The Appliance Research Of Integrated Geophysical Techniqueson The Detection Of Colliery Gob

In the background of coal mine goaf detection, this paperresearch in comprehensivegeophysical exploration, combining the High Density Resistivity method and Time DomainTransient Electromagnetic method.Through forward numerical simulation technology, based onthe characteristics of each type of geophysical prospecting methods in using different devices anddifferent parameter Settings, the typical geoelectric modelwas established for numericalsimulation,then the forward modeling datawas got.Inversion resultsand the geological profileareobtained by inversion calculation software, comparing and analyzing the inversion results and theactual geoelectric model, finally it is to concluded that the best combination of detecting coal minegoaf.According to the characteristics of the coal mine goaf, researching in the inversion resultsand the actual geoelectric model of High-Density electrical method, the geoelectric modelwasestablished for the level of low resistance, high resistance, lamellar body and high and lowresistance layer structure.according to the analysis and study, all kinds of divices has high lateralresolution and low vertical resolution, and make anomaly center driftdown.the size of geologicalbodyimpact on the resolution is larger, the smaller of the geological body, the error of detectionresultsis greater.Wenner device is one of the most commonly used device, but is insensitiveinreflectingfor small size of the geological body. With the bigger of geologic body, the effect ismore obvious, but reflect anomaly scope are much larger than the actual geologicbody.Dipole-Dipole device is the best device, both on high resistance and low resistance body, itssensitivity is the highest,but detecting depth is small, not suitable for detecting a deepgoaf.Detecting depthof Diode device is the largest, but for geologic bodyof less than a quarter of line length, reflection is not good, when the size is more than a quarter of line length, the effect isgood.But the layoutof distal pole is a difficulty, the demand for work field is high, it is not suitablefor rolling and limited field.The detection effect ofPole-dipole is close to the dipole-dipolein a lot oftime, but the effect is inferior to dipole-dipole, if using the bilateral pole-dipole, its detection effectwill increase a lot.Itis deeper than wenner devicein detection depth, is also a kind of good device.In the researchof Transient electromagnetic method, it has established two typical for threelayersgeoelectric model: K-type and H-type geoelectric model.It is common to use central looptransient electromagnetic device adopts (including overlapping loop) and large fixed source loopdevice.Through numerical simulationof the forward calculationand inversion calculation forgeoelectric model,The final analysis and research show that,comparing central loop (includingoverlapping loop) and the big fixed source device, the central loop has high detection sensitivity,low resistance, high resistance, abnormal responsive, abnormal high coupling, anomalymagnitude, respectively, and is to identify.But it is lowin efficiency, shallow in exploration depth, sois mainly suitable for shallow target.Using large fixed source loop device, it is highinefficiency,which can set a large wire frameone-time, provide greater current, and improve thetransient electromagnetic response.Receives wire frame can be very small, even can make moreturns of coil probes, so it is fast in moving. It also can usemore than onereceivesdevice at thesame time, so the production efficiency is very high.It is weak indetecting thesteep geologicbodies,moreover, will be influenced by volume effect and collecting effect.Using high-density electrical methodof Dipole-dipole device and transient electromagneticmethod of big fixed source loop device,the coal mine goaf was detected.Using high densityresistivity method, stratawithin80meters was detect clearly, the scope of mined-out areawas delimited, after verificationof drilling, it prove that the geophysicalconjectureis correct.Usingtransient electromagnetic method,the mined-out area under200mwas detected, according to thecontour of the fluctuation regularity, the positionof mined-out area wasinferred,after verificationofdrilling, the geophysicalconjecture is correct.In conclusion,using the high density resistivity method and transient electromagnetic method,thecomprehensive geophysicalexplorationis feasibleand effectiveinmine goaf detection.