SE1451381A1 - Rock bolt and method of installing a rock bolt - Google Patents

Rock bolt and method of installing a rock bolt Download PDF

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Publication number
SE1451381A1
SE1451381A1 SE1451381A SE1451381A SE1451381A1 SE 1451381 A1 SE1451381 A1 SE 1451381A1 SE 1451381 A SE1451381 A SE 1451381A SE 1451381 A SE1451381 A SE 1451381A SE 1451381 A1 SE1451381 A1 SE 1451381A1
Authority
SE
Sweden
Prior art keywords
bolt
tubular expandable
protecting sleeve
bolt portion
rock
Prior art date
Application number
SE1451381A
Other languages
English (en)
Other versions
SE540189C2 (en
Inventor
Mario Bureau
Chris Cranford
Paul Lambert
Original Assignee
Atlas Copco Canada Inc
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 Atlas Copco Canada Inc filed Critical Atlas Copco Canada Inc
Publication of SE1451381A1 publication Critical patent/SE1451381A1/sv
Publication of SE540189C2 publication Critical patent/SE540189C2/en

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Classifications

    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/0026Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
    • E21D21/0033Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts having a jacket or outer tube
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/0026Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
    • E21D21/004Bolts held in the borehole by friction all along their length, without additional fixing means
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/008Anchoring or tensioning means
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16BDEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B13/00Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
    • F16B13/12Separate metal or non-separate or non-metal dowel sleeves fastened by inserting the screw, nail or the like
    • F16B13/122Separate metal or non-separate or non-metal dowel sleeves fastened by inserting the screw, nail or the like made from a sheet-metal blank

Landscapes

  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Piles And Underground Anchors (AREA)
  • Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)

