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WO2008000015A1 - Boulon d'ancrage auto-foreur - Google Patents

Boulon d'ancrage auto-foreur Download PDF

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Publication number
WO2008000015A1
WO2008000015A1 PCT/AU2006/001670 AU2006001670W WO2008000015A1 WO 2008000015 A1 WO2008000015 A1 WO 2008000015A1 AU 2006001670 W AU2006001670 W AU 2006001670W WO 2008000015 A1 WO2008000015 A1 WO 2008000015A1
Authority
WO
WIPO (PCT)
Prior art keywords
shaft
rock bolt
self drilling
drilling rock
bolt according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/AU2006/001670
Other languages
English (en)
Inventor
Steven Weaver
Darren Webb
John Horsch
Matthew Kenny
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sandvik Intellectual Property AB
Original Assignee
Sandvik Intellectual Property AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sandvik Intellectual Property AB filed Critical Sandvik Intellectual Property AB
Publication of WO2008000015A1 publication Critical patent/WO2008000015A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • E02D5/801—Ground anchors driven by screwing
    • 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
    • E21D21/0053—Anchoring-bolts in the form of lost drilling rods
    • 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
    • E21D21/008—Anchoring or tensioning means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B13/00—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
    • F16B13/002—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose self-cutting
    • F16B13/003—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose self-cutting with a separate drilling bit attached to or surrounded by the dowel element
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B13/00—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
    • F16B13/002—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose self-cutting
    • F16B13/004—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose self-cutting with a drilling sleeve driven against a tapered or spherical plug

Definitions

  • the present invention relates to rock bolts suitable for use in the mining and tunnelling industry to provide roof and wall support.
  • the invention is suitable for use in hard rock applications as well as in softer strata, such as that often found in coal mines, and it is to be appreciated that the term "rock" as used in the specification is to be given a broad meaning to cover both these applications.
  • Roof and wall support is vital in mining and tunnelling operations.
  • Mine and tunnel walls and roofs consist of rock strata, which must be reinforced to prevent the possibility of collapse.
  • Rock bolts are widely used for consolidating the rock strata.
  • a hole is drilled into the rock by a drill rod, which is then removed and a rock bolt is then installed in the drilled hole and secured in place typically using a resin or cement based grout .
  • a self drilling rock bolt that comprises first and second ends, a shaft extending between the ends, an anchoring device, and a sleeve extending along and around the shaft, the first end having a drill tip to penetrate rock and the second end being adapted to be connected to a drilling apparatus to allow rotation of, and thrust to, the bolt, a passage being formed between the sleeve and the shaft to allow fluid to be passed along the shaft, and the anchoring device being operative to retain the bolt when located in a drilled hole and comprising a mandrel having one or more external surfaces that are inclined to the shaft, the mandrel being mounted to or integrally formed with the shaft and at least one expansion element overlaying the mandrel, wherein the at least one expansion element is displaced radially outwardly on a predetermined relative movement between the mandrel and the at least one expansion element .
  • the anchoring device extends along a first part of the shaft adjacent the first end, and the sleeve is disposed adjacent the anchoring device and extends along a second part of the shaft towards the second end.
  • a collar is disposed on the shaft to seal the end of the sleeve adjacent the anchoring device .
  • the bolt shaft includes an inner passage that opens to the passage formed between the sleeve and the shaft, the inner passage being arranged to convey fluid along at least a part of the length of the shaft .
  • the inner shaft is arranged to convey fluid along the first part of the shaft.
  • the bolt further comprises a sealing element that is disposed adjacent the second end and which is arranged to seal the end of the sleeve to the shaft .
  • the sealing element includes a port to allow fluid to be introduced or extracted from the passage.
  • the bolt is rotatable about its axis in a first direction in a drilling operation and is rotated in an opposite second direction to cause the predetermined movement between the mandrel and the at least one expansion element so as to enable the anchoring device to become operative to retain the bolt in a drilled hole .
  • the surface (s) is generally flat so as to give the mandrel a wedge-shaped profile. In another form, the surface (s) is curved.
  • the mandrel is mounted to the shaft.
