The invention relates to a yieldable rock anchor comprising an anchor element extending along a longitudinal center axis and having a first end, a second end and an outer surface. An anchor plate is attached near the first end of the anchor element, and an anchor head is secured to the first end of the anchor element and adapted to clampingly engage the anchor plate. On its outer surface, the anchor element is provided along at least substantially its entire length with a plurality of ribs. A plurality of sleeves, each sleeve having two opposing ends, for covering some of the plurality of ribs is fixedly arranged on the outer surface of the anchor element such that each of the opposing ends at least substantially sealingly engages the outer surface of the anchor element.

A friction bolt for frictionally engaging the internal surface of a bore includes a circular tube, which is split longitudinally, and which has a leading end and trailing end. An expander mechanism is disposed within the tube towards the leading end. An elongate bar/cable is disposed within the tube and extends between the expander mechanism at one end and an anchor arrangement at the other end. The bar/cable extends through a ring attached to the trailing end into connection with the anchor arrangement. A restrainer member is disposed within the tube adjacent the ring and extends at least partially about and in engagement with the bar/cable. The tube has a weakened region adjacent the ring and the restrainer member extends longitudinally within the tube past the weakened region. The restrainer member includes a projection that projects through the longitudinal split of the tube for engagement with the bore.

A rock bolt which includes a tubular member made from aluminium which is at a fixed position inside or outside a borehole, a cable which goes through the tubular member, and a steel barrel, secured to the cable which deforms the tubular member to give a yielding action with rock movement.

A prefabricated tunnel prestressed anchor comprises an anchor rod, the anchor rod comprises a free section and a prestressed section which are arranged in sequence; the prestressed section of the anchor rod is sleeved with a steel casing, holes are formed in the steel casing, a filler material is arranged between the steel casing and the anchor rod and filled in a space between the steel casing and the anchor rod after a prestress is applied to the anchor rod on a tensioning bench, and when the filler material is electrified, the structure of the filler material is destroyed; sleeves are arranged at two ends of the steel casing, and grout plugs used for sealing the steel casing are arranged in openings of the sleeves. The prestressed anchor can be directly installed in site to be used, a prestress is applied after the structure of the filler material is destroyed.

A rock bolt includes a tube having a leading end and a trailing end. An expander mechanism is disposed within the tube near the leading end. An elongate bar is disposed within the tube and is connected at a first end with the expander mechanism and at a second end with an anchor arrangement positioned at the trailing end of the tube. The elongate bar is arranged to actuate the expander mechanism and remain connected between the expander mechanism and the anchor arrangement while the expander mechanism is actuated. The tube has a displaceable wall section at the leading end, which has a hinge end proximal the leading end connecting the displaceable wall section to the tube. The expander mechanism can be actuated to displace the displaceable wall section to rotate about the hinge end to shift the anchor end outwardly from the tube.

A rock bolt includes a wedge-based expansion mechanism. The expansion mechanism includes a drive wedge arranged to expand an intermediate wedge upon tensioning of the rock bolt, wherein the intermediate wedge is arranged to expand a wedge device attached to an outer tube of the rock bolt. The use of the intermediate wedge enables greater expansion of the rock bolt.

A rock bolt includes a central rod, a tubular outer body provided around the central rod, and an expansion mechanism arranged for radially expanding the leading portion of the outer body. The rock bolt is arranged such that the outer body at installation is pulled into a bore of a formation from the leading portion of the outer body using a driving force applied via the central rod.

A driver socket for installation of a ground reinforcement bolt is provided. The driver socket includes a cylindrical tube having a longitudinal axis, wherein a leading end of the driver socket is configured to be arranged in connection to the bolt and a trailing end of the driver socket is configured to be arranged in connection to a driving device. The driver socket includes a through hole having. The through hole has a varying cross-sectional area along its axial length. The through hole has comprising a first diameter in a mid-section thereof that is smaller than a second diameter in a leading section thereof. The through hole has a transition located between the mid-section and the leading section. The transition has a frustoconical shape. An installation system including a ground reinforcement bolt and the driver socket is also provided.

A friction bolt (10) includes a first generally circular tube (12) having an internal diameter and defining a longitudinal split, the tube being radially expandable. The bolt has a first leading end (16) for insertion into a borehole (50), a second end defining a head (18), and a second generally circular tube defining a longitudinal split and having an external diameter which is substantially the same as or larger than the internal diameter of the first generally circular tube. The second tube is located inside the first tube (12) with an exterior of the second tube in contact with the interior of the first tube (12). The friction bolt (10) is installed in a rock face (80) using standard friction bolt (10) installation equipment and methods.

A rock bolt includes a tube having a leading end and a trailing end. An expander mechanism is disposed within the tube near the leading end. An elongate bar is disposed within the tube and is connected at a first end with the expander mechanism and at a second end with an anchor arrangement positioned at the trailing end of the tube. The elongate bar is arranged to actuate the expander mechanism and remain connected between the expander mechanism and the anchor arrangement while the expander mechanism is actuated. The tube has a displaceable wall section at the leading end, which has a hinge end proximal the leading end connecting the displaceable wall section to the tube. The expander mechanism can be actuated to displace the displaceable wall section to rotate about the hinge end to shift the anchor end outwardly from the tube.