An effectual method to control fracture of air return way in Niuxi mine

Based on the idea of integral structure reinforcement and superstructure-foundation-soil interaction in existing buildings, an effectual method with mini-pile grouting consolidation technology and reinforced concrete frame was applied to control and improve the structural stability of air return way of ventilation shaft in Niuxi Mine. The scheme is mainly consisted of three parts. The first, mini piles and high pressure double grouting was used to reinforce the foundation to improve its supporting capacity of filled ground. The second, reinforced concrete frame acting with brick masonry structure of air return way was adopted to improve their tensile strength and higher resistance to deformation. The last, settling tank and open ditch drainage was built to prevent the infiltration of surface water around the ventilation shaft.WT