CA1066540A - Dowel device for grouting in a drillhole - Google Patents
Dowel device for grouting in a drillholeInfo
- Publication number
- CA1066540A CA1066540A CA284,217A CA284217A CA1066540A CA 1066540 A CA1066540 A CA 1066540A CA 284217 A CA284217 A CA 284217A CA 1066540 A CA1066540 A CA 1066540A
- Authority
- CA
- Canada
- Prior art keywords
- dowel
- segments
- drillhole
- wedge member
- tensile load
- 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.)
- Expired
Links
- 229920005989 resin Polymers 0.000 claims abstract description 13
- 239000011347 resin Substances 0.000 claims abstract description 13
- 238000000034 method Methods 0.000 claims abstract description 12
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 claims description 18
- 239000011440 grout Substances 0.000 claims description 17
- 238000003780 insertion Methods 0.000 claims description 9
- 230000037431 insertion Effects 0.000 claims description 9
- 239000011435 rock Substances 0.000 claims description 7
- ZOMBKNNSYQHRCA-UHFFFAOYSA-J calcium sulfate hemihydrate Chemical compound O.[Ca+2].[Ca+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O ZOMBKNNSYQHRCA-UHFFFAOYSA-J 0.000 claims description 2
- 239000011505 plaster Substances 0.000 claims description 2
- 229920001187 thermosetting polymer Polymers 0.000 claims description 2
- 239000003365 glass fiber Substances 0.000 claims 3
- 230000015572 biosynthetic process Effects 0.000 claims 2
- 239000011398 Portland cement Substances 0.000 claims 1
- 239000002775 capsule Substances 0.000 description 4
- 238000003776 cleavage reaction Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000007017 scission Effects 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000011152 fibreglass Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910001369 Brass Inorganic materials 0.000 description 1
- 101100346656 Drosophila melanogaster strat gene Proteins 0.000 description 1
- 101100421299 Schizosaccharomyces pombe (strain 972 / ATCC 24843) set7 gene Proteins 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- -1 irsn Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 239000007779 soft material Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000012815 thermoplastic material Substances 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- 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
- F16B13/14—Non-metallic plugs or sleeves; Use of liquid, loose solid or kneadable material therefor
- F16B13/141—Fixing plugs in holes by the use of settable material
- F16B13/143—Fixing plugs in holes by the use of settable material using frangible cartridges or capsules containing the setting components
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
- E21D20/025—Grouting with organic components, e.g. resin
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- General Engineering & Computer Science (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Mechanical Engineering (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Joining Of Building Structures In Genera (AREA)
- Piles And Underground Anchors (AREA)
- Crushing And Pulverization Processes (AREA)
- Farming Of Fish And Shellfish (AREA)
- Dowels (AREA)
Abstract
ABSTRACT
A dowel device for resin grouting, comprising a dowel with a wedge member located in an opening formed in the in-sertion end whereby an end portion is radially expanded and flared outwardly. The invention also includes a method of reinforcing a hard medium and a method of providing an anchorage in a hard medium.
A dowel device for resin grouting, comprising a dowel with a wedge member located in an opening formed in the in-sertion end whereby an end portion is radially expanded and flared outwardly. The invention also includes a method of reinforcing a hard medium and a method of providing an anchorage in a hard medium.
Description
~lti6540 This invention relates to an improved dowel device for g~outing in a drillhole in hard material to provide reinforcement or anrhorage means.
ThP invention also includes a method oi reinforcing a hard ~edium> a method of providing an anchosage in a hard medium, and a hard medium wherein the said dowel devlce is grouted in a drillhole in said medium.
