A sensor assembly for a rock bolt, wherein the rock bolt includes a central rod, a split tube and a wedge anchor assembly fitted around the central rod, a rock plate, and a nut for attachment to an outer end of the central rod. The sensor assembly includes a distance sensor, a bracket for attaching the distance sensor to an outer portion of the split tube, an elongate spacing member configured to be fitted around the split tube between the nut and the rock plate to keep the nut and the rock plate spaced apart. The spacing member has an opening extending along at least a portion of the length thereof, the opening being sized large enough to allow movement of the bracket along a portion of the length of the spacing member with the distance sensor attached to the outer portion of the split tube by the bracket.

A setting device for a self-drilling anchor bolt of the present invention includes: a drive shaft, one end thereof having a shank for connecting to an impact tool, and another end being a setting part for pushing the self-drilling anchor bolt axially; a coupling, partially surrounding the drive shaft along an axis, and being supported on the drive shaft in such a way as to be incapable of relative rotation while being axially moveable at least locally; and a releasable locking component, disposed between the drive shaft and the coupling; in a locked position, the locking component is coupled to an extremity of an anchor rod such that the anchor rod is fed axially with rotational striking into a receiving material, and in a released position, the drive shaft strikes a sleeve to advance axially along the anchor rod and expand at an expansion part.

The present disclosure relates to a construction method for a deformable anchor cable capable of being prestressed. The anchor cable includes an outer sleeve, a shrinkage pipe, an inner sleeve, a steel strand, an anchor and a tray. When the anchor cable is in use, a hole is drilled first, then the anchor cable is mounted in the drilled hole, and finally a prestress is applied to the steel strand of the anchor cable. According to the construction method, the construction is convenient; the anchor cable has the characteristics of high strength and large deformation, and can be easily prestressed; and the large deformation is realized by squeezing the inner sleeve by means of the anchor, which completely overcomes the problem of breaking a cold-drawn rod during the large deformation process.

A friction rock bolt assembly is arranged to frictionally engage an internal surface of a bore formed in rock strata. The rock bolt includes an expander mechanism having at least two radially outer wedge elements engageable by an inner wedge element. The expander mechanism is configured for symmetrical displacement of the expander elements to provide controlled enlargement by the rock bolt within the borehole for secure anchorage.

The present disclosure is related to a multi-stage control negative Poisson self-expanding anchor apparatus. The apparatus is constructed to solve the problem of poor effect or even failure of anchor bolts owing to insufficient force area of the bolt and easy damage of the locking section under the action of large tension in the existing technology. The anchorage section mainly comprises a plurality of circular platform bodies spaced with larger outward and smaller inward along the axial direction. The axial inner segment of the round platform body is coaxial connected with the force resistant body, and the axial outer segment of the round platform body is opened with an axial inward through the hole of the force resistant body. The axial inner part of the force resistant body is fixed on the anchorage segment.

Disclosed is a method of adapting a metal bar, for use as a rock bolt, to ensure that the bar will break in a predictable manner, the method including the step of removing material from the bar in a circumferential band to reduce a diameter of the bar within the band to a minor diameter thereby to provide a failure zone within which the bar will break if subjected to enough tensile load.

A single-use sealing bush which is adapted to form a sealing interface between a rock bolt and a nozzle of a grout delivery system, the sealing bush including a cylindrical body defined between a first end and a second end; a hole in the first end of the body that is adapted to receive the rock bolt; a pair of spaced apart annular ridges, on an outer cylindrical surface of the body, between which a grout distributing channel is defined; and an aperture which connects the channel to the recess; wherein each annular ridge is adapted to seal against the nozzle in a position which communicates a grout inlet port of the nozzle with the grout distributing channel.

Disclosed is a rock bolt assembly including: a rock bolt with an elongate body which extends between a distal end and a proximal end and which has an integrally formed anchor portion and, where the body is not so formed, cylindrical stem portions; a tubular sleeve with a first diameter, which longitudinally extends between a first end and a second end, partially encasing the rock bolt so at least a proximal end portion of the bolt projects from the first end of the sleeve; a grout-input element which engages the rock bolt on the proximal end portion and which engages the first end of the sleeve in sealing contact; wherein, over each stem portion, the tubular sleeve is adapted along a band section by a reduction in the first diameter in a diametric plane; and wherein, over the anchor portion, the tubular sleeve retains the first diameter.

A drilling assembly is disclosed for drilling a borehole in a rock body and inserting a rock bolt within the borehole in a single pass. The drilling assembly includes an elongated drill string having a downhole end. A drill bit is detachably joined to the downhole end of the drill string, with the drill bit having an external screw thread extending in an axial direction of the drill string. The drill string is surrounded by a rock bolt sleeve that has a thread engaging formation at or near its downhole end and that is arranged to cooperate with the external screw thread of the drill bit so that the drill bit is able to be screwed into the rock bolt sleeve.

A friction stabilizer for supporting a rock ceiling in an underground mining environment is disclosed. The friction stabilizer has an external sheath and an internal rod. The internal rod is about 15% of the length of the external sheath. The internal rod has wedges at either end, arranged to engage with complementary wedges welded to the inside of the sheath.