CA2872252C - Rock bolt and method of installing a rock bolt - Google Patents
Rock bolt and method of installing a rock bolt Download PDFInfo
- Publication number
- CA2872252C CA2872252C CA2872252A CA2872252A CA2872252C CA 2872252 C CA2872252 C CA 2872252C CA 2872252 A CA2872252 A CA 2872252A CA 2872252 A CA2872252 A CA 2872252A CA 2872252 C CA2872252 C CA 2872252C
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- Canada
- Prior art keywords
- bolt
- rock
- tubular expandable
- protecting sleeve
- bolt portion
- 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.)
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- 239000011435 rock Substances 0.000 title claims abstract description 141
- 238000000034 method Methods 0.000 title claims abstract description 17
- 230000002787 reinforcement Effects 0.000 claims abstract description 40
- 239000000463 material Substances 0.000 claims description 22
- 229910000831 Steel Inorganic materials 0.000 claims description 13
- 239000010959 steel Substances 0.000 claims description 13
- 206010057175 Mass conditions Diseases 0.000 claims description 9
- 238000002835 absorbance Methods 0.000 claims description 8
- 238000010521 absorption reaction Methods 0.000 claims description 8
- 239000000853 adhesive Substances 0.000 claims description 5
- 230000001070 adhesive effect Effects 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 4
- 229920002994 synthetic fiber Polymers 0.000 claims description 4
- 229910010293 ceramic material Inorganic materials 0.000 claims description 3
- 238000009434 installation Methods 0.000 description 5
- 239000012530 fluid Substances 0.000 description 4
- 239000011440 grout Substances 0.000 description 4
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000004568 cement Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 241001274613 Corvus frugilegus Species 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000004807 localization Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
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
- E21D21/0033—Anchoring-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
-
- 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
-
- 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
- E21D21/004—Bolts held in the borehole by friction all along their length, without additional fixing means
-
- 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
- F16B13/12—Separate metal or non-separate or non-metal dowel sleeves fastened by inserting the screw, nail or the like
- F16B13/122—Separate 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)
Abstract
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. At least one protecting sleeve (5, 5a, 5b) is arranged on an outside of the tubular expandable bolt portion (2), and each protecting sleeve (5, 5a, 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. The invention also relates to a method for installing a rock reinforcement bolt (1) and a protecting sleeve.
Description
J.
ROCK BOLT AND METHOD OF INSTALLING A ROCK BOLT
FIELD OF THE INVENTION
The invention relates to a rock reinforcement bolt having a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, the bolt further having a connecting portion for the connection of a pressure source and a support portion. The invention also relates to a method of installing a rock reinforcement bolt as above_ BACKGROUND OF THE INVENTION
Rook reinforcement bolts are used for securing roof and walls in tunnels and in mines against instable rock which might jeopardize safety of operators and machines inside such spaces.
Basically, bolts used for rock reinforcement purposes can be categorized in a number of categories; grouted bolts, mechanically expandable bolts and fluid expandable bolts.
There are also available hybrids and combinations of these basic categories.
In particularly unstable rock wherein great relative movements of rock portions of a rock mass to be secured can be expected, the bolt installation has to be adapted for example by varying distribution of bolts and bolt lengths.
As examples of the background art can be mentioned WO
2005/113939 Al, wherein a length of a tubular expandable bolt portion is determined so as to allow sliding of the bolt portion in case of excessive loads. WO 03/062599 Al, wherein at least one expandable element is included in a boring rod of a boring device. WO 200B/019409 Al, which relates to a friction bolt and expansion adaptor for the bolt.
ROCK BOLT AND METHOD OF INSTALLING A ROCK BOLT
FIELD OF THE INVENTION
The invention relates to a rock reinforcement bolt having a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, the bolt further having a connecting portion for the connection of a pressure source and a support portion. The invention also relates to a method of installing a rock reinforcement bolt as above_ BACKGROUND OF THE INVENTION
Rook reinforcement bolts are used for securing roof and walls in tunnels and in mines against instable rock which might jeopardize safety of operators and machines inside such spaces.
Basically, bolts used for rock reinforcement purposes can be categorized in a number of categories; grouted bolts, mechanically expandable bolts and fluid expandable bolts.
There are also available hybrids and combinations of these basic categories.
In particularly unstable rock wherein great relative movements of rock portions of a rock mass to be secured can be expected, the bolt installation has to be adapted for example by varying distribution of bolts and bolt lengths.
