the downward direction is the positive direction of the Y axis,the abnormal response patterns of the horizontal component of the drilling transient electromagnetic are all in the form of “sine curve” or “reverse sine curve” form.By the combination of shapes,the quadrant of the anomalous body near the hole can be determined,and the XOY plane rotation angle of the anomalous body is calculated by combining the center deflection angle of the anomalous body synthesized by the horizontal component abnormal field vector.On this basis,considering that each resistivity obtained from the vertical component inversion is an independent anomalous body,the mapping relationship between depth resistivity and sampling time is derived based on the relationship curve between depth calculation coefficient and resistivity,which realizes the one to one correspondence between resistivity and the measuring point and track.The K means clustering algorithm is further used to intelligently locate its distribution quadrant and calculates the XOY plane rotation angle.Then the directional drilling trajectory is used as the rotation axis,and the inclination and azimuth angle of the measuring point are used as the rotation angle to rotate the coordinate space,which realizes the resistivity stereo imaging in the radial direction of the non straight drilling.The three dimensional numerical simulation and the physical simulation results of the water tank are calculated,and the good stereo imaging effects are obtained for the anomalous body in the radial direction of the borehole.Combining with the engineering practice of a coal mine in Shaanxi province,the practicability and effectiveness of the nature,shape and scale of the geological anomaly in front of the heading work were tested by this method for long distance advanced detection ability and precise three dimensional interpretation.The results show that the cluster based transient electromagnetic stereo imaging method for boreholes is an organic combination of geophysics and machine learning.This method can provide a technical support for the advance detection and fine interpretation of hidden water hazards in underground heading faces.In addition,the three dimensional advance detection of long distance transient electromagnetic water hazard in the orientation borehole is carried out before heading,which can effectively ensure the efficient and rapid roadway excavation.