  • the at least one expansion element and the mandrel may be connected to the bolt shaft in a manner that allows them to be rotatable relative to the shaft about the bolt axis.
  • the inner surface of the at least one expansion element and the external inclined surface (s) are shaped so that relative rotation between the at least one expansion element and the mandrel is prevented. As such, the at least one expansion element and the mandrel rotate together about the bolt shaft .
  • the at least one expansion element is restrained from axial movement along the bolt shaft, whereas the mandrel is movable axially along the shaft in a direction that causes outward displacement of the at least one expansion element. Accordingly, with this configuration, rotation of the shaft relative to the anchoring device induces relative movement between the at least one expansion element and the mandrel to cause the radial outward displacement of the at least one expansion element.
  • the mandrel is connected to the shaft via a threaded coupling comprising an external thread on the shaft and a complementary inner thread disposed on an inner surface of the mandrel.
  • the threaded coupling induces axial movement of the mandrel on the shaft under relative rotation between the shaft and the mandrel .
  • movement of the mandrel down the shaft i.e. towards the second end
  • the anchoring device further comprises a band disposed about the at least one expansion element.
  • the band has two primary functions; a first function is to retain the expansion element in a retracted condition, a second function is to promote relative rotation between the anchoring device and the bolt shaft when the bolt is rotated in the second direction so as to instigate the radial outward displacement of the expansion element.
  • the band includes a profiled surface that is arranged to pass over the rock surface of a drilled hole on rotation of the bolt in the first
  • the band incorporates a band body and a plurality of flaps which form the profiled surface of the band and which extend from the band body.
  • the flaps are biased to fold against the band body when rotated in the first direction and are biased to extend outwardly so as to grip the wall surface of the drilled hole when the bolt is rotated in the second direction.
  • the band is formed from a polymeric material.
  • the shaft is typically made from steel and the passage formed by the sleeve provides part of a circulation passage to allow drilling fluid to be introduced, or withdrawn, at the second end of the bolt and to enable grout to be pumped into the drilled hole to set the rock bolt in place.
  • the circulation passage further includes a second passage that is formed between the bolt shaft and the wall surface of the drilled hole.
  • a primary purpose of the sleeve is to provide the passage for circulation of fluid.
  • the sleeve is made from a material that is able to collapse under load (to allow tensioning of the bolt as will be discussed in more detail later) . Whilst the sleeve may be made from a wide range of materials, in one form, it is made from plastic.
  • the drill tip has an outer edge that is displaced radially outwardly from the bolt axis a distance greater than the sleeve to provide the passage between the bolt and the wall of the drilled hole.
  • the drill tip is located directly on the shaft of the bolt, which may be modified to accept the drill tip such as through a milling or forging operation.
  • the rock bolt further comprises a drill bit which is connected to an end of the shaft and which incorporates the drill tip thereon.
  • the drill bit is connected to the end of the shaft by a coupling that is able to impart rotation to the drill bit from the shaft when the shaft is rotated in at least one direction.
  • the coupling may ⁇ be permanent i.e. the drill bit may be welded on to the shaft, or alternatively the drill bit may be removable.
  • the coupling may be in the form of interfitting projections and recesses that allow rotation to be imparted or alternatively a threaded coupling may be used wherein the drill bit incorporates a shank having an external thread and a complementary inner thread is disposed on an inner surface of the shaft.
  • the anchoring device is disposed adjacent the first end.
  • this expansion element may be restrained at one end of the at least one expansion element thereby allowing the remainder of the expansion element to extend radially outwardly.
  • the at least one expansion element may be seated in a groove disposed about the shaft or may be captured by a retaining collar disposed about the shaft.
  • the expansion element may be designed to be captured between the drill bit and the shaft end so as to restrain the expansion element from axial movement .
  • the expansion element projects proximally from its restrained end towards the second end of the rock bolt. In another form, the expansion element projects distally towards the first end of the rock bolt. In this latter arrangement, the at least one expansion element may be located in a groove, or bear against a retaining collar disposed on the shaft at a location spaced from the first end.
