ROCK ANCHORS - STATE OF THE ART PART 2: CONSTRUCTION

Anchor construction techniques related to drilling, flushing, water testing, tendon preparation and installation, grouting and finally corrosion protection are discussed with emphasis on quality control and close on-site supervision. The drilling methods detailed include rotary drills and precussive drills. The choice of drilling method and drilling equipment are discussed. Drilling rates, flushing and alignment deviation are also reviewed. Water testing is described and recommendations are presented regarding waterproofing. The storage and handling of anchor tendons are discussed and recommendations are made regarding the avoidance of mechanical damage and corrosion. Comments are made with regard to the fabrication of anchors with multistrand or multiwire tendons, and the fixing and location of spacers and centralisers. Housing details are outlined.