As examples of the background art can be mentioned WO
2005/113939 Al, wherein a length of a tubular expandable bolt portion is determined so as to allow sliding of the bolt portion in case of excessive loads. WO 03/062599 Al, wherein at least one expandable element is included in a boring rod of a boring device. WO 200B/019409 Al, which relates to a friction bolt and expansion adaptor for the bolt.
2 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
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
3 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.
=
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.
=
4 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 fastenahle 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 locking 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.
Cl'. 02872252 2014-10-29 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-a-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 he functional to hold the surrounding fractured rock.
As an example only, in normal conditions using a Swellex 0 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, 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.
Hence, according to a broad aspect, the invention provides a rock reinforcement bolt for rock reinforcement of rock faces where problematic rock movements can be expected, the rock reinforcement bolt having: a tubular expandable bolt 6a portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and a support portion for support against a rock face in a region of a mouth of the bore hole, wherein the rock reinforcement bolt has the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site, and wherein at least one protecting sleeve is arranged on an outside of the tubular expandable bolt portion, the protecting sleeve being made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt ability to tackle movements in areas subjected to relative rock movement in the bolt hole, and wherein 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.
According to another broad aspect, the invention relates to a method for installing a rock reinforcement bolt for rock reinforcement of rock faces where problematic rock movements can be expected, the method including: providing a rock reinforcement bolt having: a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and a support portion for support against a rock face in a region of a mouth of the bore hole, arranging at least 6b one protecting sleeve on an outside of the tubular expandable bolt portion the protecting sleeve being made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt ability to tackle movements in areas subjected to relative rock movement in the bolt hole, 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 the bore hole, and subjecting the tubular expandable bolt portion to an inside overpressure for expanding purposes, wherein the rock reinforcement bolt is given the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is being adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site.
According to a further broad aspect, the invention provides protecting sleeve for a rock reinforcement bolt for rock reinforcement of rock faces where problematic rock movements can be expected, the rock reinforcement bolt having:
a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and a support portion for support against a rock face in a region of a mouth of the bore hole, wherein the protecting sleeve is dimensioned to be positioned on an outside of the tubular expandable bolt portion and inside a bolt hole, wherein the protecting sleeve is made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt 6c ability to tackle movements in areas subjected to relative rock movement in the bolt hole, and wherein the protecting sleeve has 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, and wherein the rock reinforcement bolt is given the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site.
BRIEF DESCRIPTION OF DRAWINGS
The invention will now be described in greater detail with reference to the annexed drawings, wherein:
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
Variants, examples and preferred embodiments of the invention are described hereinbelow. 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 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 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 well 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 3D case no additional locking element is necessary at position 17 on the inside of the protecting sleeve 5.
Fig. 9 shows an example where two protecting sleeves 5a and Sh 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 5a 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 10 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 IS 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 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.
It is preferred that each protecting sleeve is fastenahle 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 locking 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.
Cl'. 02872252 2014-10-29 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-a-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 he functional to hold the surrounding fractured rock.
As an example only, in normal conditions using a Swellex 0 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, 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.
Hence, according to a broad aspect, the invention provides a rock reinforcement bolt for rock reinforcement of rock faces where problematic rock movements can be expected, the rock reinforcement bolt having: a tubular expandable bolt 6a portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and a support portion for support against a rock face in a region of a mouth of the bore hole, wherein the rock reinforcement bolt has the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site, and wherein at least one protecting sleeve is arranged on an outside of the tubular expandable bolt portion, the protecting sleeve being made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt ability to tackle movements in areas subjected to relative rock movement in the bolt hole, and wherein 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.
According to another broad aspect, the invention relates to a method for installing a rock reinforcement bolt for rock reinforcement of rock faces where problematic rock movements can be expected, the method including: providing a rock reinforcement bolt having: a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and a support portion for support against a rock face in a region of a mouth of the bore hole, arranging at least 6b one protecting sleeve on an outside of the tubular expandable bolt portion the protecting sleeve being made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt ability to tackle movements in areas subjected to relative rock movement in the bolt hole, 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 the bore hole, and subjecting the tubular expandable bolt portion to an inside overpressure for expanding purposes, wherein the rock reinforcement bolt is given the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is being adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site.
