Activation of threaded bolting elements

Abstract

The article deals with the activation of bolting elements with a thread on them or equipped with threaded bushing through drilling and installation device. The article also enumerates the most frequently used bolting elements of this type and applied equipment with technical parameters in the coal mines of the Ostrava-Karvina coal basin. The essence of the article is primarily to determine the actual height of the induced pre-tension in a bolting element, both in the laboratory and in real mining conditions and to compare these results with used mathematical formulae. The analysis of factors having effect on the level of the induced force and proposals for the limitation and reduction follows. The results show a good agreement of the calculated values with the values actually measured in various conditions. However, the results revealed that the induced input force is low, in the order of tens of kilonewtons. The main significance of the paper is to determine the value of the induced force, influencing factors and proposals to increase this value.

Keywords: Anchoring, bolting, drilling device, tensioning force