  • a plurality of expansion elements are provided which in use are angularly spaced about the shaft axis.
  • a connector is provided which interconnects the expansion elements and which is arranged to engage with the bolt shaft so as to prevent the axial movement of the expansion elements along the shaft.
  • this connector may be formed in multiple pieces, or able to be deformed, so as to extend about and locate in a recess in the shaft .
  • the expansion elements are formed as a single piece which incorporates a central aperture.
  • the expansion elements are designed to locate between the drill bit and the shaft end with a shank of the drill bit being arranged to extend within the aperture formed in the connector.
  • the shaft extends through the aperture and the expansion elements are held in place by one or more retaining collars.
  • the rock bolt further comprises a drive coupler disposed adjacent to the second end and which is designed to interengage with the drilling apparatus.
  • the drive coupler is also connected to the shaft so as to allow rotation and thrust to be imparted to the bolt shaft.
  • the drive coupler is in the form of a drive nut which is connected to the bolt shaft through a threaded coupling comprising an external thread disposed on the shaft and a complementary inner thread disposed on an inner surface of the drive nut .
  • the sealing element is located adjacent the drive nut and is constrained from axial movement towards the second end by the nut .
  • the sealing element and the drive nut are integrated into a single unit.
  • the drive nut therefore has the multiple functions of sealing an end of the sleeve to the shaft, providing a port to the passage formed between the sleeve and the shaft, and to be the coupling to the drilling apparatus.
  • the drive nut may be referred to as an "irrigated" drive nut.
  • a stop is provided which is operative to inhibit axial movement of the drive nut on the shaft.
  • this stop is in the form of a lock nut which is secured to the shaft and which is coupled to the shaft through a threaded coupling which preferably has a handed thread which is opposite to that used on the drive nut.
  • a torque device is arranged to restrict axial movement of the drive nut along the shaft until a predetermined torque is applied to the nut .
  • this torque device is in the form of a torque pin which extends radially through the nut and into the shaft, and wherein the torque pin is operative to shear on the application of a predetermined torque to the nut.
  • the torque device is separate from the stop.
  • the torque device is also used as the stop thereby obviating the need for a separate lock nut .
  • the bolt In operation of a particular embodiment of the self drilling rock bolt, the bolt is secured to a drilling apparatus, via the drive nut, which rotates the rock bolt in the first direction. Drilling fluid is pumped to the first end to flush the cutting surface of the rock bolt . The drilling fluid flows along a circulation path that incorporates the passage between the sleeve and the shaft . On completion of the drilling phase, the drilling apparatus then rotates the bolt in the opposite direction which causes activation of the anchoring device and in particular causes the mandrel to move axially down the bolt shaft causing the expansion element (s) to expand.
  • the threaded coupling for both the mandrel and the drive nut has the same handed thread.
  • the drive nut rotates with the shaft as relative movement is prevented by the torque pin.
  • the shaft rotates in the second direction.
  • This causes the expansion element (s) to grip the surface of the bore, or if provided, the band flaps to flare outwardly and grip the bore surface, causing the expansion element (s) and mandrel to start to slip relative to the bolt shaft.
  • This relative movement induced between the anchoring device and the shaft causes the mandrel to wind down the thread of the shaft thereby causing the expansion elements to displace radially outwardly to engage the rock surface of the drilled hole.
  • the drilling apparatus can be detached and at some later time grout can be injected into the hole to set the bolt in place.
  • This grout typically fills the entire circulation path and in one form, is supplied through the port in the irrigated drive nut.
  • the bolt can also be placed in tension by continuing to apply torque in the second direction to the drive nut.
  • the expansion elements are forced so hard against the rock wall surface that the mandrel cannot move down the shaft any further. This then effectively binds the bolt and inhibits it from rotating any further. This builds up the torque at the drive nut until it reaches a point where it will shear the torque pin thereby allowing the drive nut to move relative to the shaft. This relative movement then causes the nut to wind up the shaft .
