The combined strengthen technology of bolt-shotcreting-grouting for loose and fractured surrounding rock

In order to solve the problem of serious deformation of dip track roadway in mining area No.9 and combined with the actual situation,the deformation reasons of this roadway were many fault structures,low rock intensity and poor construction quality.Based on the analysis,there existed partition in the radial direction of bolting and shotcrete roadway,which was the anchor spray layer,the granular layer and the deep fracture layer in turn.the loose and fractured surrounding rock in the granular layer and the fully developed fractures in the deep fracture layer were the main factors leading to instability in the later period of the roadway.By consolidating the rock and filling the cracks,grouting provided a stable foundation for the bolt (cable).Besides,the loose broken rock and anchor bolt (cable) were cemented as a whole by grouting,and a composite bearing structure was formed which improved the stability of the roadway.Field application has shown that the dip track roadway was basically stable 40 days after maintenance and reinforcement.The deformation of both sides and roof to floor were 67mm and 45mm respectively,meeting the needs of production.