US20040161305A1 - Radially deformed anchorage bolt - Google Patents

Radially deformed anchorage bolt Download PDF

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Publication number
US20040161305A1
US20040161305A1 US10/368,827 US36882703A US2004161305A1 US 20040161305 A1 US20040161305 A1 US 20040161305A1 US 36882703 A US36882703 A US 36882703A US 2004161305 A1 US2004161305 A1 US 2004161305A1
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United States
Prior art keywords
bolt
elongated
grout
tube
bore hole
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Abandoned
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US10/368,827
Inventor
Walter Simmons
Frank Locotos
James Staffler
Robert Macaul
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Terrasimco Inc
F M Locotos Co Inc
Maverick Tube Corp
Original Assignee
Terrasimco Inc
F M Locotos Co Inc
Maverick Tube Corp
Copperweld Marketing and Sales Co
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Publication date
Application filed by Terrasimco Inc, F M Locotos Co Inc, Maverick Tube Corp, Copperweld Marketing and Sales Co filed Critical Terrasimco Inc
Priority to US10/368,827 priority Critical patent/US20040161305A1/en
Assigned to COPPERWELD MARKETING AND SALES COMPANY reassignment COPPERWELD MARKETING AND SALES COMPANY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: STAFFLER, JAMES KEVIN
Assigned to TERRASIMCO, INC. reassignment TERRASIMCO, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SIMMONS, WALTER J., SIMMONS, WALTER N.
Assigned to F.M. LOCOTOS CO., INC. reassignment F.M. LOCOTOS CO., INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LOCOTOS, FRANK M., MACAUL, ROBERT T.
Assigned to MAVERICK TUBE CORPORATION reassignment MAVERICK TUBE CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: COPPERWELD MARKETING AND SALES COMPANY
Publication of US20040161305A1 publication Critical patent/US20040161305A1/en
Abandoned legal-status Critical Current

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    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/0026Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts

Abstract

A mine roof bolt for a grouted bore hole in a roof of a mine. The mine roof bolt includes an elongated member having a cross-sectional diameter less than that of the bore hole, a first end, and a second end. The elongated member has deformations such that axial tension on the bolt results in axial movement between the elongated member and the grout and results in confined compression of the grout between the bore hole and the elongated member surface to facilitate anchorage of the elongated member with grout to the mine rock in which the bore hole is disposed. The mine roof bolt includes a flange disposed adjacent to the second end. A method for supporting a mine roof. A method of making a mine roof bolt.

Description

    CROSS-REFERENCE
  • This application is related to contemporaneously filed U.S. patent application Ser. No. __/______ titled “Tubular Mining Bolt and Method”, by Frank M. Locotos, Walter J. Simmons, Walter N. Simmons, James Kevin Staffler and Robert T. Macaul, having attorney docket number LTV-1, incorporated by reference herein.[0001]
  • FIELD OF THE INVENTION
  • The present invention is related to industrial anchorage bolts which are widely used in several industrial fields, particularly in the mining industry to reinforce and support rock. Generally, the bolts are inserted into bore holes and anchored in place by a chemically reactive grouting that hardens in the space between the anchorage bolt and the bore hole wall. The present invention is specifically targeted at but not limited to hollow or tubular mine support bolts. [0002]
  • BACKGROUND OF THE INVENTION
  • The most common mine roof support system is the use of “headed rebar” bolts with polyester resin grouting. The bolts are made by forging a square head on standard steel rebar. The pattern on the rebar is typically an “X” pattern and is designed to provide mechanical “keying” with concrete in construction applications or with the polyester resin grouting in roof bolt applications. The mechanical “keying” provides exceptional initial strength with minimal movement of the bolt as load is applied. This system was introduced in the early 1970's and continues today. However, once the bolt loads to a point where the shear strength of the resin is exceeded or the shear strength between the resin and bore hole wall is exceeded, roof support will suddenly be lost. Initially, the characteristics of the deformed tubular bolt and rebar bolt will be very similar as load is applied. The difference will be seen at higher loads. The deformed tubular bolt will actually increase the anchorage strength as load is applied because it places the resin in confined compression, increasing the interfacial strengths. Rebar bolts or non-deformed tubular bolts on the other hand decrease the anchorage strength as load is applied because they place the resin grout in shear and tension decreasing the interfacial strengths. [0003]
