Rock anchors also known as rock bolts provide structural solutions for unstable rock slopes. Rockbolts can be installed using hand-held or rig-mounted equipment and are often used to provide the anchor points from which mesh is fixed.
For longer bolts, couplers are used to join bars together to reach the required length. In environments where corrosion is likely or up to a 120 years design life is required, a range of materials including stainless steel bar and GRP is used.
For fixing, a wide range of options is available, from a cementitious based grout through to specialist resins and mechanical fixings. With our own qualified geotechnical engineers, Condor Projects can offer the full solution to bolting, from design to installation and testing to BS8081.
Often, a rock bolt will be made up from hollow drill steels and sacrificial drilling bits. During drilling, grout is pumped through the centre of the drill steel and flushes any debris from the hole. Once at its required length, the drill string is cut and becomes the anchor. This is particularly ideal for poor ground conditions where ‘open-hole’ drilling is unlikely to succeed.
Other solutions also available from Condor Projects include the use of spade or sock anchors. Spade anchors, usually in the form of either Platipus or Duckbill Earth Anchors, consist of an anchor head attached to a flexible steel tendon or bar. The anchor head is driven into the ground to the required depth and the tendon stressed, causing the anchor head to rotate through 90° and ‘load lock’.
Sock anchors consist of a solid or hollow steel bar inside a fabric sock and are used in areas where the rock is heavily fissured. As the grout is pumped into the ‘sock’, the sock deforms to the shape of the fissure.