  • the drive nut Once the drive nut is able to move along the bolt shaft, it will then move into engagement with the outer face of the rock strata (either directly or through a bearer plate) which will then enable the bolt to be placed in tension as the distance of the bolt between the drive nut and the anchoring device is shortened. This places the rock strata in compression and causes the sleeve to collapse (typically in a concertina fashion) as a result of this shortening of the distance. Once the bolt is under sufficient tension, the drilling apparatus can then be removed and the final stage of setting the bolt in place by the introduction of the grout through the inner passage of the bolt can then be performed.
  • Fig. 1 is a schematic perspective view of a self drilling rock bolt
  • Fig. 2 is an exploded view of a first end of the rock bolt of Fig. 1;
  • Fig. 3 is a perspective view of the first end of the rock bolt of Fig. 1;
  • Fig. 4 is a sectional view of the first end of the rock bolt of Fig. 1 when located in rock strata;
  • Fig. 5 is a detailed view of an anchor band of the rock bolt of Fig. 1 in a collapsed condition
  • Fig. 6 is the anchor band of Fig. 5 in an expanded condition
  • Fig. 7 is a perspective view of a second end of the rock bolt of Fig. 1;
  • Fig. 8 is a perspective view of an irrigated drive nut located at the second end of rock bolt of Fig. 7;
  • Fig. 9 is a sectional view of the second end of the rock bolt of Fig. 7 when located in rock strata;
  • Fig. 10 is a variation of the rock bolt of Fig. 1.
  • Fig. 1 illustrates a self drilling rock bolt 10 which incorporates a first (drilling) end 11 and a second (nut) end 12 and a shaft 13 which extends between the opposite ends 11, 12.
  • the shaft 13, which is typically made from steel, is solid along a major (second) part of its length and incorporates an inner passage 14 (see Fig. 4) along a distal (first) part of bolt adjacent the drilling end.
  • the inner passage communicates with the exterior of the shaft at two places; though a lateral port 60, and through an end port 61.
  • the self drilling rock bolt 10 is connected to a drilling apparatus (not shown) and acts as a drill rod to drill a hole 100 (see Figs. 4 and 9) into rock strata 500. Thereafter, the rock bolt 10 is secured in place as will be explained in more detail below to provide support for the rock strata 500.
  • the drilling end 11 incorporates a drill bit 15 incorporating a drill tip 16 at a distal end thereof and an anchoring device 23 which in use is arranged to retain the bolt in a drilled hole.
  • the anchoring device 23 extends along the first part of the bolt and is used to retain the bolt 10 in the drilled hole so as to temporarily secure the rock bolt in place prior to the introduction of grout into the hole 100 to permanently fix the bolt in place and/or to tension the bolt so as to place the rock strata 500 in compression.
  • the drill bit 15 includes a bit body 17 which includes the drill tip 16 at its outer end and a drill bit shank 18 which incorporates an external thread 22 on its outer surface.
  • a passage 19 extends from the distal tip of the shank 18 through to the distal end of the bit body 17. This passage 19 is arranged to be in fluid communication with end port 61 of the inner passage 14 of the shaft when the drill bit 15 is secured to the shaft end 20 (as best seen in Fig. 4) .
  • the shaft end 20 includes an inner thread 21 (see Fig. 4) which is complementary to the external thread 22 on the drill bit shank 18. As such, the drill bit 15 can be simply screwed on to shaft end 20 of the shaft 13.
  • the drilling apparatus typically induces right hand rotation to the drill shaft.
  • the threaded coupling between the drill bit 15 and the shaft 13 is a right handed thread so as to tend to cause the threaded coupling between the drill bit and shaft to tighten during a drilling operation.
  • the anchoring device 23 is disposed below the drill bit 15 and includes a pair of expansion elements 24 which are designed to be caused to move outwardly from a retracted position as illustrated in the drawings to an expanded condition (not shown) wherein the expansion elements 24 engage the wall 101 of the drilled hole 100.
  • the expansion elements 24 are interconnected by a connector 25.
  • This connector is typically made from spring steel and includes a body section 26 and connecting legs 27.
  • the connecting legs 27 are welded (or otherwise fixed) to a proximal end 28 of the expansion elements 24.