The praotlce of grouting dowels such as reinforcing dowels or anchor bolts in hard medium such as, for example, hard rock is well establi~hed and has been described in British Patent Specificatlons Nos. 953,056 and 1,408,366. In general the method consists in drilling into the medium a hole oversize with respect to the dowel and inserting the dowel wlth a surrounding layer of hardening grouting composition into the drillhDle so tha~, on hardening of the grouting composition~ the dowel is bonded to the drillhole wall. The dowel may terminate w~thin the drillhole or i~ nay extend beyond the mouth of the drillhole and be provided with fixing means for the attachment of other elemen~s or holding a compression plate agains~
the medium at the mouth of the drillhol~. The dowel is preferably fo~med with a flared-out conical portion at its insertion end, which portion acts ;~
as a wedge on the grout material when the dowel is tensioned and thereby ` ;~
improves the holding power of the grout~ ;
- 20 It is an object of this inve~tion to provide an improved flared end dowel device for grouting in a drillhole which can be quickly and simply made from plain dowel stockD
In accordance with the invention a dowel device for grouting in a drillhole comprises a dowel having a wedge member located in an opening -formed in the ins~ertion end of the dowel whereby an end portion of the do~el . ' -~, .
~LO~S~
is radially expanded and flared outwardly.
When the dowel is grouted into the drillhole with a set grouting composition and is tensioned~ either by an end load applied to the dowel end at the mouth of the drillhole or by deformation of the ad~acent r~c'~, the grout adjacent to the flared~end portion of the dowel ls compressed - and its holding power is thereby increased.
The dowel is conveniently split in one or more planes of cleavage extending from the insertion end of the dowel and the wedge member is inserted into the cleavage slit so as to spread the end ~egments. In the preferred form of dowel the end portlon is split along a medial plane and a ; wedge member is placed in the cleavage slit to hold the end segments apart.
The wedge ~ember is preferably disposed in the cleavage slit so as to engage the end segments at a position spaced from the dowel end~ leaving a surface portion of at least one segment bet~een the said position of `
engagement and the dowel end free to fle~ inwardly under ex~ernal pressure `~
on the dowel. This disposition of the wedge member gives a most important practical advantage when the dowel is grouted in rock which undergoes plastic deformation after the grout has set7 With a conventional dowel flared at its lnsertion end the tensile load will progressively increase until the dowel breaks whereas wi~h dowels having the aforedescribed flexible end seg~ent the tensile load wlll be partially released at a characteristic yield pressure and ~he dowel continues to support the -grouting material. Several successive cycles of lsad increase and partial ~- -release can occur so that the reinforcing action of the dowel is maintained ' 25 throu hJuC substsDtial s~vessent of the surrounding rock strat~
'1 :
. ~
~.
. . .. . . .. . .
~65~0 A convenient form of wedge member is a generally flat, rigid plate with its two main faces parallel ~r convergent in the direction of i~sertion into ehe dowel end. Advantageously the leading edge of th~ wedge element is formed as a chisel edge whi~h facilitates its insertion into the dowel end If the dowels are made of wood or plasti~s ~aterial) a metal chisel edged wedge element, for example a steel element3 may àdvantageously be driven lnto a plain dowel end eo split and flare the end, and locate the wedge element iD one rapid operation.
The wedge member preferably extends outside the side surf~ce of the dowel so that the projecting portion assists mixing of the grouting composition when the dowel device is rotated in the drillhole. It is also preferred that, the said projecting side portion of the wedge element is provided with one or more outting ëdges whereby the capsules of encapsulated grout components may be ruptured. The wed~e element may be disposed symmetrically or eccentrically with respect to the longltudinal axis of ~he dowel and~ when the dowel is used in a drillhole in soft material~ an eccentric wedge element may advantageously be effective ~o score a groove in the drillhole wall and thereby provide a key for the grout. The dowel may be made from any constructional material which is sufficien~ly strong to reinforce grouting material and is sufficiently flexible to permit its end to b~ 1ared-out and held in the flared~out pOSitiOn by a wedgeO Thus metals such as irsn, ccpper and aluminium and allDys such as steel, brass and aluminium alloys are suitable. ~ood and hard plastics naterials are also suitable. An especially useful dowel may be made from resin bonded Z5 glasc fibre aDd preferably the glass Eibre Ls proYided as Ei1aments extending ~`
~:, ~ 4 6~54~1 ;
parallel to the dowel axis whereby splitting of the dowel end along an axial plane is facilitated.
Where the aforedescribed load release property is desirable the dowsl preferably has a generally plain cylindrical surface bue otherwise the cylindrical surface ~ay be uneven and be provided~ for example with projections, grooves or threads to enlarge its surface area and improve - the binding to the grout.
