Mine shaft, as the important channel of underground mining, plays a decisive role in mining work. Due to mining, the shaft deformation in Jinchuan No.2 mining area caused huge economic loss. After repeated experimental verification, the construction team and engineers decided to use R38 self drilling anchor bolt to repair and reinforce the shaft.
The reason why self drilling rock bolt is chosen is that it has the following advantages:
1) Self drilling anchor bolt can combine drilling, grouting and anchoring simultaneously, which greatly improves the construction efficiency;
2) It can be fully grouted and achieve pressure grouting, which improves the project quality;
3) Due to the interaction of the accessories, the hollow bar is in the middle position, which ensures uniform grouting. And the cement sully can cover full length of the anchor bolt to avoid the possibility of corrosion and achieve long-term support;
4) It can be used with standard hand-held rock drills without using large drilling rig.
In repair process, cement slurry is injected into the loose rock cracks around collapsed shaft through hollow anchor bar, which further improves stability of the loose rock around collapsed shaft. This is fully utilized anchoring effect of self-drilling anchor bolt and effectively controls the deformation of loose rock in the shaft. Especially after the cement slurry is solidified, shallow fractured rock forms a whole. The overall self-stability of slope rock mass can be effectively improved by anchoring a large range of rock with staggered arrangement of long and short bolts.
The successful application of self-drilling anchor bolt in mine shaft repairment provides reference for mining and support engineering of mine shaft. At the same time, deep mining is the major factor that causes regional rock movement and deformation, which has significant influence on mining area and mine shaft. It is also a research direction worthy breaking through in the future to continue to explore the methods of early reinforcement and late repair of mine shaft.