The Technology And Application Of Mine Full-space Transient Electromagnetic Detection By Small Coil

Transient electromagnetic method (TEM) is able to penetrate the high resistance shielding layer, it has a good distinguish ability to water conducted structure or containing water of overlying strata under the high resistance shielding, the results is very intuitive. This method is more applications in recent years, but the detecting depth and the multi-solution explanations constraint its development in the safety production of coal mine. This thesis carry out TEM full-space theory and the application technology research under the support of major national science and technology program "fissure distribution measurement technology and equipment project". This study has important theoretical significance and practical application value on improving sounding effect of mine TEM.This thesis started from basic theory of TEM, arrangement the formula of predecessors, founded that the full-space and half-space of TEM has certain relations, presented the multiple phenomenon of mine TEM; put forwarded the characteristic coal mining work-face detection "intersection method". This can effectively avoid false anomaly, and better detects water of return exploitation coal mining work-face; This thesis studied the detection depth problem of small coil TEM in the coal mine, and put forward the depth estimation formula of full-space TEM; Proved the correctness and feasibility of this theory and method though a large number of experimental data.This research obtained the following results:(1) This thesis researched the full-space TEM field and half-space TEM field, put forwarded TEM multiple phenomenon, arrangement and extended the related formula of full-space TEM theory, compared the related parameters of full-space TEM field and half-space TEM field. In the end, it is concluded that the magnetic field intensity of full-space TEM is2.5times of half-space TEM field in the late, that is multiple phenomenon of mine TEM, and furthermore, obtained the calculation formula of apparent resistivity that applied in the mine TEM detection, put forwarded the calculation coefficient principle of mine TEM apparent resistivity. The multiple phenomenon of mine TEM shows that the application of full-space TEM theory in the actual detection improved signal noise ratio and increased the detecting depth. In addition, due to the half-space TEM field is relatively mature in theory and has more reference material in practice, calculation of mine TEM field in the late can use multiples phenomenon to get a corresponding conclusion. This has a very important reference value in actual exploration project applications.(2) Based on the multiples phenomenon of mine TEM, this thesis put forwarded that the mine TEM depth estimation formula is dm=Kdm(IA/σηv)1/5On the basis of previous studies, this thesis continues studied the depth estimation formula of half-space TEM and full-space TEM, deduced the depth estimation formula of mine TEM, and put forwarded the view that the full-space probing depth is greater than half-space; Based on this view, this thesis discussed the feasibility of mine TEM in depth. It is concluded that the mine TEM can meets the requirements of the water detection within100meters.(3) This thesis research the mine TEM technology, put forwarded low resistivity abnormally "intersection method" of coal mining working detecting. Research results show that this method can effectively avoid false abnormal, and better detect containing water of working face; Drawn through the simulation of different geological models, mine TEM reaction of low resistivity aquifer obvious, less obvious body of high impedance moisture content, low resistivity response corresponding induced voltage performance for high-potential, high resistivity response corresponding to the induced voltage is expressed as the low potential;In the light of coal mine special underground environment and limited tunnel space, this research designed the TEM underground working method:fixed translation method、angle conversion method and comprehensive method; Through studying on influencing factors of underground, this thesis concluded that underground tunnel effect can not be ignored; through a lot of practice, concluded the underground technology and safety measures. Such preliminary formed relatively complete TEM underground data acquisition method.(4) This thesis researched the observational parameters of the mine TEM and pointed out the principle of the parameters selection of the underground TEM. Research results indicated that the appropriate size of the TEM line frame for the mine should choose1.5m, the shape of wireframe should choose square, and the selection of the exploration frequency general is25Hz. The principle of the parameter selection is the relative smooth abnormal curves when measures and not have big difference with the theoretical curves.(5) The thesis researched the mine TEM interpretation software and three-dimensional (3D) visualization based on the mine TEM multiple phenomenon and probing depth theory. Research results shows that the mine TEM interpretation method is easier to use the interpretation of layer simulation method; the mine TEM data processing system that using multiple phenomenon and probing depth theory to write is better adapted to the actual detection needs. Surfer image processing method use linear interpolation of "triangulation" method in TEM coil hit angle, use "Kriging" method in without the play point, this would avoid some false anomaly generation; the Voxler software can be used to mine TEM3D visualization research, and the results is good, detection results is stereoscopic display, this makes the detection results is more intuitive and easy analysis.(6) This thesis validated the correctness and feasibility of the proposed views through a lot of practice test of TEM. Research results show that detection of underground examples proved the correctness of the detection results using "intersection method", this method greatly improves detection accuracy and reduce drilling workload. The TEM anomaly interpretation principle, TEM tracking detection method and coal mine water conducted zone detection method is feasible by practice. Application of the theory and method presented in this thesis, to detected TEM for a mine, success rate is86.2%, and this better explain the correctness of combination of theory and practice.