Groutable rock anchor assembly

A rock anchor assembly which includes a rock anchor comprising a flexible element and a first and a second cylindrical connector element engaged to a proximal end portion and a distal end portion respectively of the element;

• a tubular sleeve, made at least of a flexible material that longitudinally extends between a first end and a second end, on the rock anchor such that end parts of the rock anchor project from the first and second ends respectively of the sleeve;
• a load bearing barrel which is centrally bored to engage the first connector element between the first end of the sleeve and a proximal end of the rock anchor, which barrel is adapted to engage with the first end of the sleeve in sealing contact, and which barrel has at least one grout conduit between an exterior surface of the barrel and the bore, which at least one conduit defines a part of a grout passage which communicates the exterior surface of the barrel with an interior of the sleeve, when the barrel is sealingly engaged with the sleeve;
• a seal which seals the grout passage to grout outflow but accommodates inflow of grout from a source;
• a tensioning means engaged with the first cylindrical connector element between the proximal end of the rock anchor and the barrel;
• and a mechanical anchor engaged with the second cylindrical connector element;
• wherein the assembly includes a tubular spacer on the rock anchor between the first end of the sleeve and the forward end of the barrel or between the back end of the barrel and the tensioning means;
• wherein the tubular spacer is made of a suitable plastics material which deforms or breaks when a compressive force is applied to it to collapse or break away from the rock anchor, allowing the rock anchor to move longitudinally relatively to the sleeve between a first position and a second position;
• wherein the sleeve has a flared end section which opens onto the first end and an anchor housing section which opens onto the second end;
• wherein the mechanical anchor is at least partially received within the anchor housing section of the sleeve in an unexpanded configuration when the rock anchor is in the first position;
• wherein the mechanical anchor moves from the anchor housing section of the sleeve into an expanded configuration when the rock anchor is in the second position.