  • the body 26 of the connector is arranged to be captured between the drill bit 15 and shaft end 20 in a manner that allows the expansion elements to rotate about the shaft axis 20 but prevents them from moving axially along the bolt shaft .
  • the anchoring device 23 further includes a mandrel 29 which includes opposite inclined surfaces 30 and 31.
  • the mandrel 29 includes a head portion 32 and two depending legs 33 and 34 with opposite faces of the head portion 32 and opposite edge surfaces of the legs 33 and 34 forming respective ones of the inclined surfaces 30 and 31.
  • the mandrel is arranged so that the inclined surfaces 30 and 31 are generally flat and designed ' to abut with inner surfaces 35 of the expansion elements 24 in a manner such that relative movement of the mandrel towards the nut end 12 of the shaft causes the expansion elements to move from their retracted position to their extended position.
  • the mandrel is coupled to the bolt shaft which in the illustrated arrangement is through a threaded coupling with an internal thread 36 formed in an inner bore 37 in the head portion 32 of the mandrel 29 and an external thread 38 formed on the bolt shaft 13.
  • the threaded coupling between the mandrel 29 and the bolt shaft 13 is a left handed thread so that when the rock bolt is undergoing a drilling operation (under right hand rotation of the shaft) , any relative motion between the mandrel and the shaft would cause the mandrel to move towards the drill end thereby ensuring that the expansion elements are not moved to their expanded condition.
  • the anchoring device 23 further comprises an anchor band 39 which is disposed around a distal end 40 of the expansion elements 24.
  • the anchor band 39 is typically made from a polymeric material and includes a band body 41 and a plurality of flaps 42 which are disposed around the periphery of the band body 41 to form a profiled surface 43.
  • This profiled surface 43 of the band 39 is arranged to adopt two conditions as best illustrated in Figs. 5 and 6.
  • the flaps 42 are folded against the band body 41. This condition occurs when the band undergoes right hand rotation as would be the case during the drilling operation.
  • the flaps 42 project outwardly from the band body 39. This occurs during the opposite rotation of the bolt shaft and is induced by the band passing over the wall surface 101 of the drilled hole under this rotation.
  • this second (or expanded) condition there is a greater tendency for the band to engage wall surface of the drilled hole.
  • the anchoring device begins to slip relative to the shaft thereby inducing some relative movement. This movement, in turn causes the wedge to start winding down the shaft thereby causing the expansion elements to be displaced outwardly.
  • a self drilling rock bolt 50 is disclosed in Fig. 10 which incorporates a variation of the anchoring device 23 of the bolt 10. As the bolt 50 includes many of the features of the bolt 10, like features have been given like reference numerals.
  • an expansion assembly 51 is provided that includes the expansion elements 24 and a collar 52 disposed about the shaft 13 of the bolt 50.
  • the collar 52 functions in the same way as the connector 25 of the earlier embodiment and interconnects the proximal ends 28 of the expansion elements 24.
  • the expansion assembly 51 is orientated so that the distal ends 40 of the expansion elements face towards the drill end 11, rather than the nut end 12 as in the earlier embodiment.
  • the assembly 51 is seated on a retaining device 53 that comprises a thrust ring 54 that is axially fixed to the bolt shaft 13 and a slip ring 55 disposed between the thrust ring 54 and the collar 52.
  • the assembly 51 incorporates the mandrel 29 arranged so that its inclined flat surfaces 30 and 31 are designed to abut with inner surfaces 35 of the expansion elements 24. In this way relative rotation between the mandrel 29 and the expansion elements 24 about the shaft axis is inhibited. Further, relative movement of the mandrel 29 towards the nut end 12 of the shaft causes the expansion elements to move from their retracted position to their extended position. Furthermore, the mandrel is coupled to the bolt shaft by a threaded coupling (not shown) .
  • the threaded coupling between the mandrel 29 and the bolt shaft 13 is a left handed thread so that when the rock bolt is undergoing a drilling operation (under right hand rotation of the shaft) , any relative motion between the mandrel and the shaft would cause the mandrel to move towards the drill end thereby ensuring that the expansion elements are not moved to their expanded condition.
