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 friction bolt assembly to frictionally engage a bore formed in rock strata includes an elongate tube and an expander mechanism acted on by an anchor mechanism via an elongate bar or cable. A retainer mechanism is mounted to act between the bar or cable and the tube to prevent ejection of the bar or cable from the assembly should the bar or cable break.

A friction bolt assembly has a tubular friction bolt body defining a cavity and having a split. A rod extends through the cavity. An expansion element is mounted on the rod at or toward the rod leading end and protrudes through the friction bolt body leading end. The expansion element has an engagement surface tapering toward the rod trailing end. A drive head is mounted on the rod at or adjacent the rod trailing end. The rod is actuatable by rotation of the drive head to draw the expansion element toward the friction bolt body trailing end such that the engagement surface engages the friction bolt body, radially outwardly deforming the friction bolt body.

Friction stabilizer pull tester apparatus and method for testing friction stabilizer type rock bolts including a pull tester toolhead comprising a tension rod with a radially expanding collet device inserted and expanded in a friction stabilizer steel tube. A confining collar on the tension rod for restricting longitudinal movement of the expanding device and outward deformation of the friction stabilizer tube at a friction stabilizer ring flange. A pre-tensioning device applies an initial force to seat apparatus and a pulling apparatus applies a greater load force to the tension rod to determine load capacity of the friction stabilizer.

This invention puts forward a sectional modular large-deformation-resistant impact-resistant composite rock bolt and its assembling method. The outer anchor module of this composite rock bolt consists of the outer anchor end, anchor tubes and anchor piers, all of which are bonded with the borehole wall through the anchorage agent to act as a full-grouted bolt. And the inner anchor module consists of the outer anchor end, anchor piers, springs and threaded rod. The threaded rod, under the traction by the outer anchor end, presses the inner anchor springs to distribute the anchoring force to the anchor piers, which then pass such force as a pressure to the anchoring agent, thus playing the role of a pressure-dispersive anchor. Before the failure of the anchor tube, the inner anchor module is in parallel with the outer anchor module, playing the role of auxiliary anchorage on surrounding rock; after the failure of the anchor tube, such structure can yield and buffer effectively against the surrounding rock and realize secondary high-strength support timely.

A bolt or anchor 10 typically used in a rock body 14. The anchor 10 comprises an internal gripping formation with which the anchor can be fixed relative to the rock body 14. Moreover, the anchor 10 comprises an elongate body 20 which is configured for, in use, being received at least partially within a hole 12 in the rock body 14. The anchor 10 also comprises an internal fixing arrangement 30 which comprises a substance 32 which is received within a containing arrangement 34. In use, the containing arrangement 34 is arranged within the hole 12. An activating arrangement 36 is provided and configured for, in use, actuating the containing arrangement 34 and causing the internal fixing arrangement 30 to engage with the hole, thereby causing the elongate body 14 to become fixed within the hole 12.

An inflatable rock bolt including an expansion tube, a bushing arranged at each end of the expansion tube, and at least one reinforcing member arranged outside the expansion tube. The at least one reinforcing member includes at least one of a strand extending along the expansion tube or a sleeve at least partially surrounding the expansion tube. A method for reinforcing an inflatable rock bolt.

A rock bolt includes an elongate metallic body having a first end and an opposed second end, a threaded portion at the second end, for attaching thereto and locating thereon, a nut and a bearing plate, a mechanical anchor at, or at least partially located on, a first end portion of the body and a first resistive anchor, located between the threaded portion and the mechanical anchor.

Rock bolts comprising an expandable tube having a longitudinally extending depression disposed between two curved outer portions of the tube, wherein the depression defines a channel having an opening defined between the two curved outer portions of the tube and the width of the opening is at least 10% of the width of the tube and/or a coating layer covers at least a portion of the expandable tube. Also, a method of manufacturing a rock bolt comprising forming an expandable tube comprising a longitudinally extending depression disposed between two curved outer portions of the tube, crimping a proximal end of the tube to form a crimped portion, and placing a sleeve around the crimped portion. Prior to crimping, a temporary spacer is placed in the channel in a portion of the tube adjacent to the portion of the tube that will be crimped.

A drilling assembly for simultaneously drilling a hole and inserting a friction bolt, the drilling assembly comprising a drill string, a drill bit and a friction bolt, wherein: (i) the drill string defines a leading end adapted to releasably operatively connect to the drill bit and a trailing end adapted to operatively engage with a means for imparting energy on said drill string; (ii) the drill bit is mounted on the leading end of said drill string; (iii) the friction bolt at least partially surrounds said drill string; and wherein (iv) the drilling assembly further comprises an elongate spacer that defines a leading end and a trailing end and is located between said friction bolt and said means for imparting energy on said drill string.