Description

15 20 25 30 AIM AND MOST IMPORTANT FEATURES OF THE INVENTION It is an aim of the present invention to provide a rock reinforcement bolt according to the above, which addresses issues with the background art in respect of rock reinforcement of rock faces where problematic rock movements can be expected.
This aim is achieved according to the invention by a rock reinforcement bolt of the kind indicated above wherein; at least one protecting sleeve is arranged on an outside of the tubular expandable bolt portion, and each protecting sleeve is displaceable along the extension of the tubular expandable bolt portion and is fastenable thereon in a chosen longitudinal position on the tubular expandable bolt portion.
Hereby the user can adapt and customize the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at the particular site.
Since the invention includes using an expandable rock reinforcement bolt, the performance of the bolt does not depend on grout or resin and problems associated with attempting to fill bore holes with grout, where the bore hole connects to grout-swallowing crevasses, wherein infinite amounts of grout can disappear. Using protecting sleeve (~s), according to the invention, increases bolt energy absorption capabilities and bolt ability to tackle considerable movements in areas subjected to relative rock movement in the bolt hole area.
Existing solutions have no provisions for increasing resistance in such areas that could easily lead to failure of the background art reinforcements, in particular since mostly the displacement between parts of rock induces tensile effects to the installed bolts. The existing solutions using grout cement or resin which, as is mentioned above, is often lost in 10 15 20 25 30 cracks or rock mass joints, thus reduces considerably the efficiency of such solutions.
Through the invention it is possible to detect problematic positions in a bore hole and to isolate the tubular expandable bolt portion from the bolt hole wall in that very position (-s). This is a great advantage since use of expandable bolts can be made secure thus ensuring good anchorage in all ground conditions without using resin or cement. It also allows flexibility in allowing localization of the protecting sleeves allowing energy absorption to take place and to match rock mass conditions just before installation of the bolt. It further allows flexibility in energy absorbents capacity by allowing selection of sleeve dimensions and lengths or adding adjacent sleeves to the tubular expandable bolt portion.
Increase of resistance in areas expected to move in the rock can be further enhanced by selecting high strength material sleeves.
The capacity to absorb energy can be modulated by the length of the sleeve used, material thickness or by using more than one sleeve next to one another. For example, for one segment, if the bolt has a capacity of 200 kN, the sleeve measures 0,5 m and the steel elasticity is 20% for such length, the energy absorbance will be equal to 200 kN X 0,5 m X 20% = 20 kJ. This figure can be proportionally modulated by using a shorter or longer sleeve or increasing or reducing adjacent sleeves.
The invention makes it possible to localize and position sleeves to match rock mass conditions to zones of expected fracture or convergence immediately before installation. This can be made by per se known investigations of rock bodies or simply by inspecting the particular bore hole. lO 15 20 25 30 The sleeves considerably increase bolt ability to withstand otherwise harmful rock movements. The sleeves can be made from many materials and high strength steel sleeves can be used to further increase resistance.
It is preferred that each protecting sleeve is fastenable on the outside of the tubular expandable bolt portion by means of at least one from the group: a locking ring, a locking clip, a locking clamp, a looking band, a locking tape, an adhesive medium. These elements are then arranged so as to engage the outside of the tubular expandable bolt portion and the sleeve.
The material in the protecting sleeve is advantageously a metal, a ceramic or a synthetic material. Steel is advantageous and in particular high resistance steel. It is also, however, possible to use sleeves from other suitable materials.
In any case, even in respect of more easily deformable protecting sleeves, at the occurrence of a rock movement resulting in tensile or tearing action to the bolt, the bolt will have the ability to have tensile deformation extended to virtually a whole sleeve length (or plural sleeve lengths in case of plural adjacent positioned sleeves) because the tubular expandable bolt portion being allowed to elongate evenly over that length since it is isolated from frictional contact with the bolt hole wall.
The protecting sleeve length is preferably related to a width of an expected rock movement zone so as to adapt to prevailing conditions.
If necessary, more than one protecting sleeve is advantageously positioned adjacent to each other on the tubular expandable bolt portion in order to cover wide problem areaS . 10 15 20 25 30 One important aspect of the invention is that it has been made possible to control the installed bolt or parts thereof so as to provide “full anchorage capacity” or not vis-à~vis the bolt hole wall as required and desired.
