Research On Imaging Methods And Application Of Reflected In-seam Wave At The Roadway Lateral Wall Of Coal Seam

The technology of in-seam transmission method underground coal mine is more mature.However,the reflected in-seam wave exploration technology is still developing.The research of reflected in-seam wave is less at home and abroad.The use of one roadway lateral walls to carry out detection of internal geological conditions on both roadway sides of working faces is the urgent need to solve the technical problems.In this paper,the three-dimensional in-seam wave forward modeling technology underground coal mine is carried out.Four models including typical geologic anomalies are designed to simulate the reflected in-seam wave.The wave field characteristics and propagation laws of the reflected in-seam wave are analyzed.The ?-p filtering,radial path transform,polarization filtering and other technologies of reflected in-seam wave denoising techniques are developed,and the energy compensation enhancement technique of reflected in-seam wave is also developed.This paper focuses on studying a variety of migration methods suitable for reflected in-seam wave imaging.Various migration methods are tested using theoretical simulation datas.Combined with the actual project,the effect of reflected in-seam wave migration methods is tested.The main results are as follows:(1)The numerical simulation of three-dimensional in-seam wave including roadway based on personal computer is realized.The staggered-grid high-order finite difference method and PML absorption boundary algorithm are used to simulate the three-dimensional in-seam wave.Three-dimensional roadway boundary processing algorithm is designed which can better simulate the in-seam wave of three-dimensional coal seam with roadway.(2)The numerical simulation of four reflected in-seam wave models with typical geological anomalies is carried out.The energy of the fundamental mode reflected in-seam wave is strong which can be used to detect faults.The reflected in-seam wave of the collapse column is very weak,and it is more difficult to perform the migration imaging.For the model including faults on both sides of the roadway,the energy of the reflected in-seam wave generated by the fault across the roadway is very small.(3)The data processing technologies of reflected in-seam wave are realized.?-p filter method can be used to remove direct waves,roadway head diffraction in-seam wave and so on.When the actual data is poor,the method of radial path transformation is used to suppress the direct in-seam wave and sound wave.Reflected in-seam wave field separation can be done by Poline polarization filtering method.The least squares deconvolution method compresses the actual reflection in-seam wave.(4)A variety of reflected in-seam wave migration imaging methods are realized,and the numerical simulation datas are imaged used these methods.Love-type in-seam wave polarization migration imaging is the best.There is a difference in the effect of different component diffraction.Diffraction migration imaging and scattered wave imaging have advantages and disadvantages for different geologic imaging.(5)The influence of the existence of faults on both sides of the roadway,the anti-noise of the imaging methods and the feasibility of using the P-wave S-wave detection are analyzed.Innovations:(1)Three-dimensional high-order staggered-grid finite difference technique is used to realize the three-dimensional reflected in-seam wave simulation.(2)According to the difference of polarization characteristics between Rayleigh type and Love type in-seam wave,in-seam wave polarization migration imaging based on in-seam wave polarization characteristics is proposed for the first time.(3)A variety of reflected in-seam wave offset imaging methods are compared and analyzed.It is considered that Love type in-seam wave polarization migration imaging is the best,and the scattering wave imaging has the potential of development.