  • the anchor device 23 may also incorporate the band 39 to promote rotation of the expansion assembly under left hand rotation of the bolt 50. Because the mandrel 29 and the expansion assembly 51 rotate together, this rotation is translated to the mandrel 29, to activate the device 23 and cause movement of the mandrel towards the nut end 12.
  • the rock bolt 10 includes a sleeve 62 along a major part of the shaft 13.
  • the sleeve 62 extends from adjacent the anchoring device 23 (or expansion assembly 51) through to and adjacent the nut end 12.
  • the purpose of the sleeve is to provide at lease part of a circulation path to allow fluid to be passed between the nut end 12 to the drilling end 11.
  • This circulation path is provided by a passage formed between the bolt shaft 13 and the sleeve 62 as well as the inner passage 14.
  • the inner passage 14 communicates with the passage 63 formed between the shaft 13 and the sleeve 62 through the lateral port 60.
  • the sleeve 62 does not need to take any significant load, it may be made from an inexpensive material such as plastic.
  • a further advantage of making the sleeve from plastic is that it may provide a water barrier to inhibit corrosion of the steel shaft when in place.
  • the circulation path also includes an outer passage 64 formed between the sleeve 62 and the wall 101 of the drilled hole 100. This outer passage is formed by having the drill tip 16 extend radially a distance greater than the radius of the sleeve 62.
  • the sleeve 62 is sealed at its distal end 65 by a collar 66.
  • This collar 66 in the illustrated form incorporates an internal thread and is threaded onto the external thread 38 machined on the upper part of the shaft 13 .
  • the proximal end 67 of the sleeve 62 is also sealed by inter engaging with a drive coupler 43 as will be explained in further detail below.
  • Figs. 7 to 9 illustrate the nut end 12 of the rock bolt 10 that incorporates the drive coupler 43.
  • the drive coupler is disposed adjacent to the end 12 and is arranged to inter-engage with the drilling apparatus and the shaft so as to allow rotation and thrust to be imparted to the bolt shaft 13.
  • the drive coupler 43 is in the form of an irrigated drive nut 43 (as best seen in Fig. 8) which is connected to the bolt shaft 13 through a threaded coupling comprising an external thread 44 disposed on the shaft 13 and a complementary inner thread 45 disposed on an inner surface of the drive nut 43.
  • the threaded coupling in the illustrated form is a left handed thread so that during a drilling operation, the torque applied to the drive nut tends to cause it to wind off the second end of the shaft 13.
  • a stop assembly 46 is provided which is operative to inhibit axial movement of the drive nut beyond a predetermined location on the shaft.
  • this stop is in the form of a lock nut 47 which is secured to a terminal end portion 48 of the shaft which is of a reduced diameter.
  • the lock nut 47 is coupled to the terminal end portion 48 by a threaded coupling (i.e. an external thread 49 on the terminal end and a complementary inner thread 50 on the nut) that is oppositely handed to the drive nut threaded coupling.
  • the drive nut 43 is also coupled to the shaft by a torque pin 51 which is arranged to restrict relative movement of the drive nut until a predetermined torque is supplied to the nut.
  • the torque pin 51 extends radially through the nut 47 and into the shaft 13 (as best illustrated in Fig. 9) , and is operative to shear on the application of a predetermined torque to the nut. If the torque pin 51 is designed to be of sufficient strength, it can obviate the need to incorporate the lock nut 47.
  • the drive nut 43 includes an annular recess 68 and a collar 69 which is arranged to receive the proximal end 67 of the sleeve so as to seal the drive nut 43 to that end. Furthermore, the drive nut 43 further incorporates a port 70 which allows fluid to be introduced or extracted from the passage 63 disposed between the sleeve 62 and the shaft 13.
  • a bearer plate 71 and ball washer 72 may be disposed on the shaft 13 and captured by the drive nut 43.
  • the bearer plate 71 is arranged to bear against the outer face 501 of the rock strata 500.
  • the bolt 10 is secured to a drilling apparatus, via the drive nut 43, which rotates the rock bolt in the first direction.
  • Drilling fluid is pumped around the circulation passage formed by passage 63, inner passage 60, and outer passage 64 to flush the cutting surface of the rock bolt .