  • FIG. 25 shows ideally how the deformed bolt performs in comparison to a grooved tube or rebar bolt. Initially, the smooth deformed bolt will have slightly higher deflections. As the load continues to increase (y axis), both bolts will reach their elastic limit and enter the plastic limit. Failure of the rebar bolt will occur when the resin shears. The holding power will suddenly drop off. After the resin shears with the standard rebar pattern, the maximum load capability usually falls to 1 to 4 tons which is the force required to move the bolt through the sheared resin grout. [0004]
  • The deformed tubular bolt will continue to absorb energy (hold load) because as it plastically yields it continues to place the resin in compression which increases the interfacial strength of the resin/elongated member and resin/bore hole wall. The greater the interfacial strengths, the better the anchorage. The area under the curves represents the total amount of energy the system will absorb. The greater the energy capability the better the roof support. [0005]
  • U.S. Pat. No. 4,750,887 (Simmons 1988) solved the problem of anchorage failure by the use of a solid bolt and nut that placed the resin in confined compression. This system works well and provides a failure mode similar to that shown in FIG. 25. This system has the disadvantage of only placing the resin grout at the very top of the bolt in compression and not distributing the load along a larger portion of the bolt. With the deformed tubular bolts, the confined compression can be achieved at numerous points along the bolt. In addition, U.S. Pat. No. 4,750,887 has the disadvantage of requiring treaded components that must work in an abrasive environment and requires a bore hole that is significantly larger than the bolt. [0006]
  • The present invention solves the problem of bolts pulling free from the grouting before the full strength of the bolt is achieved. [0007]
  • SUMMARY OF THE INVENTION
  • The present invention pertains to a mine roof bolt for a grouted bore hole in a roof of a mine. The mine roof bolt comprises an elongated member having a cross-sectional diameter less than that of the bore hole, a first end, and a second end. The elongated member has deformations such that axial tension on the bolt results in axial movement between the elongated member and the grout and results in confined compression of the grout between the bore hole and the elongated member surface to facilitate anchorage of the elongated member with grout to the mine rock in which the bore hole is disposed. The mine roof bolt comprises a flange disposed adjacent to the second end. [0008]
  • The present invention pertains to a method for supporting a mine roof. The method comprises the steps of moving a first end of a mine roof bolt through a grout capsule so grout from the grout capsule flows along the outer surface of an elongated member of the mine roof bolt which has deformations such that axial tension on the mine roof bolt results in axial movement between the elongated member and the grout and results in confined compression of the grout between the bore hole and the elongated member surface to facilitate anchorage of the mine roof bolt with the mine roof when the grout between the elongated member and the mine roof sets. There is the step of allowing the grout to set so the mine roof bolt is anchored to the mine roof in the bore hole. [0009]
  • The present invention pertains to a method of making a mine roof bolt. The method comprises the steps of placing an elongated member in a secure position. There is the step of forming deformations in the elongated member such that axial tension on the elongated member results in axial movement between the elongated member and the grout and results in confined compression of the grout between the bore hole and the elongated member surface to facilitate anchorage of the elongated member with grout to the mine rock in which the bore hole is disposed.[0010]
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • In the accompanying drawings, the preferred embodiment of the invention and preferred methods of practicing the invention are illustrated in which: [0011]
  • FIG. 1 is a schematic representation of a mine bolt of the present invention. [0012]
  • FIG. 2 is a bottom view of the mine bolt having a cross-section with at least one flat side. [0013]
  • FIG. 3 is a schematic representation of a cross-section of the tube of the mine bolt having a closed perimeter. [0014]
  • FIG. 4 is a schematic representation of a cross-section of a first end of the tube with a plug. [0015]
  • FIG. 5 is a schematic representation of a cross-section of the first end with a cap. [0016]
  • FIGS. 6, 7 and [0017] 8 are schematic representations of deformations in the tube with confined compression between the tube and the resin.
  • FIG. 9 is a schematic representation of a cross-section of a C-shaped tube filled with material. [0018]
  • FIG. 10 is a schematic representation of a spiral tube. [0019]
  • FIG. 11 is a schematic representation of a cross-section of a tube which is not welded. [0020]
  • FIG. 12 is a schematic representation of a cross-section of a C-shaped tube. [0021]
  • FIG. 13 is a schematic representation of a J-hook in the mine bolt. [0022]
  • FIG. 14 is a schematic representation of an anchor bolt in the mine. [0023]
  • FIG. 15[0024] a is a schematic representation of a tube having orthogonal crimps with a paddle end.
  • FIG. 15[0025] b is a schematic representation of a top view of the paddle end of the tube of FIG. 15a.
