The use of steel and injection rock bolts to support mine workings when crossing tectonic faults

Abstract

Using the method of numerical modeling, the stability of mine working under difficult conditions of crossing a tectonic fault was studied as well as effectiveness of using steel rock bolts in combination with injection rock bolts. It was shown that steel and injection rock bolts complemented each other very well, increasing the stability of the mine working and reducing permeability of the host rocks. Injection rock bolts exclude the possibility of destruction of host rocks and more effectively reduce permeability of disturbed rocks in the zone of the tectonic fault. At the same time, steel rock bolts better restrain the expansion of the zone of high difference of the stress tensor components. Therefore, in case of heavily watered rocks or a high probability of methane breakthroughs into the mine working, it is better to install injection rock bolts as close to the mine face as possible. Then a water- and gas-proof shell arch around the mine working will be created in the immediate vicinity of the mine face. If there is no such threat and the priority is to maintain the long-term stability of the mine working, then first of all it is necessary to install steel bolts.