CN215518751U - Free-section-free micro-pile type large-diameter slow-bonding prestressed uplift anchor rod - Google Patents

Abstract

The utility model provides a free-section-free miniature pile type large-diameter slow-bonding prestressed uplift anchor rod which comprises a rib body, wherein the rib body is composed of a plurality of slow-bonding steel stranded wires, one to two circles of water swelling water stop strips wound by one circle are arranged on the outer side of each slow-bonding steel stranded wire on the lower portion of a reinforced structure, an anchorage device and an anchor backing plate are arranged at the tensioning end of the rib body, an anchoring bearing structure is arranged at the anchoring end of the rib body, the anchoring bearing structure comprises a construction frame vertical rib, a spiral hoop rib and a bearing body, the anchoring end is positioned at the bottom of a drill hole, and the drill hole is completely filled with grouting slurry. The free-section-free micro-pile type large-diameter slow-bonding prestress anti-pulling anchor rod is high in overall anti-pulling capacity, high in safety factor, excellent in anti-corrosion performance and good in durability.

Description

Free-section-free micro-pile type large-diameter slow-bonding prestressed uplift anchor rod

Technical Field

The utility model belongs to the technical field of civil engineering prestressed anchor rods, and particularly relates to a miniature pile type large-diameter slow-bonding prestressed uplift anchor rod without a free section, in particular to a miniature pile type large-diameter slow-bonding prestressed uplift anchor rod without a free section with excellent durability.

Background

The diameter of the existing prestressed anchor rod is generally below 200mm, the diameter of the anchor rod is small, the pulling resistance is small, the number is large inevitably to meet the pulling resistance design requirement, if the diameter of the anchor rod is increased, the pulling resistance of a single anchor rod can be increased naturally, the number of the anchor rods can be reduced, the manufacturing cost can be reduced, and the construction period of the anchor rod can be shortened; in addition, the free section of the existing anchor rod is required to be arranged for tensioning, but the corrosion prevention construction quality of the free section is difficult to guarantee.

The prestressed anchor rod can be divided into a tension type anchor rod and a pressure type anchor rod according to whether the prestressed steel strand is bonded with the grouting slurry or not. The durability of the tension type anchor rod with the bonded steel strand has four weak links, firstly, slurry in an anchoring section is pulled to crack in the process of prestress tensioning and later stress, the steel strand is corroded, if a plastic corrugated pipe is sleeved outside the steel strand, the steel strand can be protected, but because the aperture of the anchor rod is small, the slurry amount outside the corrugated pipe is small, the pulling resistance of the anchor rod is influenced, the construction is quite troublesome, and the quality is difficult to guarantee; secondly, the protection of the free section is difficult to treat, and the steel strand is easy to rust; thirdly, if the clamping piece of the anchorage device at the tensioning end is not well anchored, the clamping piece in a high stress state is easy to rust, so that the prestress is completely failed; fourthly, the steel strand is formed by winding a plurality of high-strength steel wires, underground water can enter the steel strand from the cracked grouting slurry, and reaches the clamping piece of the anchorage device along the gap between the steel strands to cause the clamping piece to rust in a high-stress state, so that the anchor rod is completely ineffective;

the pressure type anchor rod adopting the unbonded steel stranded wire has the advantages that the uplift bearing capacity and the corrosion resistance are greatly superior to those of a tension type anchor rod, but three weak links exist, firstly, the anchor sealing is not well done, so that external rainwater permeates into the clamping piece of the anchorage device, and the clamping piece is rusted, and the prestressed anchor rod fails; secondly, because the test load of the acceptance test of the anchor rod is twice of the characteristic value of the uplift resistance of the anchor rod, because the drilled hole of the anchor rod is small (the diameter of the drilled hole of the existing prestressed anchor rod is generally below 200 mm), the stress of cement slurry at the bearing body at the tail end of the anchoring section is very large, and the situation that the anchor rod is not crushed during the maximum test load is difficult to ensure; thirdly, the space between the extrusion sleeve of the bearing body of the anchoring section and the steel strand is difficult to be completely sealed, and underground water can enter the clamping piece along the gap between the steel strands to cause the clamping piece to rust, so that the anchor rod fails. Generally, pressure anchors using unbonded steel strands are more durable than tension anchors.