  • FIG. 16[0026] a is a schematic representation of a tube having orthogonal crimps with a cross end.
  • FIG. 16[0027] b is a schematic representation of a top view of the cross end of the tube of FIG. 16a.
  • FIG. 17[0028] a is an alternative embodiment of a tube having a swaged straight pattern with a cross end.
  • FIG. 17[0029] b is a schematic representation of a top view of the cross end of the tube of FIG. 17a.
  • FIG. 18[0030] a is a schematic representation of a tube having a swaged cone pattern with a cross end.
  • FIG. 18[0031] b is a schematic representation of a top view of the cross end of the tube of FIG. 18a.
  • FIG. 19 is a schematic representation of a side view of the tube with deformations. [0032]
  • FIG. 20 is a schematic representation of another side view of the tube with deformations. [0033]
  • FIG. 21 is a sectional view of FIG. 20. [0034]
  • FIG. 22 is a sectional view of FIG. 20. [0035]
  • FIG. 23 is a sectional view of FIG. 21. [0036]
  • FIG. 24 is a schematic representation of the mine bolt having an elongated member made of rebar. [0037]
  • FIG. 25 is a graph of confined compression failure versus resin shear failure.[0038]
  • DETAILED DESCRIPTION
  • Referring now to the drawings wherein like reference numerals refer to similar or identical parts throughout the several views, and more specifically to FIG. 1 thereof, there is shown a mine bolt [0039] 10 for a grouted bore hole 12 in a roof 14 of a mine. The mine bolt 10 comprises an elongated member, for example a tube 16 or a solid rod, such as rebar 44 as shown in FIG. 24, having a cross-sectional diameter less than that of the bore hole 12, a first end 20, and a second end 22. The elongated member has deformations 30 such that axial tension on the bolt results in axial movement between the elongated member and the grout 32 and results in confined compression of the grout 32 between the bore hole 12 and the elongated member surface to facilitate anchorage of the elongated member with grout 32 to the mine rock in which the bore hole 12 is disposed. The mine bolt 10 comprises a flange 24 disposed adjacent to the second end 22.
  • Preferably, the elongated member has deformations [0040] 30 such that increasing axial tension increases anchorage strength of the elongated member with the mine roof 14. The deformations 30 preferably form wedges 34 in the elongated member that compress the grout 32 and places the elongated member in radial/hoop compression when the elongated member experiences axial tension, as shown in FIGS. 6, 7 and 8. Preferably, the elongated member's surface is relatively smooth so that slip will occur between the elongated member and grout 32 and not between the grout 32 and the bore hole 12.
  • The deformations [0041] 30 preferably have an angle in the elongated member relative to the elongated member's longitudinal axis less than 45 degrees. Preferably, each deformation 30 has a sloped portion which has the angle in the elongated member relative to the elongated member's longitudinal axis less than 45 degrees. The deformations 30 preferably have a depth of 1% to 40% of the elongated member's diameter.
  • Preferably, the bolt includes a bearing plate [0042] 26 adapted to be disposed between the flange 24 and the roof surface 28 when the elongated member is in place in the bore hole 12. The flange 24 preferably holds the bearing plate 26 against at least 10,000 lbs. of load. Preferably, the elongated member is a tube 16 that has a hollow interior 18, as shown in FIG. 3. The first end 20 is preferably closed. The second end 22 is preferably open, but can be closed also. See U.S. Pat. No. 5,387,060 (Locotos), incorporated by reference herein. Preferably, the tube 16 has a circular cross-section, as shown in FIG. 3, or has at least one flat side, as shown in FIG. 2. The tube 16 preferably has a closed perimeter.
  • Preferably, the flange [0043] 24 is formed from the tube 16, and the flange 24 and the tube 16 are one continuous piece, as shown in FIGS. 19-23. The bolt can include a plug 36 that is disposed in proximity to the first end 20 to close the first end 20 of the tube 16, as shown in FIG. 4. Preferably, the bolt includes a cap 38 that fits to the first end 20 to close the first end 20 of the tube 16, as shown in FIG. 5.
  • The tube [0044] 16 preferably has a maximum cross-sectional dimension less than that of the diameter of the bore hole 12 and a minimum cross-sectional area of 45% of the cross-sectional area of the bore hole 12. Preferably, the second end 22 has either a round, square, hexagon or octagon shaped cross-section. The tube 16 is preferably made from steel. Preferably, the inside of the tube 16 is coated or filled to reduce corrosion, as shown in FIG. 9.