The invention also includes a method of reinforcing a hard medium such as rock stra~a, or providing an anchorage in said medium, in which method a dowel device as described above, having its insertion end expanded and flared-out by means of a wedge member located in said end, is inserted into an oversize drillhole in the said medium with said insertion end adjacent to the blind end of the drillhole and a hardening grout material is disposed -in ~he space between the dowel and the drillhole wall wherebyg when the grout material h~rdens, the dowel is bonded to the drillhole wall7 me grouting material may~ for example comprise portland cementJ calcium sulphate hemihydrate plaster or a thermosetting resin. Two-component encapsulated rapid h2rdening resins are especially conv2nient since the components may be dispersed and mixed by a wedge element which pro~ects beyond the side surface of the dowel.
In order to illustrate the $nvent$on further, a preferred dowel device is hereinafter described, by way of example only, with referencè to the - accompanying drawings wherein Fig. 1 shows diagramatically in longitudinal Medial section a dowel device ready or insertion into a drillhole in a rock mass; ~ -' ' ' ~06~iS~0 Fi8. 2 shows diagram~atically a longitudinal medial section of the do~el device of Fig. 1 in a plane penpemdicular to the section of Fig. 1 after the device has been inserted in the drillholeO
me dowel device consists of a generally cylindrical dowel 10 which is split along a medial plane eo provide a bifurcate portion 11 at the insertion end having end segments 12 and 13. The segments 12 and 13 are separated by a wedge element 14 which flexes the seg~ents outwardly so that the end portion 11 flares out from the right cylindrical surface of the remainder of the dowel lO.
me wedge element 14 is a rigid flat rectangular plate with generally parallel transverse main faces 15 and 16 which are fined to converge at a chisel edge 17. The end faces 18 and 19 converge with the main faces 15 and 16 at sharp rectangular cutting edges. The wedge element 14 engages the segments 12 and 13 at positions ~0 and 21 respectively and the segment portions intermediate these positions and the free segment ends are free to flex inwardly.
To grout the dowel deviceg capsules of two-component resin are inserted into a drillhole 22 drilled oversize with respect to the dowel device in rock mass 230 Each capsule consists of an outer container 24 containing hardenable resin 25 and an lnner container 26, located entirely within the rontainer 24 and containing hardening catalyst 27 for the resin 25. BGth contalners are made of thin easily rupturable thermoplastic material.
The dowel device is then simultaneously rotated and inserted into the drillhole 22~ whereupon the capsule~ are engaged by the dowel segments 12 and 13 and the rectangular cutting edges of the wedge element 14. The . .
10665~
thermoplastics containers are ruptured and thP contents are mixed and flow into the space between the dowel lC and the wall of r~he drillhole 22 where the resin subsequently hardens~
When a tensile load is placed on the dowel the resin between the S flared-end portion 11 and the drillhole wall i5 compressed and its holding power enhanced. ~hen the load is increased beyond a critical Yalue, the tension i3 abruptly partially released probably due to inward flexing of the `
- ends of the segments 12 and 13. Ihe tension can then be increased again to the critical value.
In a specific exam?le of dowel device the dowel was a rod 80 cm long x ~ ?
17 mm diameter made from axially oriented fibre glass filamenes bonded by thermosettlng resin. me wet,~,~e element was a generaliy rectangular fibreglass plate 32 mm x 15 mm x 4 mm th~ck located transversely in the split inse~tion ~`~ end of the dowel with its chisel edge 17 at a depth of 3.3 cm from the dowel end, the dowel end se,gments being spread to an overall width of 32 mm, . . .
' 'The dowel was groueed in a 30 cm x 34 mm diameter drillhole in a roc~ mass .
- s ~ .
with a polyester resin grout (which was initially encapsulated) and ~;
subjected to an axial pull. The load on the dowel was progressi~ely `~ ~-increased up to 7 tons whereupon the flared dowel segments yielded and released the load to about 2 tons. The load on the dowel then increased ;
again to the yield point at about 7 tons and was again released. me cycle of load increase and release was repeated and the cycle continued substantially in the same pattern whilst the dowel was withdr,a~n 10 cm ` along the drillhole. `
., :
;' ' .`' ,'' - ~.
