The Experimental Study On Appliying Double Frequency Induced Polarization Method Detecting Coal Mine God

Coal resources are one of the most important energy resources. The exploiting of coal resources on a large scale can bring about not only financial and social interests, but also a lot of loss to the environment and people's lives. The underground mining of the colliery and sinking area on the surface of the ground due to mining underground will influence the production and life of the local people, and undermine the continual development of the local economy. It can even affect the relationship between the mines and the local people, thus becoming unstable factors of our society.Double frequency induced polarization method put forward and realized by Professor He jishan-China engineering council academician of Central South University in the 20th century 1970s.It is a unique method put forward by Chinese and instrument invested by Chinese in geophysics region and a kind of frequency domain geophysical exploration method. The successful application of Double frequency induced polarization method in prospecting mineral,ground water and so all, lead to our attempting to detecting underground gob by this way. Firstly,the paper summarized the applied research present status of induced polarization method,analysed the relative merits of the different kinds of geophysical method detecting gob,and put forward the viewpoint of detecting gob using double frequency induced polarization method. The paper preliminarily analyzed the morphological characteristics of the gob,the apparent resistivity and the apparent amplitude-frequency rate. The author mainly discussed the amplitude-frequency rate. After the underground coal being stopen out,the induced polarization characteristic of the coal is greatly weaken. As a result,the small area of induced polarization characteristic value formed in the district of high induced polarization characteristic value supplys physical condition for detecting the gob using the induced polarization characteristic of the coal . Based on theoretical analysis,the author find out it is different to differ scale gob apparent resistivity and apparent amplitude-frequency rate rate characteristic. So far as large area gob,its abnormal value should be high and wide scope apparent resistivity,and lower and wider scope apparent amplitude-frequency rate;the small kiln gob is distributed messily and little practical gob area. So far as nonswimming gob,its abnormal value should be high apparent resistivity,while swimming gob,its abnormal value should be low apparent resistivity,and lower apparent amplitude- frequency rate;So far as age-old gob,because of its formed time long,distributed messily and little practical gob area,nonswimming gob'abnormal value should be high apparent resistivity,while swimming gob'abnormal value should be low apparent resistivity,its abnormal low apparent amplitude- frequency ratethe age-old gob is formed long ago, distributed messily and small area,reflecting for the high apparent resistivity when the gob was not full of water and the low apparent resistivity when the gob was full of water in the apparent resistivity sectional drawing and the low apparent amplitude-frequency rate in the apparent amplitude-frequency rate sectional drawing, but the abnormal value is smaller than both of gob value.Secondly,the paper approximately considered the small kiln gob as sphere or tabular body,analyzed some kind of electric anomaly characteristic that may existent in detecting the small kiln gob using double frequency induced polarization method-middle gradient method and double-dipole method;put experimentation on detecting gob in the given small kiln gob.By data reduction and analyses,detective gob position basically agrees with given production data,which manifest it is feasible and worthwhile to applying double frequency induced polarization method detecting coal mine gob.Lastly,the paper analyzed different kinds of interference factor encountering on the experiment and put forward both measure and means which avoid and overcome different kinds of interference factor,which supplys precious experience for specific enforcing detecting underground gob using double frequency induced polarization method.