  • The tube [0045] 16 can be a metal sheet rolled into a spiral, as shown in FIG. 10. Alternatively, the tube 16 has a first edge and a second edge spaced from the first edge, as shown in FIG. 11. The tube 16 can have a cross-sectional shape of a C, as shown in FIG. 12. The elongated member can include a solid rod.
  • The present invention pertains to a method for supporting a mine roof [0046] 14. The method comprises the steps of moving a first end 20 of a mine bolt 10 through a grout capsule 56 so grout 32 from the grout capsule 56 flows along the outer surface of an elongated member of the mine bolt 10 which has deformations 30 such that axial tension on the mine bolt 10 results in axial movement between the elongated member and the grout 32 and results in confined compression of the grout 32 between the bore hole 12 and the elongated member surface to facilitate anchorage of the mine bolt 10 with the mine roof 14 when the grout 32 between the elongated member and the mine roof 14 sets. There is the step of allowing the grout 32 to set so the mine bolt 10 is anchored to the mine roof 14 in the bore hole 12.
  • Preferably, after the moving step, there is the step of rotating the elongated member of the mine bolt [0047] 10 disposed in the bore hole 12 from a second end 22 of the elongated member with a bolting machine connected to an insertion tool that contacts the second end 22. The moving step preferably includes the step of inserting the elongated member into the bore hole 12 until a bearing plate 26 in contact with a flange 24 of the mine bolt 10 in proximity to the second end 22 contacts the surface of the mine roof 28. Preferably, there is the step of increasing axial tension on the mine bolt 10 to increase anchorage strength of the mine bolt 10 in the bore hole 12.
  • The increasing the axial tension step preferably includes the step of compressing the grout [0048] 32 and placing the elongated member in compression with wedges 34 of the deformations 30 in the elongated member. Preferably, increasing the axial tension step includes the step of slipping the elongated member relative to the grout 32 and not the grout 32 relative to the bore hole 12. The moving step preferably includes the step of moving the first end 20 of a tube 16 which is closed through the grout capsule 56 so grout 32 from the grout capsule 56 will not enter the interior 18 of the tube 16 but flow along the outer surface of the tube 16 which has deformations 30 such that axial tension on the bolt results in axial movement between the tube 16 and the grout 32 and result in confined compression of the grout 32 between the bore hole 12 and the tube 16 surface to facilitate anchorage of the tube 16 with the mine roof 14 when the grout 32 between the tube 16 and the mine roof 14 sets.
  • The present invention pertains to a method of making a mine bolt [0049] 10. The method comprises the steps of placing an elongated member in a secure position, such as a vise. There is the step of forming deformations 30 in the elongated member such that axial tension on the elongated member results in axial movement between the elongated member and the grout 32 and results in confined compression of the grout 32 between the bore hole 12 and the elongated member surface to facilitate anchorage of the elongated member with grout 32 to the mine rock in which the bore hole 12 is disposed.
  • In the operation of the invention, distortions of the cylindrical bolt shape are employed so that any axial movement (deflection) of the bolt in the grout [0050] 32 will result in confined compression of the grout 32 between the bore hole 12 and bolt surface. To achieve maximum strength multiple distortions may be made along the length of the bolt in the grouted area. The bolt surface distortions should be made in such a way that axial tension on the bolt head will result in axial movement between the bolt and the grout 32 before axial movement between the grout 32 and the bore hole 12 in the area of the distortions.
  • The advantage of deformations [0051] 30 in the bolt are as follows.
  • Bolts do not slip out of grout [0052] 32 before full strength of the bolt is recognized
  • Increasing axial tension increases anchorage strength [0053]
  • Higher grout [0054] 32/bore hole 12 interfacial strength under load
  • Increased amount of energy required to break or remove bolt, thus providing safer anchorage [0055]
  • The deformations [0056] 30 can be used in any anchorage system that uses a grouted bolt. Some examples include but are not limited to mine roof 14 support, tunneling, industrial construction and concrete anchorage.
  • Deformations [0057] 30 of a smooth cylindrical bolt (tubular or solid) are employed so that axial movement of the bolt will create confined compression of the grout 32 between the bore hole 12 and bolt surface. Deformations 30 should be made perpendicular to the axis of the bolt in such a way that they cause an increase in the diameter of tube 16 perpendicular to both the deformation 30 direction and the bolt axis. It is preferred to have multiple deformations 30 along the length of the bolt in the grouted area. It is most preferred that consecutive distortions are in perpendicular directions.