';'`~ ' :' ,- '., 7 ~ ~
.,', ' '
ThP invention also includes a method oi reinforcing a hard ~edium> a method of providing an anchosage in a hard medium, and a hard medium wherein the said dowel devlce is grouted in a drillhole in said medium.
The praotlce of grouting dowels such as reinforcing dowels or anchor bolts in hard medium such as, for example, hard rock is well establi~hed and has been described in British Patent Specificatlons Nos. 953,056 and 1,408,366. In general the method consists in drilling into the medium a hole oversize with respect to the dowel and inserting the dowel wlth a surrounding layer of hardening grouting composition into the drillhDle so tha~, on hardening of the grouting composition~ the dowel is bonded to the drillhole wall. The dowel may terminate w~thin the drillhole or i~ nay extend beyond the mouth of the drillhole and be provided with fixing means for the attachment of other elemen~s or holding a compression plate agains~
the medium at the mouth of the drillhol~. The dowel is preferably fo~med with a flared-out conical portion at its insertion end, which portion acts ;~
as a wedge on the grout material when the dowel is tensioned and thereby ` ;~
improves the holding power of the grout~ ;
- 20 It is an object of this inve~tion to provide an improved flared end dowel device for grouting in a drillhole which can be quickly and simply made from plain dowel stockD
In accordance with the invention a dowel device for grouting in a drillhole comprises a dowel having a wedge member located in an opening -formed in the ins~ertion end of the dowel whereby an end portion of the do~el . ' -~, .
~LO~S~
is radially expanded and flared outwardly.
When the dowel is grouted into the drillhole with a set grouting composition and is tensioned~ either by an end load applied to the dowel end at the mouth of the drillhole or by deformation of the ad~acent r~c'~, the grout adjacent to the flared~end portion of the dowel ls compressed - and its holding power is thereby increased.
The dowel is conveniently split in one or more planes of cleavage extending from the insertion end of the dowel and the wedge member is inserted into the cleavage slit so as to spread the end ~egments. In the preferred form of dowel the end portlon is split along a medial plane and a ; wedge member is placed in the cleavage slit to hold the end segments apart.
The wedge ~ember is preferably disposed in the cleavage slit so as to engage the end segments at a position spaced from the dowel end~ leaving a surface portion of at least one segment bet~een the said position of `
engagement and the dowel end free to fle~ inwardly under ex~ernal pressure `~
on the dowel. This disposition of the wedge member gives a most important practical advantage when the dowel is grouted in rock which undergoes plastic deformation after the grout has set7 With a conventional dowel flared at its lnsertion end the tensile load will progressively increase until the dowel breaks whereas wi~h dowels having the aforedescribed flexible end seg~ent the tensile load wlll be partially released at a characteristic yield pressure and ~he dowel continues to support the -grouting material. Several successive cycles of lsad increase and partial ~- -release can occur so that the reinforcing action of the dowel is maintained ' 25 throu hJuC substsDtial s~vessent of the surrounding rock strat~
'1 :
. ~
~.
. . .. . . .. . .
~65~0 A convenient form of wedge member is a generally flat, rigid plate with its two main faces parallel ~r convergent in the direction of i~sertion into ehe dowel end. Advantageously the leading edge of th~ wedge element is formed as a chisel edge whi~h facilitates its insertion into the dowel end If the dowels are made of wood or plasti~s ~aterial) a metal chisel edged wedge element, for example a steel element3 may àdvantageously be driven lnto a plain dowel end eo split and flare the end, and locate the wedge element iD one rapid operation.
