Design and Testing
To achieve the designed ‘long life of a cable anchor it must be protected from the corrosive effects of the environment in which it is installed.
The anchor is comprised of high strength carbon steel wires which are twisted together to form a cable.
Australian Projects usually adopt BS 8081, Code of Practice for Ground Anchorages.
Primary cable protection is provided by a high density polyethylene sheath.
The sheath is corrugated where the cable is to be fully grouted so that the rock or ground load to be supported or reinforced, can be transferred to the steel cable anchor via the high density cement grout.
Cement grout is pumped up the inside of the corrugated sheath where it attaches to the cable anchor and the grout returns down the outside of the sheath and attaches to the drill hole wall.
The ground or rock load is thus transferred to the steel anchor via the cement grout and specially corrugated for the purpose sheathing. .
Where the anchor is to be decoupled from the drill hole wall to allow for ground movement, the anchor is installed in a smooth, high temperature grease filled polyethylene tube which is in turn cement grouted in a corrugated high density polyethylene tube grouted to the drill hole wall
Collar and toe fittings in contact with the ground or rock are manufactured from stainless steel . These are shown coloured green on the adjacent General Arrangement drawing.
Collar fittings include a bearing plate, articulation domed washer, tension lock nut and grout return outlet.