  • the fluid is either introduced or withdrawn from the port 70 in the irrigated drive nut 43.
  • the drilling apparatus On completion of the drilling phase, the drilling apparatus then rotates the bolt in the opposite direction.
  • the drive nut 43 rotates with the shaft 13 as relative movement is prevented by the torque pin.
  • This causes the band flaps 42 (if provided) to flare outwards causing the band to grip the wall surface 101 causing the expansion elements 24 and mandrel 29 to start to slip relative to the bolt shaft.
  • the expansion elements 24 may be arranged to grip directly on the wall surface 101 to promote the slip.
  • This relative movement induced between the anchoring device and the shaft causes the mandrel to wind down the thread of the shaft thereby- causing the expansion elements to displace radially outwardly to engage the rock surface of the drilled hole.
  • the bolt becomes firmly held in place. Accordingly if need be, the drilling apparatus can be detached and at some later time grout can be injected into the hole to set the bolt in place.
  • the bolt can be placed in tension by continuing to apply torque in the second direction to the drive nut 43.
  • the expansion elements 24 are forced so hard against the rock wall surface that the mandrel cannot move down the shaft any further. This then effectively binds the bolt and inhibits it from rotating any further. This builds up the torque at the drive nut 43 until it reaches a point where it will shear the torque pin 51 thereby letting the drive nut to move relative to the shaft. This relative movement then causes the nut to wind up the shaft .
  • the drive nut Once the drive nut is able to move along the bolt shaft, it will then move into engagement the outer face 102 of the rock strata 500 (either directly or through the bearer plate 71) which will then enable the bolt to be placed in tension as the effective length of the bolt between the drive nut and the anchoring device is shortened. This causes the sleeve 63 to collapse (typically by a concertina movement) and places the rock strata in compression. Once the bolt is under sufficient tension, the drilling apparatus can then be removed and the final stage of setting the bolt in place by the introduction of the grout through the port 70 in the drive nut 43.

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • Piles And Underground Anchors (AREA)

Abstract

Boulon d'ancrage auto-foreur (10) comprenant une tige (13), un dispositif d'ancrage (23) et un manchon (62) entourant la tige (13) sur toute sa longueur. Une première extrémité (11) du boulon possède une pointe de forage (16) pour pénétrer le rocher, et une seconde extrémité (12) est adaptée pour être raccordée à un appareil de forage afin de mettre en rotation le boulon et exercer une poussée sur ce dernier. Un passage (63) est formé entre le manchon (62) et la tige (13) pour permettre le passage d'un fluide le long de la tige. Le dispositif d'ancrage (23) a pour fonction de retenir le boulon une fois en place dans un trou foré, et comprend un mandrin (29) présentant une ou plusieurs surfaces externes inclinées (29, 30) montées sur la tige (13), ou formées d'une pièce avec celle-ci, et au moins un élément d'expansion (24) recouvrant le mandrin. Le(s) élément(s) d'expansion (24) se déplace(nt) dans le sens radial, vers l'extérieur, selon un déplacement relatif prédéterminé entre le mandrin (29) et l'élément (24).