Below a certain length of engagement between the fluid expandable bolt and the bolt hole wall, what is here called “anchorage limit length", the bolt will not reach full anchorage capacity, which will result in sliding movement of the bolt inside the hole in case of loads in excess of an anchorage limit.
According to this aspect of the invention, this could be exploited by positioning sufficiently long protecting sleeves on a bolt at chosen positions and let remaining exposed portion or portions (which will come into engagement with the hole wall after expansion) of the bolt have length/lengths being below said anchorage limit length. This could be advantageous in many applications, in particular where great movements are expected during a seismic event, since according to this aspect, the exposed portion or portions in engagement with the hole wall will slide inside the bore hole at the occurrence of greater loads. This sliding movement will absorb energy of the seismic event by way of a friction force between the bolt and the surrounding bolt hole wall. The bolt will never reach a point of failure because due to the lowered anchorage below said anchorage limit, the bolt will maintain its integrity and continue to be functional to hold the surrounding fractured rock.
As an example only, in normal conditions using a Swellex ® bolt expanded to the set pressure value in solid rock and being tested for different lengths of protecting sleeves, it has been demonstrated that the anchorage limit length is close to 0,5 meters. Lengths below that value will result in sliding of the bolt before failure when subjected to a high load, 10 15 20 25 30 lengths above that value will result in failure of the bolt before sliding when subjected to a high load. Maximum load absorbed before bolt failure has been about 240 kN for the tested bolts. This means that sliding of a bolt with reduced engagement length below the anchorage limit length will start at loads below 240 kN. Typically the tested bolt is intended for loads up to 200 kN. In order to ensure security, it is recommended to perform tests for the chosen bolt in the rock in question.
The corresponding features and advantages relating to the bolt apply in respect to a method including the steps: arranging at least one protecting sleeve on an outside of the tubular expandable bolt portion, displacing each protecting sleeve along the extension of the tubular expandable bolt portion and fastening it thereon in a chosen longitudinal position on the tubular expandable bolt portion, inserting the rock reinforcement bolt into said bore hole, and subjecting the tubular expandable bolt portion to an inside overpressure for expanding purposes. Further advantages apply to preferred optional aspects of the method corresponding to the above.
Corresponding advantages as above apply for the inventive method.
The invention also concerns a protecting sleeve being dimensioned to be positioned on an outside of the tubular expandable bolt portion and inside a bolt hole, the protecting sleeve having inside dimensions so as to be displaceable along the extension of the tubular expandable bolt portion and be fastenable thereon in a chosen longitudinal position on the tubular expandable bolt portion.
BRIEF DESCRIPTION OF DRAWINGS The invention will now be described in greater detail with reference to the annexed drawings, wherein: 10 15 20 25 30 Fig. 1 shows a rock bolt according to the invention with a displaceable protecting sleeve, Fig. 2 shows the rock bolt according to Fig. 1 with the protecting sleeve fastened in a chosen position, Fig. 3 shows the rock bolt in Figs. 1 and 2 inserted into a bore hole and with a connection established with a pressure source, Fig. 4 shows the rock bolt of Fig. 3 in the expanded state and installation completed, Fig. 5 shows a cross section of the tubular expandable bolt portion of the rock bolt in its initial condition, Fig. 6 shows the tubular expandable bolt portion in its expanded condition, Fig. 7 shows a cross section of the rock bolt according to the invention with a section through a region where a protective sleeve covers a part of the tubular expandable bolt portion, Figs. 8-10 show different alternatives for securing one or more protecting sleeves on the tubular expandable bolt portion, and Fig. 11 indicates a method sequence according to the invention.
DESCRIPTION OF EMBODIMENTS Fig. 1 shows a rock reinforcement bolt 1 having a tubular expandable bolt portion 2 which is of a kind having a closed cross section and which in its non-expanded condition comprises an elongated tube having a deep continuous longitudinal depression extending inwardly of the bolt to the axis of the bolt and extending longitudinally of the tube. The tube has a closed cross sectional portion in the area of the deep longitudinal depression and the tube is closed at the distal end thereof. The radial dimensions of the non expanded 10 15 20 25 30 portion are made such that it is easy to insert into a bore hole.
A protecting sleeve 5 is displaceable along the length of the portion 2. A connecting portion 3 at a proximal end of the bolt 1 is for the connection of a pressure source to an inside of the tubular expandable bolt portion. A support portion 4 is arranged for support against a rock face (12 in Fig.3) in the region of a mouth of a bore hole. 6 indicates a distal end portion.