  • Substantial improvement in the strength of anchorage bolts can be achieved by deforming the bolt surface that is in contact with the anchoring resin [0058] 32 (grout) so that when the bolt is loaded, it places the resin 32 in confined compression. This is achieved by swaging the tube 16 (or bolt) so as to form a truncated cone or by making orthogonal crimps in the tube 16. The object is to deform the bolt so that as it is loaded and moves axially, the bolt slips on the resin 32 placing the resin 32 in confined compression. FIGS. 15a and 15 b and 16 a and 16 b show two bolt embodiments (single embodiment with two different end closures, FIGS. 17a and 17 b show a swaged cone pattern with a cross end, and FIGS. 18a and 18 b show a swaged straight pattern with a cross end) that will accomplish confined compression. These FIGS. 15a-18 b show hollow bolts; however, the same concept can be achieved with solid bolts. The crimping method on hollow bolts is the most economically practical, as it requires the least force to accomplish the required amount of deformation 30.
  • The bolt surface distortions should be made in such a way that axial tension on the bolt head will result in axial movement between the bolt and the grout [0059] 32 before axial movement between the grout 32 and the bore hole 12 in the area of the distortions. If axial movement occurs first between the bore hole 12 wall and resin 32 and not between the bolt and resin 32, the resin 32 will not be subjected to confined compression and full strength will not be achieved.
  • FIG. 15[0060] a shows a tube 16 with orthogonal crimps with a paddle end (FIG. 15b) at the first end 20 of the tube 16, and a flange 24 in proximity to the second end 22 of the tube 16. The spreading from the orthogonal crimp does not exceed the maximum bore hole 12 diameter. The crimp spacing is about 2 inches, and can be closer than that. The first end 20 of the tube 16 is crimped and sheared to form a single paddle end at the center of the bolt. The diameter of the paddle after crimping does not exceed the maximum bore hole 12 diameter.
  • The deformations [0061] 30 formed from crimping preferably only appear in the portion of the tube 16 where grout 32 is present, although they could extend the length of the tube 16. If some type of an element, such as a J-hook 48, as shown in FIG. 13, or an anchor bolt 50, as shown in FIG. 14, is positioned inside the tube 16, then the tube 16 only has deformations 30 in its upper portion so that in the lower portion of the tube 16 there is a constant inside diameter for the element to better anchor to.
  • When an axial tension is placed on the bolt shown in FIG. 15[0062] a after the bolt has anchored to the rock about the bore hole 12 with grout 32, the grout 32 between the bolt surface that tapers or angles inwards is placed in confined compression. This can be understood by the fact that the surface of the bolt that is tapering or angling inwards towards the axis of the tube 16, as it is pulled down from the axial tension, presses against the resin 32 under it. The resin 32, which has hardened, essentially has nowhere to go, thus experiencing compression which receives some of the load forces and better holds the bolt against the load, similar to a vice, with the greater the load, the greater the vice holding force. This can be better understood by comparing it to a bolt without any deformations 30. In such an instance, as the load increases on a bolt having a constant diameter tube 16, there is no portion of grout 32 that is under any part of the bolt. The only forces present to hold the bolt to the bore hole 12 are the adhesive forces created by the grout 32 solidifying and binding to the rock of the bore hole 12 and the tube 16 surface of the bolt. Once the load forces are great enough, the adhesive bonds start to disintegrate, with the bolt ultimately separating from the bore hole 12. With the advantage of there being resin 32 under the inward angled portion of the deformations 30 of the tube 16, this resin 32 serves as a ledge or handle that the inward angled portion of the bolt better holds against the load. The portion of the resin 32 relative to the tube 16 shown in FIG. 15a that is in confined compression can be seen in FIG. 7.
  • FIG. 16[0063] a shows a tube 16 with orthogonal crimps with a cross end at the first end 20 (FIG. 16b), and a flange 24 in proximity to the second end 22. The cross end is formed by being crimped and sheared to form a cross paddle end at the center of the tube 16. The deformations 30 formed in the tube 16 are like those described above in regard to FIG. 15a. The portion of the resin 32 relative to the tube 16 shown in FIG. 16a that is in confined compression can be seen in FIG. 7.
  • FIG. 18[0064] a shows a tube 16 with a swaged cone pattern with a cross end at the first end 20 (FIG. 18b), and a flange 24 in proximity to the second end 22. The portion of the resin 32 relative to the tube 16 shown in FIG. 17a that is a confined compression can be seen in FIG. 6.