According to a further broad aspect, the invention provides protecting sleeve for a rock reinforcement bolt for rock reinforcement of rock faces where problematic rock movements can be expected, the rock reinforcement bolt having:
a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and a support portion for support against a rock face in a region of a mouth of the bore hole, wherein the protecting sleeve is dimensioned to be positioned on an outside of the tubular expandable bolt portion and inside a bolt hole, wherein the protecting sleeve is made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt 6c ability to tackle movements in areas subjected to relative rock movement in the bolt hole, and wherein the protecting sleeve has 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, and wherein the rock reinforcement bolt is given the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site.
BRIEF DESCRIPTION OF DRAWINGS
The invention will now be described in greater detail with reference to the annexed drawings, wherein:
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
Variants, examples and preferred embodiments of the invention are described hereinbelow. 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 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 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 well 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 3D case no additional locking element is necessary at position 17 on the inside of the protecting sleeve 5.
Fig. 9 shows an example where two protecting sleeves 5a and Sh 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 5a 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 10 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 IS 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 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)
1. A rock reinforcement bolt for rock reinforcement of rock faces where problematic rock movements can be expected, the rock reinforcement bolt having:
- a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, - a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and - a support portion for support against a rock face in a region of a mouth of the bore hole, wherein the rock reinforcement bolt has the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site, and wherein at least one protecting sleeve is arranged on an outside of the tubular expandable bolt portion, the protecting sleeve being made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt ability to tackle movements in areas subjected to relative rock movement in the bolt hole, and wherein 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.
- a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, - a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and - a support portion for support against a rock face in a region of a mouth of the bore hole, wherein the rock reinforcement bolt has the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site, and wherein at least one protecting sleeve is arranged on an outside of the tubular expandable bolt portion, the protecting sleeve being made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt ability to tackle movements in areas subjected to relative rock movement in the bolt hole, and wherein 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.
2. The bolt according to claim 1, wherein 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 locking band, a locking tape, an adhesive medium being arranged so as to engage the outside of the tubular expandable belt portion.
3. The bolt according to claim 1 or 2, wherein the material of the protecting sleeve is any one from the group consisting of:
metal, ceramic material, and synthetic material.
metal, ceramic material, and synthetic material.
4. The bolt according to claim 1 or 2, wherein the material is high resistance steel.
5. The bolt according to any one of claims 1 to 4, wherein protecting sleeve length is related to a width of an expected rock movement zone.
6. The bolt according to any one of claims 1 to 5, wherein more than one protecting sleeve are positioned adjacent to each other on the tubular expandable bolt portion.
7. The bolt according to any one of claims 1 to 6, wherein at least one protecting sleeve 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 for rock reinforcement of rock faces where problematic rock movements can be expected, the method including:
providing a rock reinforcement bolt having: a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and a support portion for support against a rock face in a region of a mouth of the bore hole, - arranging at least one protecting sleeve on an outside of the tubular expandable bolt portion the protecting sleeve being made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt ability to tackle movements in areas subjected to relative rock movement in the bolt hole, - 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 the bore hole, and subjecting the tubular expandable bolt portion to an inside overpressure for expanding purposes, wherein the rock reinforcement bolt is given the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is being adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site.
providing a rock reinforcement bolt having: a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and a support portion for support against a rock face in a region of a mouth of the bore hole, - arranging at least one protecting sleeve on an outside of the tubular expandable bolt portion the protecting sleeve being made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt ability to tackle movements in areas subjected to relative rock movement in the bolt hole, - 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 the bore hole, and subjecting the tubular expandable bolt portion to an inside overpressure for expanding purposes, wherein the rock reinforcement bolt is given the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is being adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site.
9. The method according to claim 8, further including the step of fastening each protecting sleeve 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 locking band, a locking tape, an adhesive medium so as to engage the outside of the tubular expandable bolt portion.
a locking ring, a locking clip, a locking 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 of dimensioning protecting sleeve length so as to relate to a width of an expected rock movement zone.
11. The method according to claim 8, 9 or 10, further including the step of positioning more than one protecting sleeve adjacent to each other on the tubular expandable bolt portion.
12. The method according to any one of claims 8 to 11, further including the step of positioning at least one protecting sleeve 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.
13. A protecting sleeve for a rock reinforcement bolt for rock reinforcement of rock faces where problematic rock movements can be expected, the rock reinforcement bolt having:
- a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, - a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and a support portion for support against a rock face in a region of a mouth of the bore hole, wherein the protecting sleeve is dimensioned to be positioned on an outside of the tubular expandable bolt portion and inside a bolt hole, wherein the protecting sleeve is made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt ability to tackle movements in areas subjected to relative rock movement in the bolt hole, wherein the protecting sleeve has 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, and wherein the rock reinforcement bolt is given the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site.
