Method of placing rockbolt via medium=filled cavity and drillrod

摘要

An elastically deformable plug (16) of rubber or plastics to displace the medium already inserted in the drilled borehole (1) is driven into the drillrod (5) so as to close off the outlet (11,13,14) and allow the cavity (4) to be used as normal for rockbolt setting. The plug should be driven hydraulically into the rod and the fluid or settable medium is used to locate a tie within the drillrod. Otherwise the tie is run into the rod after plugging. The medium may be preferably synthetic resin or cement suspension and the flushing medium may also be a cement suspension. The tie should be solid rod or steel wire rope and cased in plastics over a defined rod length. When paper or cellula swellable material is used for the plug, this material necessarily swells out and may present a spherical or ellipsoidal form whose diameter can fit snugly to the inside diameter of the drillrod.