Kharisov T. F., Panzhin A. A., Kharisova O. D. Some problems of the express method of rock strength determination. Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal = News of the Higher Institutions. Mining Journal. 2019; 7: 86–91 (In Russ.). DOI: 10.21440/0536-1028-2019-7-86-91

Introduction. Within the course of mining, rock massif heterogeneity calls for constant operational control of its changing state and characteristics. One key parameter of the massif under investigation is the compressive strength. Main way of rock strength properties determination currently is laboratory testing of the prepared samples by means of presses. One alternative way of geomaterials’ compressive strength on-line measurement is the method of elastic rebound with a sclerometer (Schmidt’s hammer).
Research methodology. Research object are rocks of Dzhetygarinsky pit surface massif where hand specimen were selected for testing. Compressive strength was determined by the main method and the alternative method.
Research results. Laboratory research results at presses have shown some discrepancy between the obtained values and Schmidt’s hammer readout. However, it should be noted that the results obtained in the laboratory conditions are the most exact and reliable. Data discrepancy is caused by the presence of structural and textural inhomogeneity of the hard rock under investigation. Comparative analysis and statistical data processing for various types of rock at Dzhetygarinsky massif determined calibration curves and distinguished the transition coefficients of compressive strength from sclerometer readout to laboratory values.

Key words: compressive strength; Schmidt’s hammer; sclerometer; massif; samples; hand specimen; laboratory research.

REFERENCES

1. 1. Zhabko A. V. Stability analysis for inhomogeneous and nonisotropic slopes. Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal = News of the Higher Institutions. Mining Journal. 2014; 3: 22–29. (In Russ.)
2. Efremov E. Iu., Panzhin A. A., Kharisov T. F., Kharisova O. D. Study of geomechanical conditions at Kiembaevsky open pit and potentially hazardous areas detection. Vestnik Natsionalnoi akademii gornykh nauk = Bulletin of the National Academy of Mining. 2018; 2(3): 42–53. (In Russ.)
3. Kharisov T. F., Kharisova O. D., Efremov E. Iu., Konovalova Iu. P. Research of stability of edges and benches of the Kiyembayevsky field open-pit. Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal = News of the Higher Institutions. Mining Journal. 2018; 5: 30–39. (In Russ.)
4. Sashurin A. D. Geomechanical processes and phenomena determining the safety and efficacy of subsoil use, regularities of their development. Problemy nedropolzovaniia = The Problems of Subsoil Use. 2018; 3(18): 21–31. (In Russ.)
5. Kharisov T. F., Kharisova O. D. Numerical modelling of the rock mass stability in the course of mining in difficult mining-and-geological conditions. In: Design, construction and maintenanceof underground facilities complexes: proceedings of the 6th International conference. Ekaterinburg, 2019. p. 135–143. (In Russ.)
6. Bieniawski Z. T. Engineering Rock Mass Classifications. John Wiley & Sons, New York, 1989. P. 240–250.
7. Laubscher D. H. and Jakubec J. The MRMR rock mass classification for jointed rock masses. In: Underground Mining Methods: Engineering Fundamentals and International Case Studies (eds. W. A. Hustrulid & R. L. Bullok). Society of Mining Metallurgy and Exploration, SME. 2001. P. 475–481.
8. Hoek E., Kaiser P. K. and Bawden W. F. Support of Underground Excavations in Hard Rock. Balkema, Rotterdam, 1995. P. 91–105.
9. Prokopov A. Iu., Gergart Iu. A. Testing and accuracy evaluation of the nondestructive express method of rock mass strength properties determination in the conditions of Rokksky tunnel reconstruction. Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal = News of the Higher Institutions. Mining Journal. 2015; 4: 101–107. (In Russ.)
10. Kartashov S. A., Prokopov A. Iu. The use of the express method of hard rock strength control when driving tunnels. In: Innovation process monitoring mechanisms of: proceedings of the International research-to-practice conference. Ufa, 2017. P. 55–57. (In Russ.)
11. Wu B., Xia K. Dynamic brazilian test on laurentian granite under pre-stress conditions. Vestnik Inzhenernoi shkoly Dalnevostochnogo federalnogo universiteta = The FEFU: School of Engineering Bulletin. 2016; 2(27): 3–9.
12. Usoltseva O. M., Semenov V. N., Serdiukov S. V., Rybalkin L. A. Laboratory studies of coal samples. problems of core recovery. Gornyi informatsionno-analiticheskii biulleten (nauchno-tekhnicheskii zhurnal) = Mining Informational and Analytical Bulletin (scientific and technical journal). 2018; S48: 234–242. (In Russ.)
13. Kalachev V. A., Zaitsev D. V., Kochanov A. N., Kostandov Iu. A., Panfilov P. E. Effect of water on fracture of rocks under diametral compression. Fundamentalnye i prikladnye voprosy gornykh nauk = Journal of Fundamental and Applied Mining Sciences. 2017; 4 (2): 53–57. (In Russ.)

Received 27 May 2019