Although the anti-pulling force and the anti-corrosion performance of the pressure type prestressed anchor rod adopting the unbonded steel strand are greatly superior to those of the tension type anchor rod adopting the bonded steel strand, the drilling diameter of the prestressed anchor rod applied at present is generally below 200mm, the local pressure bearing of the bearing body at the end part of the prestressed anchor rod is difficult to meet the tension requirement of the anchor rod during the acceptance test, the prestressed anchor rod cannot be widely applied, meanwhile, the pressure type prestressed anchor rod adopting the unbonded steel strand is completely stressed by a tension end anchorage device and an anchoring section bearing body, once the two are in the middle, one end of the prestressed anchor rod is corroded, and the anchor rod can fail.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problems, and provides a miniature pile type large-diameter slow-bonding prestressed uplift anchor rod which can combine the advantages of a miniature pile and an unbonded prestressed pressure anchor rod, can overcome the defects of the miniature pile type large-diameter slow-bonding prestressed uplift anchor rod and has excellent corrosion resistance.

In order to achieve the purpose, the utility model provides a free-section-free miniature pile type large-diameter slow-bonding prestressed uplift anchor rod, the overall length of the anchor rod is an anchoring section without a free section, the anchor rod comprises a rib body, the rib body consists of a plurality of slow-bonding steel stranded wires, one to two circles of water swelling water stop strips wound by one circle are arranged on the outer side of each slow-bonding steel stranded wire at the lower part of a reinforced structure, an anchorage device and an anchor backing plate are arranged at the tensioning end of the rib body, an anchoring bearing structure is arranged at the anchoring end of the rib body, the anchoring bearing structure comprises a construction erection rib, a spiral hoop rib and a bearing body, the anchoring end is positioned at the bottom of a drill hole, and the drill hole is completely filled with grouting slurry.

According to the anchor rod of the utility model, the diameter of the drilled hole is preferably 300mm or more.

According to the anchor rod of the present invention, preferably, one or more anchoring carrier structures are provided in the anchoring section.

According to the bolt of the utility model, preferably the anchor segments are of equal diameter.

According to the anchor rod of the present invention, preferably, at least one enlarged head is provided in the anchoring section.

According to the anchor rod of the utility model, preferably, the enlarged head is cylindrical or spherical.

According to the anchor rod of the present invention, preferably, the rib body is bent into a U shape at the carrier, and the carrier is a U-shaped steel plate.

According to the anchor rod of the utility model, preferably, when the thickness of the reinforced structure is smaller than the prestress transmission length of the slow bonding steel strand, an anchor rod bearing platform is arranged at the lower part of the reinforced structure.

According to the anchor rod of the present invention, preferably, the grouting slurry is cement paste, cement mortar or concrete.

According to the anchor rod of the utility model, the supporting body is preferably composed of a steel plate and a pressing sleeve.

Compared with the prior art, the free-section-free micro-pile type large-diameter slow-bonding prestress anti-pulling anchor rod has the advantages of high overall anti-pulling force, high safety coefficient, excellent corrosion resistance and good durability.

Drawings

Fig. 1 is a schematic structural view of a two-segment prestressed uplift anchor rod provided with a free segment and an anchoring segment in the prior art.

Fig. 2 is a schematic view of a single large-diameter slow-bonding prestressed uplift anchor rod without an enlarged head according to the present invention.

Fig. 3 is a schematic view of a single large-diameter slow-bonding prestressed uplift anchor rod provided with an enlarged head according to the present invention.

Fig. 4 is a schematic view of the composite large-diameter slow-bonding prestressed uplift anchor rod without the enlarged head according to the utility model.

Fig. 5 is a schematic view of a composite large-diameter slow-bonding prestressed uplift anchor rod provided with a plurality of enlarged heads according to the present invention.

Fig. 6 is a schematic view of a large diameter slow bonded prestressed uplift anchor without an anchor cap according to the present invention.

Detailed Description

To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to the accompanying drawings and specific embodiments.

It is to be noted that some conventional technical operation steps, materials and apparatuses are not described in detail in the following examples for the purpose of brevity and clarity, but it is to be understood that the conventional technical operation steps, materials and apparatuses are obvious to those skilled in the art if not specifically stated.

