BOLT ANCHORAGE FOR SHALLOWLY-BURIED,WIDE-SPAN, AIR-DEFENCE CHAMBER SURROUNDED BY POOR ROCK

The requirement on safety of underground air-defence chamber is very high,especially when the chamber is shallowly buried,of wide span and surrounded by poor rock.Of similar conditions is the Longshan underground store in Oingdao city which can be used as air-defence shelter in war.To ensure a safe construction and provide a high quality chamber with long service-life,technique of such as long cable anchor,short bolt,steel wire mesh,steel fibre shotcrete,steel arch frame has been successfully adopted for strengthening the wall rock.