The wedge member preferably extends outside the side surf~ce of the dowel so that the projecting portion assists mixing of the grouting composition when the dowel device is rotated in the drillhole. It is also preferred that, the said projecting side portion of the wedge element is provided with one or more outting ëdges whereby the capsules of encapsulated grout components may be ruptured. The wed~e element may be disposed symmetrically or eccentrically with respect to the longltudinal axis of ~he dowel and~ when the dowel is used in a drillhole in soft material~ an eccentric wedge element may advantageously be effective ~o score a groove in the drillhole wall and thereby provide a key for the grout. The dowel may be made from any constructional material which is sufficien~ly strong to reinforce grouting material and is sufficiently flexible to permit its end to b~ 1ared-out and held in the flared~out pOSitiOn by a wedgeO Thus metals such as irsn, ccpper and aluminium and allDys such as steel, brass and aluminium alloys are suitable. ~ood and hard plastics naterials are also suitable. An especially useful dowel may be made from resin bonded Z5 glasc fibre aDd preferably the glass Eibre Ls proYided as Ei1aments extending ~`
~:, ~ 4 6~54~1 ;
parallel to the dowel axis whereby splitting of the dowel end along an axial plane is facilitated.
Where the aforedescribed load release property is desirable the dowsl preferably has a generally plain cylindrical surface bue otherwise the cylindrical surface ~ay be uneven and be provided~ for example with projections, grooves or threads to enlarge its surface area and improve - the binding to the grout.
The invention also includes a method of reinforcing a hard medium such as rock stra~a, or providing an anchorage in said medium, in which method a dowel device as described above, having its insertion end expanded and flared-out by means of a wedge member located in said end, is inserted into an oversize drillhole in the said medium with said insertion end adjacent to the blind end of the drillhole and a hardening grout material is disposed -in ~he space between the dowel and the drillhole wall wherebyg when the grout material h~rdens, the dowel is bonded to the drillhole wall7 me grouting material may~ for example comprise portland cementJ calcium sulphate hemihydrate plaster or a thermosetting resin. Two-component encapsulated rapid h2rdening resins are especially conv2nient since the components may be dispersed and mixed by a wedge element which pro~ects beyond the side surface of the dowel.
In order to illustrate the $nvent$on further, a preferred dowel device is hereinafter described, by way of example only, with referencè to the - accompanying drawings wherein Fig. 1 shows diagramatically in longitudinal Medial section a dowel device ready or insertion into a drillhole in a rock mass; ~ -' ' ' ~06~iS~0 Fi8. 2 shows diagram~atically a longitudinal medial section of the do~el device of Fig. 1 in a plane penpemdicular to the section of Fig. 1 after the device has been inserted in the drillholeO
me dowel device consists of a generally cylindrical dowel 10 which is split along a medial plane eo provide a bifurcate portion 11 at the insertion end having end segments 12 and 13. The segments 12 and 13 are separated by a wedge element 14 which flexes the seg~ents outwardly so that the end portion 11 flares out from the right cylindrical surface of the remainder of the dowel lO.
me wedge element 14 is a rigid flat rectangular plate with generally parallel transverse main faces 15 and 16 which are fined to converge at a chisel edge 17. The end faces 18 and 19 converge with the main faces 15 and 16 at sharp rectangular cutting edges. The wedge element 14 engages the segments 12 and 13 at positions ~0 and 21 respectively and the segment portions intermediate these positions and the free segment ends are free to flex inwardly.
To grout the dowel deviceg capsules of two-component resin are inserted into a drillhole 22 drilled oversize with respect to the dowel device in rock mass 230 Each capsule consists of an outer container 24 containing hardenable resin 25 and an lnner container 26, located entirely within the rontainer 24 and containing hardening catalyst 27 for the resin 25. BGth contalners are made of thin easily rupturable thermoplastic material.
The dowel device is then simultaneously rotated and inserted into the drillhole 22~ whereupon the capsule~ are engaged by the dowel segments 12 and 13 and the rectangular cutting edges of the wedge element 14. The . .
10665~
thermoplastics containers are ruptured and thP contents are mixed and flow into the space between the dowel lC and the wall of r~he drillhole 22 where the resin subsequently hardens~
When a tensile load is placed on the dowel the resin between the S flared-end portion 11 and the drillhole wall i5 compressed and its holding power enhanced. ~hen the load is increased beyond a critical Yalue, the tension i3 abruptly partially released probably due to inward flexing of the `
- ends of the segments 12 and 13. Ihe tension can then be increased again to the critical value.
In a specific exam?le of dowel device the dowel was a rod 80 cm long x ~ ?