  • FIG. 17[0065] a shows a tube 16 with a swaged straight pattern with a cross end at the first end 20 (FIG. 17b), and a flange 24 in proximity to the second end 22. The portion of the resin 32 relative to the tube 16 shown in FIG. 18a that is in confined compression can be seen in FIG. 8.
  • The deformations [0066] 30 necessary to achieve superior holding power must be made such that axial tension on the bolt flange 24 results in axial movement between the tube 16 and the resin 32 and result in confined compression of the resin 32 between the bore hole and tube 16 surface. The deformations 30 are made so that they form wedges 34 that compress the resin 32 and place the tube 16 in radial/hoop compression. The tube 16 surface must be relatively smooth so it slips in the resin 32 and provides confined compression of the resin 32. In other words, the resin 32 should not adhere to the tube 16, the tube 16 should slip slightly through the resin 32. Once it starts to slip, it acts like a “Chinese handcuff”, the harder you pull, the greater the anchorage strength.
  • The deformations [0067] 30 should be made in the tube 16 so that the angle of the deformation 30 made relative to the bolt axis is less than 45 degrees and preferably less than 10 degrees, as shown in FIGS. 6, 7 and 8. This assures that the resin 32 will be in confined compression instead of shearing. The depth of the deformation 30 should be in the range of 0.010 inches to 0.300 inches. This type of deformations 30 is desirable in solid bolts also.
  • The deformation [0068] 30 pattern on the first end 20 of the tube 16 is cold formed using a 50 ton adjustable stroke, high speed hydraulic press. Upon actuating the ram, two containment dies are closed together simultaneously. When closed these two matching die halves contain the OD of the tubing while approximately 40 tons of force is used to form the deformation 30 pattern, as shown in FIG. 22. The containment die is a circumferential die with a bore diameter of 1.300″. The deformation 30 pattern is created by the continuing stroke of the press which closes two duplicate forming dies onto the tubing, 180 degrees apart. The forming dies are made up of three 1½″ diameter circular pins equally spaced at 4″ center-to-center. These pins indent/deformation 30 the tube 16 with a {fraction (3/16)}″ deep oval pattern. These forming dies compress the tubing to form a similar three deformation 30 pattern on opposite sides of the tube 16. The press then cycles back on top, opens the dies and the tube 16 is removed from the die set with the completed deformation 30 pattern in place.
  • The bead or flange [0069] 24 on the second end 22 of the bolt is hot formed using an induction heating process and a hydraulic forging machine. Approximately 1¾″ of the tube 16 end is inserted into an induction heating coil to heat the tube 16 end to a nominal temperature of 1525 degrees Fahrenheit. The tube 16 is then placed into the hydraulic forging machine which forces the heated tube 16 end into a forming die with a resultant force of approximately 15,000 pounds. This axial movement of the tube 16 into the forming die causes the midpoint of the heated area to bulge/deform outwards and form the beaded end, as shown in FIG. 23. The contours and dimensions of the beaded end are controlled by the following; steel tubing properties, the length of stroke of the hydraulic forging machine, the length of the heat affected zone and the level of heat induced into the tubing end. After forming the beaded end, the tube 16 is removed from the forging machine and is immediately submersed into a cooling tank filled with water to quench the tube 16 and establish a microstructure which gives the end ductility for resistance to failure. Additional information regarding a tube bolt can be found in U.S. patent application Ser. No. __/______ titled “Tubular Mining Bolt and Method”, incorporated by reference herein.
  • Although the invention has been described in detail in the foregoing embodiments for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be described by the following claims. [0070]

Claims (32)

What is claimed is:
1. A mine roof bolt for a grouted bore hole in a roof of a mine comprising:
an elongated member having a cross-sectional diameter less than that of the bore hole, a first end, and a second end, the elongated member has deformations such that axial tension on the bolt results in axial movement between the elongated member and the grout and results in confined compression of the grout between the bore hole and the elongated member surface to facilitate anchorage of the elongated member with grout to the mine rock in which the bore hole is disposed; and
a flange disposed adjacent to the second end.
2. A bolt as described in claim 1 wherein the elongated member has deformations such that increasing axial tension increases anchorage strength of the elongated member with the mine roof.
3. A bolt as described in claim 2 wherein the deformations form wedges in the elongated member that compress the grout and place the elongated member in compression when the elongated member experiences axial tension.