Fig. 2 shows the rock bolt according to Fig. 1 with the protecting sleeve fastened in a chosen position by means of locking elements such as clips, bands etc. It is within the scope of the invention also to use adhesives such as glues or tapes to lock the protecting sleeve at the chosen position on the bolt.
Fig. 3 shows the rock bolt in Figs. 1 and 2 inserted into a bore hole 8 and with a connection 9 established with a pressure source 10 for subsequent expansion of the bolt. 11 indicates a crack in the rock body where a relative movement of rock portions on either side of the crack 11 can be expected. The positioning of the protecting sleeve bridging the crack supports the relatively soft and sensitive material of the bolt. 11 indicates a support plate being applied against the rock face 12 in a per se known manner.
Fig. 4 shows the rock bolt of Fig. 3 in the expanded state and with the installation completed. The portions 2a and 2b only of the tubular expandable bolt portion 2 have been regularly expanded.
Fig. 5 shows a cross section of the tubular expandable bolt portion 2 of the rock bolt in its initial condition inside a bore hole 8.
In Fig. 6 the tubular expandable bolt portion 2 has been subjected to internal pressure from a pressure fluid source 10 l5 20 25 30 such that it has been made to expand and to tightly contact the inside of the bore hole 8. The length of the material in the cross section 2 exceeds the inner circumference of the bore hole 8 so as to ensure proper and permanent contact.
Fig. 7 shows a cross section through the rock bolt according to the invention in a region where it is provided with a protecting sleeve 5 surrounding the tubular expandable bolt portion 2. The protecting sleeve, as discussed above, thus ensures that the part of the bolt being inside the sleeve is isolated from the bolt hole wall and thereby is allowed to lengthen over the entire length of the sleeve or sleeves.
Hereby the tensile stress caused by bolt elongation, when there is a movement in the rock in the region of the bolt hole, will become lower for a bolt according to the invention compared to a conventional bolt where a corresponding rock activity would result in higher tensile stress since the bolt elongation would be concentrated to a shorter portion of the bolt.
For the purpose of protection, the protecting sleeve is made in a resistant material such as steel which has the properties of resisting movements of rock portions.
In Fig. 8 is shown an alternative manner of fastening the protecting sleeve 5 to the tubular expandable bolt portion 2 by means of only one clamping and locking element 7 which is positioned on an outside of the protecting sleeve 5 as seen in an insertion direction being to the right in Fig. 8. It is understood that during insertion of the rock bolt 1 of Fig. 8 into a bore hole, the locking element 7 prevents sliding of the protecting sleeve 5 from the chosen direction and in this case no additional locking element is necessary at position 17 on the inside of the protecting sleeve 5. lO l5 20 25 30 lO Fig. 9 shows an example where two protecting sleeves 5a and 5b are positioned adjacent to one another and being secured by locking elements 7 such as clips.
Fig. 10 shows a further embodiment wherein two protecting sleeves Sa and 5b are separated in order to protect from cracks in separate position in a bore hole. Each protecting sleeve is fastened to the tubular expandable bolt portion 2 by means of locking elements 7 on both sides. Expansion of rock bolt 1 in Fig. 10 will take place in three areas as indicated with numeral 18.
The invention can be modified within the scope of the annexed claims. Also other kinds of fluid expandable rock bolts can be used even if the one shown in the drawings is highly preferred. The material of the protecting sleeves can be adapted to the expected loads and the material and the material thickness can be dimensioned accordingly. Suitably, the sleeve is made from a material from the group: metal, ceramic material, synthetic material. The sleeves are preferably continuous pipes with circular cross section, but also slotted tubes are within the invention.
Also the length of the protecting sleeves can be adapted to expected conditions in order for example to adapt to longer or shorter areas of expected loads. It is here referred to the above discussion about dimensioning and positioning the sleeves so as to allow energy absorbing sliding movements of the bolt inside the bolt hole.
An exemplary method sequence according to the invention will be described at the background of Fig 11; - Position 20 indicates start of the sequence.
- Position 21 indicates arranging at least one protecting sleeve on an outside of the tubular expandable bolt portion.
- Position 22 indicates displacing each protecting sleeve along the extension of the tubular expandable bolt portion and lO ll fastening it thereon in a chosen longitudinal position on the tubular expandable bolt portion corresponding to an expected rock movement zone.
- Position 23 indicates inserting the rock reinforcement bolt into a bore hole.
- Position 24 indicates subjecting the tubular expandable bolt portion to an inside overpressure for expanding purposes.
- Position 25 indicates fastening each protecting sleeve on the outside of the tubular expandable bolt portion with fastening means.
- Position 26 indicates end of the sequence.