17 mm diameter made from axially oriented fibre glass filamenes bonded by thermosettlng resin. me wet,~,~e element was a generaliy rectangular fibreglass plate 32 mm x 15 mm x 4 mm th~ck located transversely in the split inse~tion ~`~ end of the dowel with its chisel edge 17 at a depth of 3.3 cm from the dowel end, the dowel end se,gments being spread to an overall width of 32 mm, . . .
' 'The dowel was groueed in a 30 cm x 34 mm diameter drillhole in a roc~ mass .
- s ~ .
with a polyester resin grout (which was initially encapsulated) and ~;
subjected to an axial pull. The load on the dowel was progressi~ely `~ ~-increased up to 7 tons whereupon the flared dowel segments yielded and released the load to about 2 tons. The load on the dowel then increased ;
again to the yield point at about 7 tons and was again released. me cycle of load increase and release was repeated and the cycle continued substantially in the same pattern whilst the dowel was withdr,a~n 10 cm ` along the drillhole. `
., :
;' ' .`' ,'' - ~.
';'`~ ' :' ,- '., 7 ~ ~
.,', ' '
Claims (13)
1. A dowel device insertable in a drillhole for grouting therein, said device comprising an elongate dowel element made of material capable of flexing under load, said dowel element having an end portion split into two substantially straight end segments, and a wedge member disposed in the opening between said segments in engagement with the inner faces of said segments to flare said segments radially, said wedge member being shaped so that the place of engagement with at least one of said segments is at a position spaced suffici-ently from the dowel end that the end portion of said one segment is left free to flex inwardly under a predetermined tensile load on the dowel which is less than the tensile load required to break the dowel whereby the tensile load is partially released.
2. A device as in Claim 1 wherein the wedge element is positioned in said opening so that it does not extend beyond the dowel end.
3. A device as in Claim 1 wherein the wedge member is a generally flat rigid plate engaging the dowel end segments along two opposed corners on opposed faces of said wedge member.
4. A device as in Claim 1 wherein the wedge member is a generally flat, rigid plate with its two main faces parallel or convergent in the direction of insertion into the dowel end.
A device as in Claim 4 wherein the leading stage of the wedge member is formed as a chisel edge which facilitates its insertion into the dowel end.
6. A device as in Claim 1 wherein the wedge member extends outside the side surface of the dowel element.
7. A device as in Claim 1 wherein the dowel element is made from resin bonded glass fibre.
8. A device as in Claim 7 wherein the glass fibre in the dowel is provided as filaments extending parallel to the axis of the dowel element.
9. A method of reinforcing a hard medium comprising inserting a dowel device into an over-size drillhole in said medium, said drill hole having an open outer end and a blind inner end, and said dowel device comprising an elongate dowel element made of material capable of flexing under load having an end portion split into two substantially straight end segments, and further comprising a wedge member disposed in the opening between said segments in engagement with the inner faces of said segments to flare said segments radially, said wedge member being shaped so that the place of engagement with at least one of said segments is at a position spaced sufficiently from the dowel end that the end portion of said one segment is left free to flex inwardly under a predetermined tensile load on the dowel which is less than the tensile load required to break the dowel, the end of said dowel device contaning the wedge member being disposed adjacent the blind end of the drillhole; and disposing a hardening grout material in the space between the dowel element of said dowel device and the drillhole wall whereby, when the grout material hardens, the dowel device is bonded to the drillhole wall.
10. A method as in Claim 9 wherein the grouting material is selected from the group consisting of portland cement, calcium sulphate hemihydrate plaster or thermosetting resin.
11. A method as in Claim 10 wherein the grouting material comprises a two-component encapsulated rapid hardening resin.
12. A method of providing an anchorage in a hard medium comprising: inserting a dowel device into an oversize drillhole in said medium, said drillhole having an open outer end and a blind inner end, and said dowel device comprising an elongated dowel element made of material capable of flexing under load having an end portion split into two substantially straight end segments, and further comprising a wedge member disposed in the opening between said segments in engagement with the inner faces of said segments to flare said segments radially, said wedge member being shaped so that the place of engagement with at least one of said segments is at a position spaced sufficiently from the dowel end that the end portion of said one segment is left free to flex inwardly under a pre-determined tensile load on the dowel which is less than the tensile load required to break the dowel, the end of said dowel device containing the wedge member being disposed adjacent to the blind end of the drillhole; and disposing a hardening grout material in the space between the dowel element of said dowel device and the drillhole wall whereby, when the grout material hardens, the dowel device is bonded to the drillhole wall and whereby the tensile load on the dowel can be released by flexing of said dowel segment.
