A rock bolt assembly provides an indication of a coupling. The rock bolt assembly includes two shaft sections, namely inner and outer shaft sections. A coupler is configured to couple the two shaft sections together at proximate ends. An electrical conductor is insulated from the outer shaft section and extends from the dead end of the outer shaft section to the head at the live end of the outer shaft section. An electrical contact arrangement is provided at the dead end of the outer shaft section, configured to electrically interconnect the outer shaft section and the conductor when the inner and outer shaft sections are coupled. Electrical terminals are provided at the head and connected respectively to the outer shaft section and to the conductor, the electrical terminals being electrically interconnected or continuous when the outer shaft section and the conductor are electrically interconnected.

A rock bolt assembly provides an indication of a coupling. The rock bolt assembly includes two shaft sections, namely inner and outer shaft sections. A coupler is configured to couple the two shaft sections together at proximate ends. An electrical conductor is insulated from the outer shaft section and extends from the dead end of the outer shaft section to the head at the live end of the outer shaft section. An electrical contact arrangement is provided at the dead end of the outer shaft section, configured to electrically interconnect the outer shaft section and the conductor when the inner and outer shaft sections are coupled. Electrical terminals are provided at the head and connected respectively to the outer shaft section and to the conductor, the electrical terminals being electrically interconnected or continuous when the outer shaft section and the conductor are electrically interconnected.

A rock anchor assembly includes a rock anchor with a flexible element and first/second cylindrical connector elements engaged to proximal and distal ends of the element, a flexible tubular sleeve longitudinally extending between first and second ends, on the rock anchor so end parts of the rock anchor project from sleeve ends; a load bearing barrel centrally bored engaging the first connector element between the first end of the sleeve and a proximal end of the rock anchor, the barrel engaging the first end of the sleeve in sealing contact, the barrel having a grout conduit between the barrel exterior and the bore, the conduit defining part of a grout passage interconnecting the barrel exterior and sleeve interior, when the barrel engages the sleeve; a seal preventing grout outflow but accommodating grout inflow; a tensioner engaging the first tubular connector element, and a mechanical anchor engaging the second tubular connector.

A friction bolt assembly to frictionally engage a bore formed in rock strata. The assembly 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.

An active control method and device for large deformation of a deep thin-bedded surrounding rock, the active control method includes: drill holes in the surrounding rock of a tunnel against a tunnel face, add the active control device containing a sleeve, a high-strength prestressed anchor bolt, a resin anchoring agent and a grouting device into drill holes, apply a preload to the anchor bolt when the resin anchoring agent has a certain strength, and carry out lag grouting in the surrounding rock through the grouting device after stress adjustment, and the high-strength prestressed anchor bolt and the grouting device are inserted in the sleeve with holes on the side. The active control device or method of the invention can effectively reduce the fracture depth and degree of a thin-bedded soft rock in deep engineering, and effectively inhibit the occurrence of large deformation disasters.

A system for re-tensioning mine roof channels includes a roof plate having a first side, a second side positioned opposite the first side, and a sidewall extending therebetween, where the first side is configured to engage a surface of a mine roof, and where the sidewall defines a radially extending slot configured to receive a mine roof bolt. The system also includes a spacer having a first side, a second side positioned opposite the first side, and a sidewall extending therebetween, with the first side of the spacer configured to engage with the second side of the roof plate, and the sidewall defining a slot configured to receive a mine roof bolt, and a nut having a first side, a second side positioned opposite the first side, a sidewall therebetween, and a threaded opening, with the sidewall defining a radially extending slot configured to receive a mine roof bolt.

Disclosed is a rock bolt assembly for installing a mesh panel against a rock face which includes a rock bolt which has an elongate body extending between a first end and a second end, a cylindrical bush engaged with the bolt body, towards the second end, the cylindrical bush having a plurality of annular or arcuate grooves formed in an exterior of the surface of the bush and a washer having a plate-like body with an aperture formed there through.

A high-strength confined concrete support system for an underground tunnel. The support system includes multiple confined concrete arches, bolts and cables, and a prestressed steel strand backfilling system. The confined concrete arches all support the surrounding rock of the tunnel and are sequentially arranged along the tunnel. Every two adjacent confined concrete arches are connected by a longitudinal connection structure. The support system is provided with a plurality of layers of steel bar meshes on the surrounding rock side and the tunnel side, and shotcrete layers are sprayed on the support system and the steel bar meshes. The prestressed steel strand backfilling system comprises a prestressed steel strand system and a filling material. The filling material fills the space between each confined concrete arch and the surrounding rock to equalize a load on the confined concrete arch and generate prestress.

A rock bolt (10) is provided for frictionally engaging with the internal surface of a bore drilled into rockmass. The bolt comprises a tube having a circular cross-section (12) defining a longitudinal split (14) and a longitudinal axis (10a). The tube (12) in is radially expandable. The bolt (10) has a first leading end (12b) for insertion into a bore, a second end defining a head (12a) and expander means (30) for expanding the diameter of the tube at least one location along the tube. The expander means comprises first (42) and second (44) expander/wedge elements arranged so that relative movement of the two elements causes the diameter of the tube to expand at that location. The first expander element (42) is mounted on an elongate rod (30) which is aligned generally along the longitudinal axis of the tube. Rotation of the rod (30) causes the relative movement of the two elements to cause the diameter of the tube to expand at the location. The rock bolt includes an arrestor (100) in the form of a ring, which defines an aperture which locates on the proximal end of the rod (30). The aperture is larger than the proximal end of the rod so that the arrestor is able to move along the proximal end of the rod. The arrestor includes a laterally extending protrusion (102) which locates in the longitudinal split (14) and is narrower than the longitudinal split and which is configured to engage with the head of the friction bolt when moved towards the proximal end of the friction bolt.

A rock bolt (10) is provided for frictionally engaging with the internal surface of a bore drilled into rockmass. The bolt comprises a tube having a circular cross-section (12) defining a longitudinal split (14) and a longitudinal axis (10a). The tube (12) in is radially expandable. The bolt (10) has a first leading end (12b) for insertion into a bore, a second end defining a head (12a) and expander means (30) for expanding the diameter of the tube at least one location along the tube. The expander means comprises first (42) and second (44) expander/wedge elements arranged so that relative movement of the two elements causes the diameter of the tube to expand at that location. The first expander element (42) is mounted on an elongate rod (30) which is aligned generally along the longitudinal axis of the tube. Rotation of the rod (30) causes the relative movement of the two elements to cause the diameter of the tube to expand at the location. The rock bolt includes an arrestor (100) in the form of a ring, which defines an aperture which locates on the proximal end of the rod (30). The aperture is larger than the proximal end of the rod so that the arrestor is able to move along the proximal end of the rod. The arrestor includes a laterally extending protrusion (102) which locates in the longitudinal split (14) and is narrower than the longitudinal split and which is configured to engage with the head of the friction bolt when moved towards the proximal end of the friction bolt.