- a tubular expandable bolt portion with a closed cross section for expansion inside a bore hole, the tubular expandable bolt portion having a longitudinal extension, - a connecting portion for the connection of a pressure source to an inside of the tubular expandable bolt portion, and a support portion for support against a rock face in a region of a mouth of the bore hole, wherein the protecting sleeve is dimensioned to be positioned on an outside of the tubular expandable bolt portion and inside a bolt hole, wherein the protecting sleeve is made of a resistant material being high strength steel having properties of resisting movements of rock portions in order to increase bolt energy absorption capabilities and bolt ability to tackle movements in areas subjected to relative rock movement in the bolt hole, wherein the protecting sleeve has 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, and wherein the rock reinforcement bolt is given the ability to withstand harmful rock movements with maintained integrity and functionality to hold surrounding rock and is adaptable for the energy absorbance location and/or capacity of the rock bolt to match rock mass conditions at a particular site.
14. The sleeve according to claim 13, wherein the 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 locking band, a locking tape, an adhesive medium for co-operation with the sleeve.
15. The sleeve according to claim 13 or 14, wherein the sleeve is made from a material from the group consisting of: metal, ceramic material, and synthetic material.
16. The sleeve according to claim 13 or 14, wherein the material is high resistance steel.
17. The sleeve according to any one of claims 13 to 16, wherein protecting sleeve length is related to a width of an expected rock movement zone.
18. The sleeve according to any one of claims 13 to 17, wherein the sleeve 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.
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 |
|---|---|
| CA2872252A1 CA2872252A1 (en) | 2013-11-28 |
| CA2872252C true CA2872252C (en) | 2019-06-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2872252A Active CA2872252C (en) | 2012-05-22 | 2012-05-22 | Rock bolt and method of installing a rock bolt |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA2872252C (en) |
| SE (1) | SE540189C2 (en) |
| WO (1) | WO2013173901A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| MX350675B (en) * | 2013-07-12 | 2017-09-12 | Minova Int Ltd | Yieldable rock anchor. |
| RS60450B1 (en) | 2014-09-03 | 2020-07-31 | Rhizen Pharmaceuticals Sa | Method of treatment and compositions comprising a dual pi3k delta-gamma kinase inhibitor and a corticosteroid |
| US20180171800A1 (en) * | 2015-07-10 | 2018-06-21 | Epiroc Canada Inc. | Shear and tensile reinforcement for inflatable bolt |
| CZ2016244A3 (en) | 2016-04-28 | 2017-06-28 | Dsi Underground Ip Holdings Luxembourg Sarl | An expandable rock bolt with a clamping indicator |
| CN111965254A (en) * | 2019-11-05 | 2020-11-20 | 中国葛洲坝集团第二工程有限公司 | Nondestructive testing method for long exposed anchor rod |
| CN111911191A (en) * | 2020-07-15 | 2020-11-10 | 中国矿业大学 | Control method for over-sliming loose roof roadway |
| AU2021221472A1 (en) * | 2021-08-24 | 2023-03-16 | Fci Holdings Delaware, Inc. | Dynamic rockbolt |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE427764B (en) * | 1979-03-09 | 1983-05-02 | Atlas Copco Ab | MOUNTAIN CULTURAL PROCEDURES REALLY RUCH MOUNTED MOUNTAIN |
| SE8106165L (en) * | 1981-10-19 | 1983-04-20 | Atlas Copco Ab | PROCEDURE FOR MOUNTAIN AND MOUNTAIN |
| WO2004016909A1 (en) * | 2002-08-19 | 2004-02-26 | John Paul Mckelvey | 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 |
-
2012
- 2012-05-22 CA CA2872252A patent/CA2872252C/en active Active
- 2012-05-22 WO PCT/CA2012/050338 patent/WO2013173901A1/en active Application Filing
- 2012-05-22 SE SE1451381A patent/SE540189C2/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| CA2872252A1 (en) | 2013-11-28 |
| WO2013173901A1 (en) | 2013-11-28 |
| SE540189C2 (en) | 2018-04-24 |
| SE1451381A1 (en) | 2014-11-18 |
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