Research on a new method for non-adhesive fixing of rockbolts

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Authors:

I.G.Sаkhno, Dr. Sc. (Tech.), Assist. Prof., orcid.org/0000-0002-8592-0572, State Higher Educational Institution “Donetsk National Technical University”, Pokrovsk, Ukraine, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

S.V.Sаkhno, orcid.org/0000-0003-3917-9143, State Higher Educational Institution “Donetsk National Technical University”, Pokrovsk, Ukraine, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract:

Purpose. Theoretical and experimental evaluation the mechanism of work, bearing capacity and pre-destructive deformations of the anchor system with a new nonadhesive fixing of bolts.

Methodology. The research is conducted through the analytical method, using the base law of classical elasticity theory, and the method of physical modeling. Laboratory tests on the axial load of bolts are made on a real scale on specimens of concrete filled in metal pipes. Three series of models were tested: two series with fixing bolts with self-expanding mixtures, and one series with adhesive fixing. The results are presented as “stress-strain” graphs.

Findings. The range of fluctuation of bearing capacity of “bolt-expanding mixture-rock” system with the change in the main factors is analyzed analytically. The rated bearing capacity of the mentioned system is not less than that of the known energy-absorbing bolts. The mechanism of anchors attached to self-expandable mixtures is determined experimentally. The “load-deformation” curve has rigid and flexible zones, which is characteristic of energy-absorbing bolts. The maximum force of fixing anchors with expanding blends exceeds the effort for bolts fixed by resins more than twice, and the forces in the flexible mode are 67 % larger than the maximum ones in the experiment with fixing Cement KL (Orica) and 99 % more than the UF-MT-15 resin.

Originality. The mechanism of active frictional fixing of anchor bolts by means of compression by mixtures extending in a solid phase in the process of hydration hardening is revealed. The created anchoring system has a high bearing capacity with large pre-destructive deformations. The efficiency of fixing anchor bolts with self-expanding mixture with hydration with the formation of pressure 30‒50 MPa has been proved.

Practical value. The use of research results allows increasing the efficiency of support of roadways by anchoring systems, as well as increasing the stability of rocks at large post elastic deformations.

References.

1. Li, C. C., 2012. Performance of D-bolts Under Static Loading,Rock Mechanics and Rock Engineering, 45, pp. 183–192. DOI: 10.1007/s00603-011-0198-6.

2. Wen, Z. J., Qu, G. L., Wen, J. H., Shi, Y. K.and Jia, C. Y., 2014. Deformation failure characteristics of coal body and mining induced stress evolution law, The Scientific World Journal, 5, pp. 1‒8.

3. Walentek, A. and Lubosik, Z., 2017. Optymalizacja obudowy wyrobisk przyścianowych zlokalizowanych na głębokości większej niż 1000 m. Przegląd Górniczy, 2, pp. 76‒84.

4. Chen, J., Hagan, P. C. and Saydam, S., 2016. Load transfer behavior of fully grouted cable bolts reinforced in weak rocks under tensile loading conditions. Geotechnical Testing Journal, 39(2), pp. 252–263. DOI: 10.1520/GTJ20150096.

5. Wen, Z. J, Jiang, Yu. J., Han, Z. H., Yang, S. and Wang, X., 2016. Anchoring Principles of a New Energy-Absorbing Expandable Rock Bolt, Engineering Transactions, 64(1), pp. 89–103.

6. Li, C. C., Stjern, G. and Myrvang, A., 2014. A review onthe performance of conventional and energy-absorbing rockbolts Journal of Rock Mechanics and Geotechnical Engineering, 6, pp. 315‒327.DOI: 10.1016/j.jrmge.2013.12.008.

7. He, M., Gong, W., Wang, J. Qi, P., Tao, Zh., Du, Sh. and Peng, Y., 2014. Development of a novel energy-absorbing bolt with extraordinarily large elongation and constant resistance. International Journal of Rock Mechanics and Mining Sciences, 67, pp. 29‒42. DOI: 10.1016/j.ijrmms.2014.01.007.

8. Liang, Y., He, M., Cao, C., Wang, S. and Ren, T., 2017. A mechanical model for conebolts, Computers &Geosciences, 83, pp. 142–151. DOI: 10.1016/j.compgeo.2016.10.017.

9. Sakhno, S. V., Isayenkov, O. O., Lyashok, Ya. O. and Sakhno, І. G., 2017. MPK(2006) C04B 7/00 Self-expanding non-explosive mixture. Ukraine.Pat. 119161,

10. Sakhno, I. G. and Molodetsky, A. V., 2013. Laboratory studies of the dynamics of growth of self-expansion pressure of non-explosive destructive mixture in typical deformation modes, Ground control in mining, 20‒21, pp. 3‒17.

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ISSN (print) 2071-2227,
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