4. A bolt as described in claim 3 wherein the elongated member's surface is relatively smooth so that slip will occur between the elongated member and grout and not between the grout and the bore hole.
5. A bolt as described in claim 4 wherein the deformations have an angle in the elongated member relative to the elongated member's longitudinal axis less than 45 degrees.
6. A bolt as described in claim 5 wherein each deformation has a sloped portion which has the angle in the elongated member relative to the elongated member's longitudinal axis less than 45 degrees.
7. A bolt as described in claim 6 wherein the deformations have a depth of 1% to 40% of the elongated member's diameter.
8. A bolt as described in claim 7 including a bearing plate adapted to be disposed between the flange and the roof surface when the elongated member is in place in the bore hole.
9. A bolt as described in claim 8 wherein the flange holds the bearing plate against at least 10,000 lbs. of load.
10. A bolt as described in claim 9 wherein the elongated member is a tube that has a hollow interior.
11. A bolt as described in claim 10 wherein the first end is closed.
12. A bolt as described in claim 11 wherein the tube has a circular cross-section or has at least one flat side.
13. A bolt as described in claim 12 wherein the tube has a closed perimeter.
14. A bolt as described in claim 13 wherein the flange is formed from the tube, wherein the flange and the tube are one continuous piece.
15. A bolt as described in claim 14 including a plug that is disposed in proximity to the first end to close the first end of the tube.
16. A bolt as described in claim 14 including a cap that fits to the first end to close the first end of the tube.
17. A bolt as described in claim 14 wherein the tube has a maximum cross-sectional dimension less than that of the diameter of the bore hole and a minimum cross-sectional area of 45% of the cross-sectional area of the bore hole.
18. A bolt as described in claim 17 wherein the second end has either a round, square, hexagon or octagon shaped cross-section.
19. A bolt as described in claim 18 wherein the tube is made from steel.
20. A bolt as described in claim 19 wherein the inside of the tube is coated or filled to reduce corrosion.
21. A bolt as described in claim 9 wherein the tube is a metal plate rolled into a spiral.
22. A bolt as described in claim 9 wherein the tube has a first edge and a second edge spaced from the first edge.
23. A bolt as described in claim 22 wherein the tube has a cross-sectional shape of a C.
24. A bolt as described in claim 9 wherein the elongated member is a solid rod.
25. A method for supporting a mine roof comprising the steps of:
moving a first end of a mine roof bolt through a grout capsule so grout from the grout capsule flows along the outer surface of an elongated member of the mine roof bolt which has deformations such that axial tension on the mine roof bolt results in axial movement between the elongated member and the grout and results in confined compression of the grout between the bore hole and the elongated member surface to facilitate anchorage of the mine roof bolt with the mine roof when the grout between the elongated member and the mine roof sets; and
allowing the grout to set so the mine roof bolt is anchored to the mine roof in the bore hole.
26. A method as described in claim 25 including after the moving step, there is the step of rotating the elongated member of the mine roof bolt disposed in the bore hole from a second end of the elongated member with a bolting machine connected to an insertion tool that contacts the second end.
27. A method as described in claim 26 wherein the moving step includes the step of inserting the elongated member into the bore hole until a bearing plate in contact with a flange of the mine roof bolt in proximity to the second end contacts the surface of the mine roof.
28. A method as described in claim 27 including the step of increasing axial tension on the mine roof bolt to increase anchorage strength of the mine roof bolt in the bore hole.
29. A method as described in claim 28 wherein the increasing the axial tension step includes the step of compressing the grout and placing the elongated member in compression with wedges of the deformations in the elongated.
30. A bolt as described in claim 29 wherein the increasing the axial tension step includes the step of slipping the elongated member relative to the grout and not the grout relative to the bore hole.
31. A method as described in claim 30 wherein the moving step includes the step of moving the first end of a tube which is closed through the grout capsule so grout from the grout capsule will not enter the interior of the tube but flow along the outer surface of the tube which has deformations such that axial tension on the bolt results in axial movement between the tube and the grout and result in confined compression of the grout between the bore hole and the tube surface to facilitate anchorage of the tube with the mine roof when the grout between the tube and the mine roof sets.
32. A method of making a mine roof bolt comprising the steps of:
placing an elongated member in a secure position: and
forming deformations in the elongated member such that axial tension on the elongated member results in axial movement between the elongated member and the grout and results in confined compression of the grout between the bore hole and the elongated member surface to facilitate anchorage of the elongated member with grout to the mine rock in which the bore hole is disposed.