PCT/AU2006/001670 2006-06-29 2006-11-08 Boulon d'ancrage auto-foreur Ceased WO2008000015A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2006202778 2006-06-29
AU2006202778A AU2006202778A1 (en) 2006-06-29 2006-06-29 Self drilling rock bolt

Publications (1)

Publication Number Publication Date
WO2008000015A1 true WO2008000015A1 (fr) 2008-01-03

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AU (1) AU2006202778A1 (fr)
WO (1) WO2008000015A1 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011020144A1 (fr) * 2009-08-19 2011-02-24 Peter Gray Écrou et ancre de boulon de roche
US7896580B2 (en) 2005-11-09 2011-03-01 Sandvik Intellectual Property Ab Self drilling rock bolt
WO2012012392A2 (fr) 2010-07-19 2012-01-26 Illinois Tool Works Inc. Dispositif d'ancrage
WO2012012401A2 (fr) 2010-07-19 2012-01-26 Illinois Tool Works Inc. Dispositif d'ancrage
AU2010206071B2 (en) * 2010-07-30 2012-07-12 Sandvik Intellectual Property Ab A rock bolt and an anchoring device
CN102808635A (zh) * 2012-07-20 2012-12-05 中国科学院武汉岩土力学研究所 一种胀壳式内锚头预应力锚杆及其安装使用方法
US8403600B2 (en) 2006-11-15 2013-03-26 Sandvik Intellectual Property Ab Drilling tool, a self-drilling rock bolt, a drill bit, an anchoring device for a self-drilling rock bolt, a shaft for a drilling tool and an end coupling for a drilling tool
CN103195059A (zh) * 2013-03-27 2013-07-10 钟利刚 自定位式弹簧导流板带筋水泥土地锚钻头及其施工方法
CN106320610A (zh) * 2016-10-31 2017-01-11 洛阳中岩工程材料有限公司 一种顶环式涨壳锚头
CN110836122A (zh) * 2019-12-16 2020-02-25 湖南科技大学 可随岩层间错动而错动的穿层锚杆装置及安装方法
CN119287890A (zh) * 2024-11-29 2025-01-10 华侨大学 一种可变直径拉压复合型抗浮锚杆及其施工方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2008230002B2 (en) * 2008-06-25 2012-05-03 Sandvik Intellectual Property Ab A cuttable drilling tool, and a cuttable self drilling rock bolt

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2171985A (en) * 1938-07-28 1939-09-05 Star Expansion Bolt Company Bolt anchor
US4026186A (en) * 1976-02-23 1977-05-31 Illinois Tool Works Inc. Self-drilling one-piece masonry anchor
US6793445B1 (en) * 1999-03-31 2004-09-21 Paul Charlton Method and apparatus for insertion of rock bolts

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2171985A (en) * 1938-07-28 1939-09-05 Star Expansion Bolt Company Bolt anchor
US4026186A (en) * 1976-02-23 1977-05-31 Illinois Tool Works Inc. Self-drilling one-piece masonry anchor
US6793445B1 (en) * 1999-03-31 2004-09-21 Paul Charlton Method and apparatus for insertion of rock bolts

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7896580B2 (en) 2005-11-09 2011-03-01 Sandvik Intellectual Property Ab Self drilling rock bolt
US8403600B2 (en) 2006-11-15 2013-03-26 Sandvik Intellectual Property Ab Drilling tool, a self-drilling rock bolt, a drill bit, an anchoring device for a self-drilling rock bolt, a shaft for a drilling tool and an end coupling for a drilling tool
WO2011020144A1 (fr) * 2009-08-19 2011-02-24 Peter Gray Écrou et ancre de boulon de roche
WO2012012392A2 (fr) 2010-07-19 2012-01-26 Illinois Tool Works Inc. Dispositif d'ancrage
WO2012012401A2 (fr) 2010-07-19 2012-01-26 Illinois Tool Works Inc. Dispositif d'ancrage
AU2010206071B2 (en) * 2010-07-30 2012-07-12 Sandvik Intellectual Property Ab A rock bolt and an anchoring device
CN102808635A (zh) * 2012-07-20 2012-12-05 中国科学院武汉岩土力学研究所 一种胀壳式内锚头预应力锚杆及其安装使用方法
CN103195059A (zh) * 2013-03-27 2013-07-10 钟利刚 自定位式弹簧导流板带筋水泥土地锚钻头及其施工方法
CN103195059B (zh) * 2013-03-27 2015-08-26 钟利刚 一种使用自定位式弹簧导流板带筋水泥土地锚钻头的施工方法
CN106320610A (zh) * 2016-10-31 2017-01-11 洛阳中岩工程材料有限公司 一种顶环式涨壳锚头
CN110836122A (zh) * 2019-12-16 2020-02-25 湖南科技大学 可随岩层间错动而错动的穿层锚杆装置及安装方法
CN119287890A (zh) * 2024-11-29 2025-01-10 华侨大学 一种可变直径拉压复合型抗浮锚杆及其施工方法

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