METHODICAL ASPECTS OF DETERMINATION OF THERMOBARIC EFFECTS ON ULTRASONIC VIBRATION VELOCITY IN ROCKS

Estimation of stresses in rock mass by ultrasonic techniques based on measurement of P-wave velocities is incompetent due to poor correlation of the latter and the level of mechanical stresses. On the other hand, addition of temperature in ultrasonic measurement can considerably improve sensitivity of in-situ testing. This article is devoted to the methodical aspects of determination of elastic P-wave velocities as function of pressure and temperature in laboratory tests of rock specimens. The basic approaches to obtaining such relationships are the measurement of the velocity–stress characteristic at fixed temperatures and the measurement of the velocity–temperature characteristic at fixed levels of mechanical loading. The second approach is more laborious and results in no accumulation of microdefects in a specimen. It is important to control and maintain thermal equilibrium in a specimen (equal temperatures in the center and on the surface). Indirect estimability of achieving such equilibrium by the flattening of P-wave velocity recorded in the course of heating is experimentally proved. Specific attention is paid to the post-treatment of the obtained three-dimensional relationships. It is proposed to present them in the form of a family of curves and 3D surfaces. The latter are possible to obtain using a polynomial regression (for estimation of general trend), or by interpolation by the Shepard or Kriging methods. The article exemplifies evaluation of uniaxial mechanical stress by the measured values of velocity and temperature and using the known three-dimensional relationship.

Acknowledgements: The study was supported by the Russian Foundation for Basic Research, Agreement No. 19-05-00152\19.

For citation: Nikolenko P. V. Methodical aspects of determination of thermobaric effects on ultrasonic vibration velocity in rocks. MIAB. Mining Inf. Anal. Bull. 2019;(9):160-167. [In Russ]. DOI: 10.25018/0236-1493-2019-09-0-160-167.

Keywords

Thermobaric effects, rocks specimens, Peltier effect, ultrasound, control, stress state.

Issue number: 9
Year: 2019
ISBN: 0236-1493
UDK: 622.02:539.2
DOI: 10.25018/0236-1493-2019-09-0-160-167
Authors: Nikolenko P. V.

About authors: Nikolenko, Cand. Sci. (Eng.), Assistant Professor, e-mail: petrov-87@mail.ru, National University of Science and Technology «MISiS», 119049, Moscow, Russia.

REFERENCES:

1. Rzhevskiy V. V., YAmshchikov V. S. Akusticheskie metody issledovaniya i kontrolya gornykh porod v massive [Acoustic methods of research and control of rocks in the massif], Moscow, Nauka, 1973, 224 p.

2. Turchaninov I. A., Panin V. I. Geofizicheskie metody opredeleniya i kontrolya napryazheniy v massive [Geophysical methods for determining and monitoring stresses in the massif], Leningrad, Nauka, 1976, 163 p.

3. Mambetov SH. A. Geoakusticheskiy kontrol' sostoyaniya massiva gornykh porod vblizi gornykh vyrabotok [Geoacoustic control of the state of the rock mass near the mine workings], Frunze, Ilim Геоакустический контроль состояния массива горных пород вблизи горных выработок. Фрунзе, Илим, 1978, 172 p.

4. Danilov V. N., SHkuratnik V. L., Sirota D. N. The relationship between acous-tic characteristics and stresses in the rock mass. Izvestiya vuzov. Gornyy zhurnal. 1988, no 2, pp. 1—6. [In Russ].

5. Shea V. R. Elastic wave velocity and attenuation as used to define phases of loading and failure in coal. International Gournal of Rock Mechanics and Mining Sciences, 1988, Vol. 25, no 6, pp. 431—437.

6. Ostadhassan M., Tamimi N. Mechanical behavior of salt rock at elevated temperature. 48th US Rock Mechanics / Geomechanics Symposium, 2014, Vol. 3, pp. 1473—1480.

7. Chryssanthakis P., Westerdahl H., Rose E., Rhett D., Pederson S. High temperature triaxial tests with ultrasonic measurements on Ekofisk chalk / 20th Century Lessons, 21st Century Challenges, 1999, pp. 573—578.

8. Volarovich M. P. The investigation of elastiс and absorption properties of rocks at high pressures and temperatures. Tectonophysics, 1965, Vol. 2, no 2—3, pp. 211—217.

9. Spravochnik po fizicheskim svoystvam mineralov i gornykh porod pri vysokikh termodinamicheskikh parametrakh. Pod red. M. P. Volarovich [Handbook of physical properties of minerals and rocks at high thermodynamic parameters. Volarovich M. P. (Ed.)], Moscow, Nedra, 1978, 265 p.

10. Zhang R.-R., Jing L.-W., Ma Q.-Y. Experimental Study on Thermal Damage and Energy Evolution of Sandstone after High Temperature Treatment. Shock and Vibration, 2018, Vol. 2018, Article number 3845353.

11. Shkuratnik V. L., Nikolenko, P.V., Koshelev A. E. Stress dependence of elastic P-wave velocity and amplitude in coal specimens under varied loading conditions. Journal of Mining Science, 2016, Vol. 52, no 5, pp. 873—877.

12. Brotóns V., Ivorra S., Tomás R. Correlations between static and dynamic elastic modulus of a calcarenite heated at different temperatures. Rock Engineering and Rock Mechanics: Structures in and on Rock Masses — Proceedings of EUROCK 2014, ISRM European Regional Symposium, pp. 143—148.

13. Vavilin V., Kolpakov V., Romanov Y., Kunakasov A., Urazgulov R. Strength properties, elastic modules and compressibility factors of rocks from oil fields LUKOIL-western Siberia. Society of Petroleum Engineers — SPE Russian Petroleum Technology Conference and Exhibition, 2016, pp. 2469—2489.

14. Vinnikov V. A., Voznesenskii A. S., Ustinov K. B., Shkuratnik V. L. Theoretical models of acoustic emission in rocks with different heating regimes. Journal of Applied Mechanics and Technical Physics, 2010, Vol. 51, no 1, pp. 84—88.

15. Nikolenko P. V., Nabatov V. V. Interference protection in geoacoustic control of critical stresses in rocks. Gornyi Zhurnal, 2015, Vol. 2015, no 9, pp. 33—36.

16. Yao M., Rong G., Zhou C., Peng J. Effects of thermal damage and confining pressure on the mechanical properties of coarse marble. Rock Mechanics and Rock Engineering, 2016, Vol. 49, no 6, pp. 2043—2054.

17. Nikolenko P. V., Shkuratnik V. L. Laboratory setup for ultrasonic testing of rock samples in variable temperature and pressure conditions. MIAB. Mining Inf. Anal. Bull. 2019;5:89-96. [In Russ]. DOI: 10.25018/0236-1493-2019-05-0-89-96.

18. Shepard D. A two dimensional interpolation function for irregularly-spaced data. ACM National Conference, 1968, pp. 517—524.

19. Oliver M. A. Krigging. A method of interpolation for geographical information systems. International journal of geographic information systems, 1990, Vol. 4, pp. 313—332.