UralEnergoResurs LLC, Magnitogorsk, Russia

S. S. Neugomonov, Technical Director, Candidate of Engineering Sciences
A. A. Zubkov, CEO, Doctor of Engineering Sciences

Nosov Magnitogorsk State Technical University, Magnitogorsk, Russia
I. M. Kutlubaev, Professor, Doctor of Engineering Sciences, ptmr74@mail.ru
V. A. Samigulin, Post-Graduate Student

Safety of mining is governed by the promptitude and quality of installation of mine support, and by the well-founded design of a support system, which conditions its load-bearing capacity. It is preferable to perform mine support system design using analytical models. This approach enjoys an active use in case of monolithic rock bolt supports reinforced with sand-and-cement and chemical mixtures. The applicability of the analytical models in these cases is stipulated by the certainty of the force interaction scheme in the rock bolt–reinforcement mixture–hole system. The article deals with the issues related to the method of calculating the load-bearing capacity of FRS anchors. The calculation is based on the determination of the friction force on the contact surface with the hole. To determine the force interaction, it is proposed to use an engineering approach based on the results of experimental studies. During their implementation, the composite models of boreholes were used. Based on the analysis of an anchor in the models of the hole, the scheme of its loading was determined. It is found that there is an enhanced interaction along the edges of the groove and the absence of contact on a significant part of the profile. An analytical model is developed, that makes it possible to calculate the load-bearing capacity of the anchor depending on its design parameters and steel grade. It is preferable to use anchors with a wall thickness of 2.5 mm and steel with a yield strength of more than 300 MPa. Experimental studies made it possible to assess the validity of using the finite elementbased modeling to assess the stress state of the anchor. A discrepancy between the generated displacements according to this model and the displacements recorded in the models of holes is found. This allows us to conclude that the assumptions made by the author of the numerical simulation A. A. Krechetov are wrong. The developed analytical method for determining the load-bearing capacity of rock bolts is experimentally approved and can be used in rock bolting design.

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