The Research And Application Of3D DC Resistivity Inversion In Coal Mine

At present, the higher coal group in some major coal production bases in our country isrunning out, thus the mining of lower coal group in large scale is badly needed. However, thedistance between lower coal group and rich aquifer-namely ordovician limestone-is ratherlimited, which is approximately30m. And water inrush from ordovician limestone to themine through some vertical hydraulic conductivity channel-fault, collapse column, fracture-is a common cause of extremely serious mine water damage in addition to water inrush fromold empty area. Therefore, detecting of vertical coal seam containing or conducting waterstructure whlie mining with pressure is particularly important.From the differential equations satisfying the full potential of the whole space, this paperstudies the point source field potentials and abnormal point boundary value problem, appliesthe seven point finite difference method solve the three dimensional electric field problem andacquires the approximate ground potential distribution. Then this paper carries out the3Delectrical forward simulation, analyzes the recognition accuracy of different detection methodson the water conducting channel, and put forward the improvement of existing device layoutand line layout mode, that is the parallel dipole-dipole observation data collecting device ismore suitable for3D direct current in mine. The RESINVM3D software has been improved,and the objective function is constructed according to the actual geological conditions. By theinversion imaging method, this paper determines the prior condition of the highest inversion isthe regularization parameter for10and the weight parameters for1/z, the results of some examples are in good agreement with the known geological conditions through3D inversionimaging.Though the study on the forward/inversion technique of the electric model of the typicalcontaining (guide) water structure, this paper realizes the stereo imaging of vertical guidewater channel such as faults, fissures and collapse columns, and provides the technical supportto judge the inrush possibility of the concealed containing (guide) water structure.