Fig. 1 is a schematic structural diagram of a two-segment prestressed uplift anchor rod provided with an anchoring segment 11 and a free segment 12 in the prior art. The existing two-section type prestressed anchor rod comprises an anchoring section 11 and a free section 12, wherein the free section 12 consists of a prestressed reinforcement body 1, an outer-wrapped isolation sleeve 15 surrounding the reinforcement body 1 and grouting slurry 6. Such two-stage pre-stressed anchors of the prior art are usually arranged in the borehole 5 and the full length of the tunnel is grouted.

As shown in fig. 2, 3, 4, 5 and 6, the present invention is a schematic structural view of various embodiments of a free-segment-free micro-pile large-diameter slow-bonding prestressed uplift anchor rod with excellent durability. The anchor rod can be widely applied to major projects requiring excellent durability of the anchor rod, such as the anti-overturning stability reinforcement of a concrete dam, the anti-floating of a basement bottom plate, the stable anchoring of guy cable piers at two ends of a suspension bridge, the anti-overturning stability anchoring of a foundation of a large tower type starter at a port, the anti-overturning stability anchoring of a large power transmission and transformation line iron tower foundation and the like.

The utility model discloses a miniature pile type large-diameter slow-bonding prestressed uplift anchor rod with excellent durability and no free section, which comprises a rib body 1, wherein the rib body 1 consists of a plurality of slow-bonding steel stranded wires, one to two water swelling water stop strips 14 wound by one circle are arranged on the outer side of each slow-bonding steel stranded wire at the lower part of a reinforced structure 9, and underground water can be prevented from entering a tensioning end anchorage device 2 along the outer side of the wrapping of the slow-bonding steel stranded wire. The stretching end of the rib body 1 is provided with an anchorage device 2 and an anchor backing plate 3, the anchoring end of the rib body 1 is provided with an anchoring bearing structure, the anchoring bearing structure comprises a construction frame vertical rib 8, a spiral stirrup 7 and a bearing body 4 (the bearing body 4 can be an extrusion sleeve and a steel anchor backing plate or a U-shaped iron plate, and can be a single bearing body 4 or a plurality of bearing bodies 4 arranged in sections), the anchoring end is positioned in a drill hole 5, and the drill hole 5 is completely filled with grouting slurry 6 (can be cement paste, cement mortar or concrete).

The water-swellable stop 14 is a commercially available product, and is commercially available to those skilled in the art, and has the properties of self-swelling in water, stopping water by swelling upon absorption of water, and swelling deformation of 2 to 3 times after contact with water, and filling all irregular surfaces, cavities and gaps of the joint with a great contact pressure, completely preventing leakage. Can be a water-swelling putty strip or a water-swelling rubber strip.

Aiming at the characteristic of large test load during the acceptance test of the anchor rod, structural longitudinal steel bars and local pressure-bearing spiral stirrups are arranged in the range of the steel plate of the bearing body at the bottom of the anchoring section so as to improve the local pressure-bearing capacity and protect the grouting slurry at the bearing body from cracking.

When the thickness of the reinforced structure 9 is smaller than the prestress transmission length of the slow-bonding steel strand, the anchor rod bearing platform 10 is arranged at the lower part of the reinforced structure 9, and the measure is taken to ensure that the anchor rod can still continuously play a role and cannot fail in case the anchor device 2 at the tensioning end is corroded to fail, so that the durability of the anchor rod can be greatly improved, and the reinforced structure 9 is more stable.