13. A method of reinforcing a hard rock formation comprising: inserting a dowel device into an oversize drill-hole in the formation, said drillhole having an open outer end and a blind inner end, said dowel device having an elongated dowel element one end portion of which has been split into two substantially straight end segments and a wedge member inserted into the split and flexing the end segments radially outwardly, the dowel element being constructed of resin-bonded glass fibre extending parallel to the axis of the dowel element and the wedge member being shaped so that the place of engagement with at least one of said segments is at a position spaced sufficiently from the dowel end that the end portion of said one segment is left free to flex inwardly under a predetermined tensile load on the dowel which is less than the tensile load to break the dowel, and the wedge member being a flat rigid plate wholly disposed between the segments and having lateral edges which extend outside the surface of the dowel element, the wedge-end of the dowel device being disposed adjacent the blind end of the drillhole;
and then bonding the dowel device to the wall of the drill-hole by disposing a hardening grout material in the space between the dowel element and the wall of the drillhole and by rotating the dowel device so as to mix the hardening grout.
and then bonding the dowel device to the wall of the drill-hole by disposing a hardening grout material in the space between the dowel element and the wall of the drillhole and by rotating the dowel device so as to mix the hardening grout.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB33803/76A GB1524469A (en) | 1976-08-13 | 1976-08-13 | Dowel device for grouting in a drillhole |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1066540A true CA1066540A (en) | 1979-11-20 |
Family
ID=10357646
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA284,217A Expired CA1066540A (en) | 1976-08-13 | 1977-08-05 | Dowel device for grouting in a drillhole |
Country Status (8)
| Country | Link |
|---|---|
| AU (1) | AU505413B2 (en) |
| BE (1) | BE857592A (en) |
| CA (1) | CA1066540A (en) |
| DE (1) | DE2734633A1 (en) |
| ES (1) | ES461580A1 (en) |
| FR (1) | FR2361564A1 (en) |
| GB (1) | GB1524469A (en) |
| NO (1) | NO772467L (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3118492A1 (en) * | 1981-05-09 | 1982-12-02 | Bayer Ag, 5090 Leverkusen | FORCE INITIAL ELEMENT FOR FIBER COMPOSITES |
| DE3620972A1 (en) * | 1986-06-23 | 1988-01-14 | Hilti Ag | ANCHORABLE ROD ANCHORABLE BY MEANS OF A CURATIVE RANGE |
Family Cites Families (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2667037A (en) * | 1949-08-24 | 1954-01-26 | Edward M Thomas | Suspension roof support |
| US2697914A (en) * | 1949-10-11 | 1954-12-28 | Joy Mfg Co | Releasable wedge type roof bolt |
| US2725843A (en) * | 1951-06-01 | 1955-12-06 | Francis A E Koski | Sag indicator |
| US2651962A (en) * | 1951-06-25 | 1953-09-15 | John V Hammond | Wedge type bolt or pin |
| FR1100773A (en) * | 1953-05-26 | 1955-09-23 | Gutehoffnungshuette Sterkrade | Biting tooth device for anchors in mine support |
| DE1008234B (en) * | 1954-06-18 | 1957-05-16 | Gutehoffnungshuette Sterkrade | Rock anchor for pit construction in mining |
| FR1128704A (en) * | 1955-07-07 | 1957-01-09 | Forges Et Boulonneries Hermant | Wedge anchor rod and method of making this rod |
| FR1186263A (en) * | 1957-07-31 | 1959-08-19 | Saarbergwerke | Anchor bolt safety wedge |
| CH385140A (en) * | 1959-04-20 | 1964-12-15 | Bergwerksverband Gmbh | Method of fastening anchors in the boreholes receiving them |
