Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
  • E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
  • E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B5/00—Making ropes or cables from special materials or of particular form
  • D07B5/005—Making ropes or cables from special materials or of particular form characterised by their outer shape or surface properties
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
  • E02D5/74—Means for anchoring structural elements or bulkheads
  • E02D5/80—Ground anchors
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
  • E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
  • E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
  • E21D21/006—Anchoring-bolts made of cables or wires
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2201/00—Ropes or cables
  • D07B2201/20—Rope or cable components
  • D07B2201/2071—Spacers
  • D07B2201/2074—Spacers in radial direction
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
  • E02D5/74—Means for anchoring structural elements or bulkheads
  • E02D5/80—Ground anchors
  • E02D5/808—Ground anchors anchored by using exclusively a bonding material

Definitions

• the present invention relates to a cable bolt for use in the ground stabilisation.
• Cable bolts are used in a number of different applications in the mining and civil industries, such as for underground stoping, pillar support, development support and in open pit and civil applications where slope stabilisation is required.
• cable bolts are used by drilling holes through potentially unstable ground into more solid strata into which the cable bolts are located securely by grouting.
• cable bolts are located to extend through the ore body to be mined and are at least partially exposed as the ore body around the cable bolts is removed by blasting. In other situations, cable bolts are located to extend through potentially unstable material which is not part of the ore body to be mined and, by stabilising the material, the cable bolts prevent such material mixing with the ore body to be mined and thereby increasing the volume to be processed and accordingly the costs of winning the valuable minerals.
• a basic form of conventional hitherto widely- used cable bolt (hereinafter referred to as the "basic form of cable bolt") comprises a central wire and a plurality of outer wires (typically 6 or more) wound around the central wire in parallel spirals.
• the wires are usually formed from high tensile strength steel, and usually the cable bolt is stress relieved after it is formed.
• the foregoing basic form of cable bolt has been found to have relatively low load transfer with the result that over time the mechanical interlock between cable bolt and grout is substantially reduced.
• this has not proven to be altogether successful in terms of performance and also is a relatively expensive technique.
• a further known approach to improve the load transfer capability is to modify the configuration of the basic form of cable bolt.
• the modified form known as a "birdcage" comprises a plurality of enlarged diameter regions along the length of the cable bolt formed by selectively unwinding the cable bolt at the regions so that the wires can separate and bulge outwardly.
• An object of the present invention is to provide a cable bolt which alleviates the disadvantages described in the preceding paragraphs.
• a cable bolt comprising, a central wire, a plurality of core members positioned at spaced intervals along the length of the central wire, and a plurality of outer wires wound around the central wire and the spaced apart core members so that the width of the cable bolt is greater at the locations of the core members than at the sections between the core members.
• core member is understood herein to include any member that increases the effective width of the central wire and, as a consequence, the effective width of the cable bolt at the location of the core member.
• the central wire and the outer wire be formed from steel.
• the core member comprises a relatively wide middle section and relatively narrow ends and a central passage extending from end to end for receiving the central wire therethrough. It is preferred particularly that the core member tapers from the middle section to each end.
• the core member be formed from a plurality of longitudinal sections which fit together around the central wire. It is preferred that the core member be formed from substantially incompressible material.
• the core member increase the diameter of the central wire by at least 20%.
• a method of forming a cable bolt comprising, winding a plurality of outer wires around a central wire having a plurality of core members fitted to the central wire at spaced intervals along the length thereof. It is preferred that the method further comprises coiling the cable bolt onto a spool.
• a method of forming a cable bolt from a basic form of cable bolt comprising a central wire and a plurality of outer wires around the central wire, the method comprising radially displacing the outer wires from the central wire to form a space between the central wire and the outer wires, and fitting a core member to the central wire in the space. It is preferred that the method further comprises repeating the radial displacement and core member placement steps to fit a plurality of the core members along the length of the central wire.
• the method further comprises coiling the cable bolt onto a spool.
• the present invention is described further with reference to the accompanying drawing which is a side elevation of a part of a preferred embodiment of a cable bolt of the present invention.
• the preferred embodiment of the cable bolt 3 of the present invention shown in the drawing comprises a central steel wire 5, a plurality of core members 7 (only one of which is shown in the drawing) at spaced intervals along the length of the central wire 5, and a plurality of outer steel wires 9 wound around the central wire 5 and the spaced apart core members 7.
• Each core member 7 is formed from substantially incompressible material such as steel and comprises a relatively wide middle section 11 and relatively narrow ends 13 with a central passage 15 extending between the ends 13.
• Each core member 7 tapers from the middle section 11 to the ends 13 and is formed in 2 halves which (although not evident in the drawing) can conveniently be located together around the central wire 5.
• the core members 7 cause the cable bolt 3 to have a variable thickness along the length thereof with a maximum thickness which is at least 20% greater than the minimum thickness T 1 of the cable bolt 3.
• the effect of the core members 7 and the windings of the outer wires 9 around the core members 7 is that the cable bolt 3 has a similar load transfer capability to that of swaged cable bolts.
• the cable bolt 3 is manufactured with conventional technology used to form the basic form of cable bolt and thereafter coiled onto spools which can conveniently be stored and transported on-site.
• the preferred embodiment comprises:
• the cable bolt 3 is manufactured from the basic form of the cable bolt and thereafter coiled onto spools which can conveniently be stored and transported on-site.
• the preferred embodiment of the method comprises, repeatedly:
• the cable bolt 3 has the following characteristics.
• the stiffness of the cable bolt 3 can be varied by decoupling the cable bolt 3 from the grout along the length of the cable bolt between adjacent core members 7 or by varying the transverse thickness of the core members.
• the core members 7 have a particular configuration
• the present invention is not so limited and extends to any suitable configuration which has the effect of increasing the effective diameter of the central wire 5 and thereby the effective diameter of the cable bolt.
• one alternative configuration of core members 7 comprises lengths of wire wrapped around the central wire 5 at spaced intervals along the length of the central wire 5.

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• Engineering & Computer Science (AREA)
• Structural Engineering (AREA)
• Mining & Mineral Resources (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Geology (AREA)
• Paleontology (AREA)
• Civil Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Bridges Or Land Bridges (AREA)

Applications Claiming Priority (3)

Publications (2)

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Family Applications (1)

Country Status (3)

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Citations (2)

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• 1993
  • 1993-02-02 EP EP93903108A patent/EP0628114A4/fr not_active Withdrawn
  • 1993-02-02 CA CA002129220A patent/CA2129220A1/fr not_active Abandoned
  • 1993-02-02 WO PCT/AU1993/000044 patent/WO1993015279A1/fr not_active Application Discontinuation

Patent Citations (2)

Non-Patent Citations (1)

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