Claims (18)

10 15 20 25 30 12 Claims:
1. A rock reinforcement bolt (1) having: - a tubular expandable bolt portion (2) with a closed cross section for expansion inside a bore hole (8), the tubular expandable bolt portion (2) having a longitudinal extension, - a connecting portion (3) for the connection of a pressure source to an inside of the tubular expandable bolt portion, and - a support portion (4, 13) for support against a rock face (12) in the region of a mouth of the bore hole, characterized in - that at least one protecting sleeve (5, 5a, 5b) is arranged on an outside of the tubular expandable bolt portion (2), and - that each protecting sleeve (5, Sa, 5b) is displaceable along the extension of the tubular expandable bolt portion (2) and is fastenable thereon in a chosen longitudinal position on the tubular expandable bolt portion.
2. The bolt according to claim 1, wherein each protecting sleeve (5, 5a, 5b) is fastenable on the outside of the tubular expandable bolt portion (2) by means of at least one (7) from the group: a locking ring, a locking clip, a looking clamp, a locking band, a looking tape, an adhesive medium being arranged so as to engage the outside of the tubular expandable bolt portion.
3. The bolt according to claim 1 or 2, wherein the material in the protecting sleeve (5, 5a, 5b) is any one from the group: metal, ceramic material, synthetic material. lO 15 20 25 30 13
4. The bolt according to claim 3, wherein the material is high resistance steel.
5. The bolt according to any one of the claims 1 - 4, wherein protecting sleeve (5, Sa, Sb) length is related to a width of an expected rock movement zone.
6. The bolt according to any one of the claims 1 - 5, wherein more than one protecting sleeve (S, Sa, Sb) are positioned adjacent to each other on the tubular expandable bolt portion (2).
7. The bolt according to any one of the claims 1 - 6, wherein at least one protecting sleeve (S, Sa, Sb) is positioned such that a length of at least one remaining portion of the tubular expandable bolt portion not being covered by a protecting sleeve is below an anchorage limit length.
8. A method for installing a rock reinforcement bolt (1) having: - a tubular expandable bolt portion (2) with a closed cross section for expansion inside a bore hole (8), the tubular expandable bolt portion having a longitudinal extension, - a connecting portion (3) for the connection of a pressure source to an inside of the tubular expandable bolt portion, and - a support portion (4, 13) for support against a rock face (12) in the region of a mouth of the bore hole, the method including the steps: - arranging at least one protecting sleeve (S, Sa, Sb) on an outside of the tubular expandable bolt portion (2), - displacing each protecting sleeve (S, Sa, Sb) along the extension of the tubular expandable bolt portion and fastening 10 15 20 25 30 14 it thereon in a chosen longitudinal position on the tubular expandable bolt portion, - inserting the rock reinforcement bolt into said bore hole (8), and - subjecting the tubular expandable bolt portion (2) to an inside overpressure for expanding purposes.
9. The method according to claim 8, further including the step: - fastening each protecting sleeve (5, 5a, 5b) on the outside of the tubular expandable bolt portion (2) by means of at least one from the group: a locking ring, a looking clip, a looking clamp, a locking band, a locking tape, an adhesive medium so as to engage the outside of the tubular expandable bolt portion.
10. The method according to claim 8 or 9, further including the step: - dimensioning protecting sleeve (5, 5a, 5b) length so as to relate to a width of an expected rock movement zone.
11. ll. The method according to claim 8, 9 or 10, further including the step: - positioning more than one protecting sleeve (5, Sa, 5b) adjacent to each other on the tubular expandable bolt portion.
12. The method according to any one of the claims 8 - ll, further including the step: - positioning at least one protecting sleeve (5, Sa, 5b) such that a length of at least one remaining portion of the tubular expandable bolt portion not being covered by a protecting sleeve is below an anchorage limit length. 10 15 20 25 30 15
13. A protecting sleeve for a rock reinforcement bolt (1) having: ~ a tubular expandable bolt portion (2) with a closed cross section for expansion inside a bore hole (8), the tubular expandable bolt portion (2) having a longitudinal extension, - a connecting portion (3) for the connection of a pressure source to an inside of the tubular expandable bolt portion, and - a support portion (4, 13) for support against a rock face (12) in the region of a mouth of the bore hole, characterized in - that the protecting sleeve (5, 5a, 5b) is dimensioned to be positioned on an outside of the tubular expandable bolt portion (2) and inside a bolt hole, and - that the protecting sleeve (5, 5a, 5b) has inside dimensions so as to be displaceable along the extension of the tubular expandable bolt portion (2) and be fastenable thereon in a chosen longitudinal position on the tubular expandable bolt portion.
14. The sleeve according to claim 13, wherein it is fastenable on the outside of the tubular expandable bolt portion (2) by means of at least one (7) from the group: a locking ring, a locking clip, a locking clamp, a locking band, a locking tape, an adhesive medium for co-operation with the sleeve.
15. The sleeve according to claim 13 or 14, wherein it is made from a material from the group: metal, ceramic material, synthetic material.
16. The sleeve according to claim 15, wherein the material is 10 16 high resistance steel.
17. The sleeve according to any one of the claims 13 - 16, wherein protecting sleeve (5, 5a, 5b) length is related to a width of an expected rock movement zone.
18. The sleeve according to any one of the claims 13 - 17, wherein it is dimensioned such that a length of at least one remaining portion of the tubular expandable bolt portion not being covered by a protecting sleeve is below an anchorage limit length.
SE1451381A 2012-05-22 2012-05-22 Rock bolt and method of installing the rock bolt and a protecting sleeve for it SE540189C2 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CA2012/050338 WO2013173901A1 (en) 2012-05-22 2012-05-22 Rock bolt and method of installing a rock bolt