The diameter of the anchor hole 5 of the anchor rod of the utility model is more than 300mm, and the diameter can be a hole with equal diameter or a single hole or a plurality of holes with local enlarged heads 13 (namely, the hole diameter is increased). The anchor rod provided by the utility model uses a micro pile hole forming method for reference, and adopts a large-diameter hole with the diameter of more than 300mm, so that on one hand, the uplift resistance of the anchor rod can be improved, and meanwhile, the anchor backing plate of the bearing body can be enlarged, so that the local bearing of the bearing body meets the requirement of the maximum test uplift resistance in an anchor rod acceptance test. The prestressed reinforcement body 1 is a steel strand, and is preferably a slow-bonding steel strand. The retarded adhesive steel strand is a general product name in the field, the retarded adhesive steel strand adopted by the tendon body 1 of the prestressed anchor is the existing, and the retarded adhesive steel strand is produced in batches at present in China and can be purchased and obtained through commercial channels. The retarded adhesive steel strand can freely slide in concrete and grout in the tensioning working period, prestressed tensioning locking can be implemented, after the retarded adhesive material is completely cured, the reinforcement body is protected by three layers, the first layer is a high-strength cured layer formed by epoxy resin with the thickness of more than 2mm and filler which is formed after the steel strand is cured outside the steel strand, tightly wraps the steel strand (the compressive strength is more than 50MPa), has excellent corrosion resistance, and is wrapped by a high-density polyethylene ribbed outer sleeve with the thickness of more than 1mm, after the retarded adhesive of the retarded adhesive steel strand is cured, the tensioning end position is completely combined with the concrete of the reinforced structure 9 through the retarded adhesive steel strand of the reinforced structure 9, the whole length of the retarded adhesive steel strand at the anchoring section position is combined with the grout 6 in an anchor rod hole, even if a clamping piece of an anchorage device 2 at the tensioning end rusts and a bearing body 4 of the anchoring section rusts and corrodes during the use process, but because the anchor rod slowly bonds steel strand wires muscle body 1 and the concrete and the grout body complete interlock of supporting construction, the anchor rod also can not become invalid.

At anchor section supporting body 4 department, the slowly-bonded steel strand wires can be bent into the U type, adopt U type steel sheet as the supporting body, this kind of structure can ensure slowly to bond the steel strand wires full length and seal, the durability is better, also can adopt traditional extrusion cover and pressure-bearing steel sheet, slowly bond the steel strand wires muscle body and have three protective barriers, the grout body that can not ftracture that is in the pressurized state firstly, secondly slowly bond the outer polyethylene plastic sheath of steel strand wires, thirdly the delayed coagulation adhesive after the solidification, three protection makes the stock have very superior corrosion resisting property, at present, domestic existing producer can produce and sell slowly and bond prestressed steel strand wires, and there is corresponding slowly bonding steel strand wires industry standard.

The anchor rod can be provided with one or more supporting bodies 4, and the anchor rod can be made into an anchor rod with a single anchoring section or a composite anchor rod with a plurality of anchoring sections. The anchor bore 5 can be provided with one or more enlarged heads 13 at the location of the carrier 4, or without enlarged heads. The supporting body 4 can be arranged in sections to form a composite anchor rod, and the requirements of the uplift resistance are specifically determined according to the geological condition of the soil layer and the design calculation.

Fig. 3 shows an embodiment of a single large diameter slow bonded prestressed uplift anchor provided with an enlarged head 13. The basic construction of the anchor shown in fig. 3 is generally similar to that of the anchor shown in fig. 2, except that at the location of the anchor load bearing structure (including the frame studs 8, the spiral stirrups 7 and the carrier 4) there is also provided an enlarged head 13, which enlarged head 13 can be considered to be a laterally enlarged portion of the borehole 5.

Fig. 4 shows an embodiment of a composite large diameter slow bonded prestressed uplift anchor without the enlarged head 13. The basic construction of the rock bolt shown in fig. 3 is generally similar to that of the rock bolt shown in fig. 2, except that the rock bolt has a plurality of anchor bearing structures (including the construction set bars 8, the spiral stirrups 7 and the carrier 4), as shown there is one anchor bearing structure at the anchor end of the rock bolt, and there are two or more anchor bearing structures between the anchor end and the tensioning end, in the grout filled portion.

Fig. 5 shows an embodiment of a composite large diameter slow bonded prestressed uplift anchor provided with an enlarged head 13. The basic construction of the anchor shown in fig. 3 is generally similar to that of the anchor shown in fig. 4, except that at the location of the anchor load bearing structure (including the frame studs 8, the spiral stirrups 7 and the carrier 4) there is also provided an enlarged head 13, which enlarged head 13 can be considered as a laterally enlarged portion of the borehole 5. That is, the anchor rod in fig. 5 may have two or more laterally protruding enlarged heads 13 and corresponding anchor bearing structures to further enhance its anchoring strength.

As shown in fig. 2 to 5, when the thickness of the reinforced structure 9 is smaller than the prestress transmission length of the slow-bonding steel strand, it is necessary to provide an anchor bearing platform 10 at the lower portion of the reinforced structure 9, i.e., the portion of the reinforced structure 9 formed to protrude downward is the anchor bearing platform 10, so as to ensure that the anchor will not fail in case of failure of the tension end anchor 2.

