DEVELOPMENT AND APPLICATION OF THE BEARING-BOLT SUPPORTING TECHNOLOGY IN THE CONDITIONS OF UKRAINIAN COAL MINES

Abstract

Purpose. To substantiate the parameters of formation of elements in the roof-bolting construction and to establish the dependence of displacements of the mine working contour on the technological parameters of mine working driving and supporting for development of the bearing-bolt supporting technology in the conditions of Ukrainian coal mines. Research methods. To study the process of changing the stress state of host rocks around the mine working during the technological cycle of setting of roof bolts, a mathematical elastoplastic model was developed. This model takes into account roof bolts parameters, mining parameters, rock properties, as well as the time and place of the start of roof bolting. The problem was solved using the finite element method. The methods of researching the state of the rock around the mine working with roof bolts, which were developed by the authors, were used during the calculations. Results. The mechanism of formation of a rock-bolt support and a reinforced arch in the mine roof was studied. The conditions and parameters of formation of the following elements in the roof-bolting construction are substantiated: load-bearing and backing-up parts of the arch, supports of the arch, a base of the structure and protective “bridges”. Numerical simulation of the stress-strain state of the host rocks was completed when various elements of the roof-bolting construction were used. Graphs of the relative heaving of the mine work floor were constructed. In order to study the influence of the speed of the mine working advance and the distance between the first row of bolts and the mine working face on the mine working stability, simulations were performed for various technological schemes. The dependence of changes in roof displacements on these technological parameters was obtained: decreasing the distance between the first row of bolts and the mine face and increasing the speed of the mine working advance lead to a decrease in rock displacements and an increase in the stability of the mine working. Scientific novelty. A new method of calculating the parameters of the stress state of the host rock and the roof-bolting construction during the technological cycles of bolts setting was developed. This method takes into account that during each cycle the host rock is unloading from the rock pressure and that the bolts start to work at a certain point in time. Methods of erecting roof-bolting constructions using various elements were developed and confirmed by patents. Practical significance. The use of roof-bolting constructions in 52 mines of Ukraine made it possible to achieve a stable state of mine workings in difficult mining and geological conditions and to obtain a great economic effect due to the reduction of costs for operation and repair of mine workings.