National University of Science and Technology MISIS, Moscow, Russia:

V. L. Shkuratnik, Professor, Doctor of Engineering Sciences, ftkp@mail.ru
P. V. Nikolenko, Associate Professor, Candidate of Engineering Sciences
A. A. Kormnov, Post-Graduate Student

The experimental research findings allow determining mechanisms of change in the correlation characteristics of acoustic noise in sonic tests of rock salt specimens under uniaxial mechanical loading. The interconnection between these characteristics and stages of deformation is shown for the events of coincident and orthogonal orientations of loading and sonic testing. It is emphasized that the transition from the elasto-plasticity to plastic stage of limit deformation is accompanied by the abnormally high change in the related informational parameters of the correlation control and by the inversion of sign of this change. It is suggested to use this mechanism in prediction of impendent rock failure. The comparative assessment is given for the influence of stresses on such informational control parameters as dispersion and autocorrelation function period, and coefficient and correlation window of cross-correlation function of received signals. It is noticed that the use of continuous noise signals rather than traditional impulse signals enables considerable reduction in amplitude of transmitting acoustic transducer voltage and, thus, simplifies engineering of spark- and explosion-proof ultrasonic control equipment. In terms of the experimental estimate of condition of rib pillars, it is found that the ultrasonic control method in the real-time crosshole sonic testing regime makes it possible to obtain data on spatial stress distribution in rocks around underground excavations. The article shows that the measure of discrepancy of acoustic noise in the zones of relaxation, in situ stress and abatement pressure is much higher than the same differences in the elastic P-wave velocities conventionally used in geo-control. This fact conditions efficiency of informational correlation parameters in determining occurrence depth of abatement pressure zone maximum and its displacement upon increased damage of adjacent rock mass.
The study has been supported by the Ministry of Education of the Russian Federation in the framework of state assignment No. 2014/113, Project No. 504.

1. Kurlenya M. V., Mirenkov V. E., Shutov V. A. Osobennosti deformirovaniya porod v okrestnosti vyrabotki na bolshikh glubinakh (Rock deformation around stopes at deep levels). Fiziko-tekhnicheskie problemy razrabotki poleznykh iskopaemykh = Journal of Mining Science. 2014. No. 6. pp. 4–10.
2. Khmelevskoy V. K., Kostitsyn V. I. Osnovy geofizicheskikh metodov: uchebnik dlya vuzov (Geophysical method basis: tutorial for universities). Perm : Perm university, 2010. 400 p.
3. Ermolov I. N. Teoriya i praktika ultrazvukovogo kontrolya (Theory and practice of ultrasonic control). Moscow : Mashinostroenie, 1981. 240 p.
4. Li Q., He J.-J., Li C.-X. Relationship between the ultrasonic velocities and strata pressure of the coalbed methane reservoir in qinshui basin by rock physical testing. Wutan Huatan Jisuan Jishu. 2013. Vol. 35, Iss. 4. pp. 382–386.
5. Bobrenko V. M., Kutsenko A. N., Rudakov A. S. Akusticheskaya tenzometriya (Acoustic tensometry). Kontrol. Diagnostika = Testing. Diagnostics. 2001. No. 4. pp. 23–29.
6. Yamshchikov V. S., Nosov V. N. K obosnovaniyu ultrazvukovogo korrelyatsionnogo metoda defektoskopii krupnostrukturnykh materialov (Substantiation of ultrasonic correlation method of large-structure material defectoscopy). Defektoskopiya = Russian Journal of Nondestructive Testing. 1972. No. 3. pp. 39–44.
7. Yamshchikov V. S., Nosov V. N. Vybor informativnykh parametrov pri statisticheskikh metodakh defektoskopii krupnostrukturnykh materialov (Choice of information parameters with statistic methods of large-structure material defectoscopy). Defektoskopiya = Russian Journal of Nondestructive Testing. 1974. No. 4. pp. 24–29.
8. Shkuratnik V. L., Nikolenko P. V., Kormnov A. A. Ultrasonic correlation logging for roof rock structure diagnostics. Journal of Mining Science. 2015. Vol. 51, Iss. 3. pp. 456–461.
9. Shkuratnik V. L., Nikolenko P. V., Kormnov A. A. Otsenka chuvstvitelnosti metoda ultrazvukovogo korrelyatsionnogo karotazha pri vyyavlenii treshchin v krovle gornykh vyrabotok (Estimation of ultrasonic correlation logging sensitivity in crack detection in excavation roof). Gornyi Zhurnal = Mining Journal. 2016. No. 1. pp. 54–57.
10. Shkuratnik V. L., Novikov E. A. Influence of the mechanical loading of rock salt on the parameters of thermoacoustic emission. Journal of Applied Mechanics and Technical Physics. 2015. Vol. 56, No. 3. pp. 486–493.
11. Bendat J. S., Piersol A. G. Engineering Applications of Correlation and Spectral Analysis. 2th edition. Wiley, 1993. 472 p.
12. Shkuratnik V. L., Nikolenko P. V., Kormnov A. A. Characteristics of instrumental support of structural heterogeneity control around mining using noise probing signals. Sbornik nauchnykh trudov Natsionalnogo Issledovatelskogo Tekhnologicheskogo Universiteta «MISiS» (Collection of scientific proceedings of National University of Science and Technology “MISiS”). Moscow, 2015. pp. 60–65.
13. Morcote A., Mavko G., Prasad M. Dynamic elastic properties of coal. Geophysics. 2010. Vol. 75, Iss. 6. pp. E227–E234
14. Shkuratnik V. L., Nikolenko P. V., Kormnov A. A. O printsipakh ultrazvukovoy strukturnoy diagnostiki prikonturnogo massiva s ispolzovaniem shumovykh zondiruyushchikh signalov (About the principles of ultrasonic structure diagnostics of border massif using noise emission pulses). Gornyy informatsionno-analiticheskiy byulleten = Mining Informational and Analytical Bulletin. 2015. No. 1. pp. 53–62.