ABSTRACT
Soil and rock anchors have found a range of temporary and permanent applications in the building industry and in the mining and civil engineering fields. The Silurian rock has been extensively folded and many joints exist in the rock structure. Drilling by air flushing techniques is possible in all weathered rock conditions and it has also proved to be the best technique for drilling the Silurian clays and Tertiary sandy clay/clayey sands above the water table due to their relatively low moisture content. Where anchors are to be placed into rock, all anchor holes should be tested for watertightness before installation of the anchor, since subsequent loss of grout from around the tendon in the anchorage zone is critical in relation to efficient load transfer and corrosion protection. The cheapest and most common material used to bond anchors into the soil or rock is cement grout.