As shown in fig. 6, when the thickness of the reinforced structure 9 is greater than the prestress transmission length of the slow adhesion steel strand, the anchor platform 10 is not provided, and the lower portion of the reinforced structure 9 does not protrude downward.

Although fig. 4 and 5 only show examples with two enlarged heads 13 and/or two anchor carrying structures, it will be understood by those skilled in the art that the number of enlarged heads 13 and anchor carrying structures may vary and is not limited to only two.

The anchor rod rib body of the utility model adopts the slow bonding prestressed steel strand, the free section method of the traditional anchor rod is cancelled, the free section is not specially arranged in the whole length without a sleeve, the whole length of the anchor rod is the free section before the slow bonding steel strand is tensioned and completely cured, the anchor rod is a pressure type anchor rod at the moment, the established effective prestress is large, the uplift force of the pressure type anchor rod is usually larger or not smaller than that of a tension type anchor rod, the uplift force is mainly provided by a rock body or a soil body with better soil property at the tail end of an anchoring section, the anchor rod is converted from the pressure type into a tension type anchor rod after the slow bonding steel strand is completely cured, but the compression stress borne by the grouting slurry is larger due to the early tensioning, the anchor rod is tensioned under the action of external load in the later stage, the tensile stress generated by the external load is still smaller than the compression stress generated by the early tensioning on the slurry, the anchor rod slurry is still in a compression state, and the tensile stress generated by the external load on the anchor rod is provided by the soil body at the front section of the anchor rod, the total pullout resistance of the anchor rod is equal to the sum of the pullout resistance of the tension anchor rod and the pressure anchor rod, and then a small discount is formed, so that the pullout resistance of the anchor rod is very high, and the pullout resistance safety coefficient of the anchor rod is high.

And in the stretch-draw working period of the slowly-bonded steel strand, when the concrete of the protected structure reaches the designed stretch-draw strength after the concrete is poured, stretching the prestressed tendon, cutting off the redundant steel strand at the stretch-draw end, coating two epoxy resins on the exposed steel strand, the anchorage device, the clamping piece and the anchor plate surface at the stretch-draw end, and then sealing the anchorage device by using waterproof mortar.

Therefore, the anchor rod is not provided with a free section in the whole length, the natural slow bonding steel strand is not provided with a free section when passing through the reinforced structure 9, after the slow setting adhesive of the slow bonding steel strand is cured, the tensioning end position is completely combined with the concrete of the reinforced structure 9 through the slow bonding steel strand of the reinforced structure 9, the whole length of the slow bonding steel strand is combined with the grouting slurry 6 in the anchor rod hole channel in the anchoring section position, and then even if the clamping piece of the anchor 2 at the tensioning end and the supporting body of the anchoring section fail, the anchor rod can still normally work, the corrosion resistance is excellent, and the durability is good. In order to prevent the anchor rod from normally working in case of failure of the clamping piece at the tensioning end, when the thickness of the protected structure 9 is smaller than the prestress transmission length of the slow bonding prestress steel strand, the lower part of the protected structure is provided with an anchor rod bearing platform 10 to increase the anchoring length of the slow bonding prestress steel strand and the structure.

The construction process of the slow bonding prestressed anchor rod comprises the following steps:

1. cutting the retarded adhesive steel strand (namely the rib body 1) by a grinder according to the required length of the design for blanking.

2. And assembling a supporting body structure (comprising a supporting body 4, a spiral stirrup 7 and a construction frame vertical bar 8) of the slow bonding steel strand.

3. The positioning and drilling of the anchor rod can be carried out according to the design requirements, and the hole can be an equal-diameter hole or one or more enlarged head holes, and the hole is cleaned.

4. The whole set is put into the assembled slow bonding prestressed steel strand rod body.

5. The material for pouring the anchor rod drilling hole channel can be cement paste, cement mortar or concrete.

6. And chiseling floating slurry on the upper layer of the anchor rod, and excavating to manufacture the anchor rod bearing platform 10.

7. The reinforcing steel bars of the anchor rod bearing platform 10 of the reinforced structure 9 are installed, the anchor backing plate 3 at the tensioning end is installed, and the water swelling water stop strip 14 is installed.