| FR1356888A (en) * | 1963-05-24 | 1964-03-27 | Process in particular for supporting the roofs of underground galleries as well as devices for implementing the present process or similar process | |
| FR85195E (en) * | 1964-02-10 | 1965-06-25 | Process in particular for supporting the roofs of underground galleries as well as devices for implementing the present process or similar process | |
| FR87644E (en) * | 1965-04-01 | 1966-04-15 | Forges Et Boulonneries Hermant | Anchoring device |
| GB1195686A (en) * | 1966-10-03 | 1970-06-17 | James Deans Cumming | Improvements in or relating to Friction Grip Fasteners |
| BE795928A (en) * | 1970-04-27 | 1973-06-18 | Celtite Sa | SEALING RODS IMPROVEMENTS |
| GB1408366A (en) * | 1973-06-22 | 1975-10-01 | Ici Ltd | Anchor bolt |
| FR2337812A1 (en) * | 1976-01-08 | 1977-08-05 | Celtite Sa | Mine support anchor bolt - has glass fibre reinforced rod and split collar expanded by wedge against bottom of hole (SW 1.8.77) |
-
1976
- 1976-08-13 GB GB33803/76A patent/GB1524469A/en not_active Expired
-
1977
- 1977-07-12 NO NO772467A patent/NO772467L/en unknown
- 1977-07-14 AU AU27012/77A patent/AU505413B2/en not_active Expired
- 1977-08-01 DE DE19772734633 patent/DE2734633A1/en active Pending
- 1977-08-05 CA CA284,217A patent/CA1066540A/en not_active Expired
- 1977-08-08 BE BE180001A patent/BE857592A/en unknown
- 1977-08-12 FR FR7724931A patent/FR2361564A1/en not_active Withdrawn
- 1977-08-12 ES ES461580A patent/ES461580A1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| NO772467L (en) | 1978-02-14 |
| FR2361564A1 (en) | 1978-03-10 |
| ES461580A1 (en) | 1978-12-01 |
| GB1524469A (en) | 1978-09-13 |
| AU2701277A (en) | 1979-01-18 |
| DE2734633A1 (en) | 1978-02-16 |
| BE857592A (en) | 1978-02-08 |
| AU505413B2 (en) | 1979-11-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1243516A (en) | Method and apparatus for combining resin bonding and mechanical anchoring of a bolt in a rock formation | |
| US4295761A (en) | Post tensionable grouted anchor assembly | |
| US4055051A (en) | Unitary drill bit and roof bolt | |
| US4664561A (en) | Combined resin-mechanical mine roof bolt anchor | |
| US4564315A (en) | Method for anchoring a bolt in a rock-like structure | |
| CA1327466C (en) | Roof bolt system | |
| AU667758B2 (en) | Non-metallic reinforcing rod and method of use in supporting a rock formation | |
| US4611954A (en) | Apparatus and method for mine installations | |
| US4659258A (en) | Dual stage dynamic rock stabilizing fixture and method of anchoring the fixture in rock formations | |
| US4607984A (en) | Apparatus and method for mine application | |
| US4100954A (en) | Dowel or anchoring means | |
| US4386877A (en) | Mine roof bolting | |
| US4193715A (en) | Mine roof support method and apparatus | |
| US4679966A (en) | Roof bolt apparatus with expansion shell and coupling | |
| US4820095A (en) | Anchor device for securing rock bolts | |
| US6390735B1 (en) | Apparatus and method for a yieldable tendon mine support | |
| US4122681A (en) | Mine roof support assembly | |
| US4167359A (en) | Dowel device for grouting in a drillhole | |
| CN1305065A (en) | Anchor rod fixed by organic and/or inorganic mortar | |
| CA1066540A (en) | Dowel device for grouting in a drillhole | |
| US4192631A (en) | Mine roof support method and apparatus | |
| US4664573A (en) | Mine wall support anchor | |
| RU2053336C1 (en) | Fastening device | |
| CA1172476A (en) | Removable tension member for a grout anchor | |
| GB2263958A (en) | "anchoring of fixing elements by settable material" |