Publications (2)

Publication Number Publication Date
SE1451381A1 true SE1451381A1 (sv) 2014-11-18
SE540189C2 SE540189C2 (en) 2018-04-24

Family

ID=49622955

Family Applications (1)

Application Number Title Priority Date Filing Date
SE1451381A SE540189C2 (en) 2012-05-22 2012-05-22 Rock bolt and method of installing the rock bolt and a protecting sleeve for it

Country Status (3)

Country Link
CA (1) CA2872252C (sv)
SE (1) SE540189C2 (sv)
WO (1) WO2013173901A1 (sv)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111911191A (zh) * 2020-07-15 2020-11-10 中国矿业大学 一种过泥化松散顶板巷道的控制方法

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Publication number Priority date Publication date Assignee Title
US9677399B2 (en) * 2013-07-12 2017-06-13 Minova International Limited Yieldable rock anchor
CN106714842B (zh) 2014-09-03 2021-07-02 理森制药股份公司 包含双重PI3K δ-γ激酶抑制剂和皮质类固醇的治疗方法及组合物
PE20180749A1 (es) * 2015-07-10 2018-04-27 Epiroc Canada Inc Refuerzo de cizallamiento y tension para perno inflable
CZ2016244A3 (cs) 2016-04-28 2017-06-28 Dsi Underground Ip Holdings Luxembourg Sarl Rozpínatelný horninový svorník s indikátorem upnutí
CN111965254A (zh) * 2019-11-05 2020-11-20 中国葛洲坝集团第二工程有限公司 长外露锚杆无损检测方法
AU2021221472A1 (en) * 2021-08-24 2023-03-16 Fci Holdings Delaware, Inc. Dynamic rockbolt

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SE427764B (sv) * 1979-03-09 1983-05-02 Atlas Copco Ab Bergbultningsforfarande jemte rorformig bergbult
SE8106165L (sv) * 1981-10-19 1983-04-20 Atlas Copco Ab Forfarande for bergbultning och bergbult
AU2003263117A1 (en) * 2002-08-19 2004-03-03 Brendan Robert Crompton Rock bolt
WO2011087948A1 (en) * 2010-01-14 2011-07-21 Anthony John Spencer Spearing Self-drilling expandable bolt
US9062547B2 (en) * 2010-06-04 2015-06-23 Fci Holdings Delaware, Inc. Expandable bolt with shielded tip

Cited By (1)

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Publication number Priority date Publication date Assignee Title
CN111911191A (zh) * 2020-07-15 2020-11-10 中国矿业大学 一种过泥化松散顶板巷道的控制方法

Also Published As

Publication number Publication date
SE540189C2 (en) 2018-04-24
WO2013173901A1 (en) 2013-11-28
CA2872252C (en) 2019-06-18
CA2872252A1 (en) 2013-11-28

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