Regular patterns of acoustic activity, axial and volumetric strains in rock salt under Karman’s loads and thermal effects

Synchronous measurements of acoustic emission and deformation were carried out on rock salt samples subjected to complex stress under three different levels of the external thermal forces. The measurement instrumentation and procedures are described. The features of acoustic emission are revealed for each deformation stage and specific temperature. It is found that in the tests according to Karman’s scheme, the acoustic activity at each deformation stage changes more orderly than under uniaxial loading, which is connected with structural consolidation of the geomaterial. As against the axial and volumetric straining, the acoustic activity experiences sharp changes at the boundaries between the deformation stages. This provides sufficient distinction of the boundaries, assessment of the related physical and mechanical properties of rock salt and identification of its deformation stages. The increase in the test temperature caused some displacement of the boundaries between the linearly elastic and elastoplastic stages of deformation as well as between the stages of elastoplasticity and failure. This displacement corresponds to the decrease in the elastic limit and ultimate longterm strength in each sample of rock salt with increasing temperature relative to the ultimate compression strength.

Kravchenko O. S. Regular patterns of acoustic activity, axial and volumetric strains in rock salt under Karman’s loads and thermal effects. MIAB. Mining Inf. Anal. Bull. 2020;(4):96-104. [In Russ]. DOI: 10.25018/0236-1493-2020-4-0-96-104.

O.S. Kravchenko, Graduate Student, e-mail: ftkp@mail.ru, National University of Science and Technology «MISiS», 119049, Moscow, Russia.

1. Zubov V. P., Kovalski E. R., Antonov S. V., Pachgin V. V. Improving the safety of mines in developing Verkhnekamsk potassium and magnesium salts. MIAB. Mining Inf. Anal. Bull. 2019;5:22-33. [In Russ]. DOI: 10.25018/0236-1493-2019-05-0-22-33.

2. Mansouri H., Ajalloeian R. Mechanical behavior of salt rock under uniaxial compression and creep tests. International Journal of Rock Mechanics and Mining Sciences. 2018. Vol. 110, pp. 19—27.

3. Li H., Yang C., Zhao W., Liu B., Yin X. Experimental studies of failure characteristics and evolution laws of ultrasonic velocity and acoustic emission for salt rock under triaxial loading. Rock and Soil Mechanics. 2016. Vol. 37, pp. 2458—2466.

4. Filimonov Y., Lavrov A., Shkuratnik V. Acoustik emission in rock salt: effect of loading rate. Strain, 2002. Vol. 38, pp. 157—159. DOI:10.1111/j.1475-1305.2002.00022.x.

5. Filimonov Y. L., Lavrov A. V., Shafarenko Y. M., Shkuratnk V. L. Experimentelle untersuchung steinsalzes mittels einaxialem drucktest mit hydrostatisher vorbelastung. GlueckaufForschungshefte. 2002. Vol. 61, pp. 80—83.

6. Novikov E.A., Oshkin R. O., Shkuratnik V. L., Epshtein S.A., Dobryakova N. N. Application of thermally stimulated acoustic emission method to assess the thermal resistance and related properties of coals. International Journal of Mining Science and Technology. 2018. Vol. 28, No 2, pp. 243—249.

7. Lavrov A. V., Filimonov Yu. L., Shkuratnik V. L. Kaiser effect in rock salt.Fizikotekhnicheskiye problemy razrabotki poleznykh iskopayemykh. 2002, no 5, pp. 40—48.

8. Vinnikov V.A., Voznesenskiy A. S., Ustinov K. V., Shkuratnik V. L. Theoretical models of acoustic emission in rocks with different heating regimes. Prikladnaya mekhanika i tekhnicheskaya fizika. 2010. Vol. 51(1), pp. 100—105. [In Russ].

9. Li H., Yang C., Zhao W., Liu B., Yin X. Experimental studies of failure characteristics and evolution laws of ultrasonic velocity and acoustic emission for salt rock under triaxial loading. Yantu Lixue/Rock and Soil Mechanics, 2016. Vol. 37, No 9, pp. 2458—2466.

10. Jie C., Junwe, Z., Song R., Lin L., Liming, Y. Determination of damage constitutive behavior for rock salt under uniaxial compression condition with acoustic emission. Open Civil Engineering Journal. 2015. Vol. 9, No 1, pp. 75—81.

11. Mejia F., Shyu M.-L., Nanni A. Data quality enhancement and knowledge discovery from relevant signals in acoustic emission. Mechanical Systems and Signal Processing, 2015, Vol. 62, pp. 381—394.

12. Nikolenko P. V., Nabatov V. V. Interference protection in geoacoustic control of critical stresses in rocks. Gornyi Zhurnal. 2015, no 9, pp. 33—36. [In Russ].

13. Shkuratnik V. L., Kravchenko O. S., Filimonov Yu. L. Stresses and temperature affecting acoustic emission and rheological characteristics of rock salt. Fiziko-tekhnicheskiye problemy razrabotki poleznykh iskopayemykh. 2019, no 4, pp. 20—27. [In Russ].