8. And pouring concrete of the anchor bearing platform 10 of the reinforced structure 9.

9. After the concrete of the anchor rod bearing platform 10 of the reinforced structure 9 reaches the tension locking strength required by design, the anchor device 2 at the tension end is installed, and the anchor rod is locked and tensioned according to the design requirement.

10. And cutting the redundant slowly-bonded steel stranded wires at the tensioning end by using a grinding machine, wherein the length of the exposed clamping piece of the steel stranded wires is not less than 30 mm.

11. And coating two epoxy resins on the outer surfaces of the tensioning end anchorage device 2, the retarded adhesive steel strand 1 and the tensioning end anchor backing plate 3 for corrosion prevention, sealing the tensioning end by fine stone micro-expansion concrete or waterproof mortar, and ensuring that a prestressed steel strand protective layer is not less than 50 mm.

The utility model adopts the miniature pile type large-diameter slow-bonding prestress anti-pulling anchor rod without the free section, cancels the free section, after the reinforced structure concrete reaches the designed tensile strength, the retarded adhesive prestressed steel strand is tensioned and locked in the tensioning working period of the retarded adhesive prestressed steel strand, generally speaking, the tensioning working period of the retarded adhesive steel strand is 180 days, the standard anchoring period is 540 days, the time of the tensioning working period and the time of the standard curing period can be adjusted by a retarded adhesive steel strand factory according to the construction period, when the concrete is tensioned in the tensioning working period, the steel strand wires can freely extend like the unbonded steel strand wires, after the slowly-bonded steel strand wires are cured, the slowly-bonded steel strand wires can be completely bonded into a whole with the concrete of the reinforced structure and the grouting slurry of the anchoring section like common steel bars, and even if the clamping pieces of the anchorage devices at the tensioning ends rust and lose efficacy or the supporting bodies of the anchoring sections lose efficacy in the stress process, the anchor rods cannot lose efficacy. The durability of the anchor rod with the structure is greatly improved, the double-insurance effect is achieved, and the anchor rod can be applied to important permanent engineering, such as the anti-overturning stability reinforcement of a concrete dam, the anti-floating of a basement bottom plate, the stable anchoring of cable piers at two ends of a suspension bridge, the foundation anti-overturning stability anchoring of a large tower type starter in a port and the anti-overturning stability anchoring of a large power transmission and transformation line iron tower foundation.

The above embodiments are merely exemplary and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the utility model, and that such changes and modifications may be made without departing from the spirit and scope of the utility model.

Claims (10)

1. The utility model provides a no free section miniature stake formula major diameter slow bonding prestressing force resistance to plucking stock, the stock total length is the anchor section, does not establish the free section, the stock includes the muscle body, its characterized in that, the muscle body comprises many slow bonding steel strand wires, sets up one to the water swelling sealing rod of twice winding round in every slow bonding steel strand wires outside by reinforced structure's lower part, the stretching end of the muscle body is provided with ground tackle and anchor backing plate, and the anchor end of the muscle body is provided with anchor bearing structure, anchor bearing structure includes framework founding muscle, spiral stirrup and supporting body, and the anchor end is located the drilling bottom, all be full of grout body in the drilling.

2. A rock bolt according to claim 1, wherein the diameter of the bore hole is 300mm or more.

3. A rock bolt according to claim 1, wherein one or more anchoring carrier structures are provided within the anchoring section.

4. A rock bolt according to claim 1, wherein the anchoring sections are of equal diameter.

5. A rock bolt according to claim 1, wherein at least one enlarged head is provided in the anchoring section.

6. A rock bolt according to claim 5, wherein the enlarged head is cylindrical or spherical.

7. A rock bolt according to claim 1, wherein the tendon is bent into a U-shape at the carrier, and the carrier is a U-shaped steel plate.

8. The anchor according to claim 1, wherein an anchor platform is provided at a lower portion of the reinforced structure when a thickness of the reinforced structure is less than a prestress transmission length of the slow adhesion steel strand.

9. A rock bolt according to claim 1, wherein the grouting slurry is cement paste, cement mortar or concrete.

10. A rock bolt according to claim 1, wherein the carrier body is comprised of a steel plate and a compression sleeve.

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