The great leader Comrade
"Scientists and technicians should work to overcome by their own efforts the problems which require an urgent solution for the development of the national economy of our country, and to introduce the scientific and technical successes of developed countries in accordance with its specific reality."
To exactly predict ore body ahead of the tunnel face in the coal mines and mines is very important for reducing false tunnel drilling and the cost. Also to predict geologic body such as caves, faults, erratic rocks, fractured zones and aquifers in tunnel construction related to infrastructure construction in urban areas, larger traffic development projects and water passageway construction of hydroelectric power stations is important way for reducing a danger to humans and machines and tunnel construction costs.
For prediction of geologic body ahead of the tunnel, non-destructive geophysical techniques as well as prospecting by drilling are efficient tools.
We have established a method to analyze frequency domain induced polarization (IP) data due to anomolous body ahead of the tunnel face using the reverse pole-dipole array with multi-electrodes.
Firstly, by synthetically analyzing apparent resistivity and Percent Frequency Effect (PFE) due to the plate and sphere ahead of the tunnel, we determined numbers of terms of infinite series in formulas of forward modeling to use for joint inversion of apparent resistivity and frequency domain IP data in the tunnel. Existence of anomalous body ahead of the tunnel face can be predicted using extreme on the apparent resistivity curve and inversion models of data measured using the reverse pole-dipole array with multi-electrodes.
We have carried out joint inversion with positivity constraint using logarithmic barrier method.
Reliability of the method was verified through tests with synthetic data.
Accuracy of joint inversion is higher when the number of current electrodes is increased and when the ratio between length of survey line and the distance from the tunnel face to the anomalous body is greater than three times. Table shows the inversion models and relative model error according to the number of current electrodes for the plate model.
This method is published by the title of "A study of joint inversion of self-potential (SP) and magnetic anomalies in the geophysical prospecting" (http://www.ajer.org/papers/Vol-8-issue-6/A08060107.pdf) of "American Journal of Engineering Research".
Table. Joint inversion models according to the number of current electrodes