US10/368,827 2003-02-19 2003-02-19 Radially deformed anchorage bolt Abandoned US20040161305A1 (en)

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PCT/US2004/004774 WO2004074636A2 (en) 2003-02-19 2004-02-18 Radially deformed anchorage bolt

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EP1762699A1 (en) * 2005-09-07 2007-03-14 MKT Metall-Kunststoff-Technik GmbH & Co. KG Anchoring rod
US20070175127A1 (en) * 2004-08-18 2007-08-02 Taisei Corporation Shearing force reinforced structure and member
US20080219775A1 (en) * 2007-03-09 2008-09-11 Frederic Mercier-Langevin Bolt assembly
US20100166505A1 (en) * 2003-12-18 2010-07-01 R&B Leasing, Llc Self-centralizing soil nail and method of creating subsurface support
US20100166506A1 (en) * 2003-12-18 2010-07-01 R&B Leasing, Llc Composite self-drilling soil nail and method
WO2010118462A1 (en) * 2009-04-16 2010-10-21 Gazmick Pty Ltd A friction stabiliser
CN102733851A (en) * 2012-07-05 2012-10-17 大同煤矿集团有限责任公司 Control method for water-containing collapse columns in mining affected areas of combined reconstructed mines
US8376661B2 (en) 2010-05-21 2013-02-19 R&B Leasing, Llc System and method for increasing roadway width incorporating a reverse oriented retaining wall and soil nail supports
US9010165B2 (en) 2011-01-18 2015-04-21 Nucor Corporation Threaded rebar manufacturing process and system
WO2015085349A1 (en) * 2013-12-12 2015-06-18 Garock Pty Ltd Ground support apparatus and method
US9551150B2 (en) 2010-06-24 2017-01-24 Nucor Corporation Tensionable threaded rebar bolt
CN109072697A (en) * 2016-04-12 2018-12-21 安百拓凿岩有限公司 Method and apparatus for rock reinforcement

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Cited By (18)

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Publication number Priority date Publication date Assignee Title
US8851801B2 (en) * 2003-12-18 2014-10-07 R&B Leasing, Llc Self-centralizing soil nail and method of creating subsurface support
US9273442B2 (en) 2003-12-18 2016-03-01 R&B Leasing, Llc Composite self-drilling soil nail and method
US20100166505A1 (en) * 2003-12-18 2010-07-01 R&B Leasing, Llc Self-centralizing soil nail and method of creating subsurface support
US20100166506A1 (en) * 2003-12-18 2010-07-01 R&B Leasing, Llc Composite self-drilling soil nail and method
US20070175127A1 (en) * 2004-08-18 2007-08-02 Taisei Corporation Shearing force reinforced structure and member
US7823356B2 (en) * 2004-08-18 2010-11-02 Taisei Corporation Shearing force reinforced structure and member
EP1762699A1 (en) * 2005-09-07 2007-03-14 MKT Metall-Kunststoff-Technik GmbH & Co. KG Anchoring rod
US20080219775A1 (en) * 2007-03-09 2008-09-11 Frederic Mercier-Langevin Bolt assembly
WO2010118462A1 (en) * 2009-04-16 2010-10-21 Gazmick Pty Ltd A friction stabiliser
CN102405329A (en) * 2009-04-16 2012-04-04 盖斯米克私人有限公司 A friction stabiliser
US8708597B2 (en) 2010-05-21 2014-04-29 R&B Leasing, Llc System and method for increasing roadway width incorporating a reverse oriented retaining wall and soil nail supports
US8376661B2 (en) 2010-05-21 2013-02-19 R&B Leasing, Llc System and method for increasing roadway width incorporating a reverse oriented retaining wall and soil nail supports
US9551150B2 (en) 2010-06-24 2017-01-24 Nucor Corporation Tensionable threaded rebar bolt
US9010165B2 (en) 2011-01-18 2015-04-21 Nucor Corporation Threaded rebar manufacturing process and system
US9855594B2 (en) 2011-01-18 2018-01-02 Nucor Corporation Threaded rebar manufacturing process and system
CN102733851A (en) * 2012-07-05 2012-10-17 大同煤矿集团有限责任公司 Control method for water-containing collapse columns in mining affected areas of combined reconstructed mines
WO2015085349A1 (en) * 2013-12-12 2015-06-18 Garock Pty Ltd Ground support apparatus and method
CN109072697A (en) * 2016-04-12 2018-12-21 安百拓凿岩有限公司 Method and apparatus for rock reinforcement

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