US20070297862A1 - Rock bolt with grout flow geometry - Google Patents

Rock bolt with grout flow geometry Download PDF

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Publication number
US20070297862A1
US20070297862A1 US11/699,347 US69934707A US2007297862A1 US 20070297862 A1 US20070297862 A1 US 20070297862A1 US 69934707 A US69934707 A US 69934707A US 2007297862 A1 US2007297862 A1 US 2007297862A1
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United States
Prior art keywords
bolt
tip
geometry
pilot hole
reinforcement device
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Abandoned
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US11/699,347
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English (en)
Inventor
Luis Giraldo
Steven Cotten
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Raytheon Co
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Raytheon UTD Inc
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Priority to US11/699,347 priority Critical patent/US20070297862A1/en
Assigned to RAYTHEON UTD INC. reassignment RAYTHEON UTD INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: COTTEN, STEVEN, GIRALDO, LUIS
Publication of US20070297862A1 publication Critical patent/US20070297862A1/en
Assigned to RAYTHEON COMPANY reassignment RAYTHEON COMPANY MERGER (SEE DOCUMENT FOR DETAILS). Assignors: RAYTHEON UTD INC.
Abandoned legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
    • E21D21/004—Bolts held in the borehole by friction all along their length, without additional fixing means
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts

Definitions

  • the present invention relates to substrate supporting bolts and methods of using such bolts.
  • Underground mining has one of the highest fatal injury rates of any industry in the United States, more than five times the national average compared to other industries.
  • roof falls in mines continue to be one of the greatest safety hazards encountered in underground mines.
  • approximately 50% of all fatalities in underground mines have been due to ground falls.
  • mines are forced to satisfy coal demand by working in areas with more challenging geologic and associated ground control conditions.
  • Grouted and mechanical expansion anchor rock bolts have been by far the most common means used to secure and stabilize mine roofs and ribs, together comprising over 99% of rock bolts used in coal mines in the United States.
  • Rock bolts typically support mine roofs either by beam building (the tying together of multiple rock layers so they perform as a larger single beam), suspension of weak fractured ground from more competent layers, formation of a pressure arch, or support of discrete blocks.
  • Both grouted and mechanical expansion anchor rock bolt support techniques involve drilling pilot holes in the rock and establishing anchorage in those holes.
  • a decline in the use of mechanical bolts and an increase in grouted bolts is attributed to the fact that grouted rock bolts distribute their anchoring load on the rock over a greater area and therefore generally have superior anchorage capacity.
  • the application of grouted rock bolts for ground control is not without problems, several of which are exaggerated in the presence of mechanically weak rock.
  • FIG. 1A provides a schematic representation of a grouted rock bolt anchoring technique.
  • FIG. 1B provides a schematic representation of a mechanical expansion rock bolt anchoring technique.
  • the grouted bolt 101 shown in FIG. 1A is a rebar bolt having a threaded end 109 protruding from the pilot hole 118 .
  • the rebar 103 is surrounded by resin, or grout, 105 and is fashioned with a face plate 107 held in place by a nut 111 .
  • the mechanically anchored bolt 102 shown in FIG. 1B has a threaded tip 106 and a threaded end 108 .
  • the tip 106 is screwed into the mechanical anchor 110 , which expands during the process.
  • the threaded end 108 is fashioned with a face plate 112 , washer 116 , and nut 114 .
  • Other styles of such bolts may have a forged end shaped like a nut ( 208 , FIG. 2 ), instead of a threaded end 108 .
  • FIG. 2 illustrates the cylindrical geometry of the blunt insertion tip 206 of a typical grouted rock bolt 202 with a forged head 208 .
  • the rock bolt's tip 206 has no modifications for the bolt 202 to interact with grouting material in any significant way.
  • FIGS. 3A through 3C schematically illustrate the sequence of events related to installation of such a rock bolt 202 for grout anchoring in a mine roof 313 (however, such a process and bolt could be used to secure any substrate).
  • a sealed cartridge 320 of two-component grout 305 is inserted into the pilot hole 318 .
  • the roof bolt 202 is then inserted in the hole 318 .
  • the roof bolt 202 is then rapidly rotated and simultaneously advanced into the hole 318 .
  • the advancing blunt tip 206 of the bolt compresses the sealed grout cartridge 320 , thereby expanding the cartridge wrapper 322 until it has completely filled the end of the pilot hole 318 .
  • the bolt 202 may penetrate several inches into the volume occupied by the grout cartridge 320 before the cartridge wrapper 322 fails and releases the contained grouting material 305 , building up significant pressure within the grout 305 . Once the wrapper 322 bursts, the rotating bolt 202 continues to advance through the grout 305 , mixing its components and pushing the mixed grout back along the length of the bolt 202 through the narrow annulus 315 formed between the roof bolt 202 and the wall of the pilot hole 318 .
  • the grout 305 then at least partially surrounds the fully inserted bolt 202 and, upon curing, bonds the bolt 202 to the roof material 313 with the intent of enhancing the overall integrity of the mine roof 313 .
  • Less than the complete length of the bolt 202 may be surrounded by the grouting material 305 due to insufficient mixing and transport of the grouting material 305 by the bolt 202 .
  • the relatively smooth surface, even in a textured rebar ( 103 , FIG. 1A ), and blunt tip 206 are not configured to perform this mixing and transport.
  • Very weak roof conditions are increasingly being encountered in underground coal mines.
  • Zhang et. al. Abstract: “Design Considerations of Roof Bolting under Very Weak Roof Conditions”, to be presented at the 2006 SME Annual Meeting and Exhibit technical presentation, the disclosure of which is incorporated by reference herein, it was found that in the Illinois Basin, the more easily mined reserves with more competent roof rock are rapidly being depleted, and the higher quality, lower sulfur coals are more strongly associated with weaker, laminated roof rock. Roof bolting under less competent roof conditions in underground coal mines often encounters difficulties not only because the roof has very low inherent mechanical strength but also because it composed of thin laminations of different rock types.
  • grout may be injected laterally into the roof external to the pilot hole (also known as grout migration), thereby separating the rock layers and reducing the length of bolt encapsulation within the grouting material.
  • Loss of grout through lateral grout migration also has the effect of reducing the length of the grout column, which has a significant effect on the design assumptions and stability of mine openings. Additionally, grouted bolts with reduced encapsulation due to reduced length of the grout column may allow the body of the bolt to come in contact with the mine environment with the potential for corrosion and eventual degradation of the roof support system. In some instances, as is the case of mines with high levels of hydrogen sulfide inherent within the roof rock, the corrosive effects are accentuated and the need for full encapsulation of the bolts becomes even more important.
  • a field test program by the Inventors using different grout types, insertion speeds, and annulus sizes was specifically designed to characterize the forces required for standard, blunt end bolt insertion.
  • the tests consisted of pushing bolts having blunt ends at constant speed, without rotation, into grout-filled pilot holes in a mine roof (the substrate).
  • a load cell was installed between the drill head and the bolt to measure load.
  • An extensometer was used to measure bolt displacement. Values of load and displacement were simultaneously measured.
  • the test plan called for three bolting systems employing standard rebar bolts, two grout types and two insertion speeds. Twelve combinations of these parameters are possible and two (2) tests were to be performed for each combination for a total of 24 tests.
  • the bolt systems were: (a) a #6 (0.75 inch diameter) bolt in 1.03′′ diameter hole; (b) a #6 (0.75 inch diameter) bolt in 1.25′′ diameter hole; and (c) a #7 (0.875 inch diameter) bolt in 1.375′′ diameter hole all using 6-foot long standard headed rebar bolts.
  • the grout types tested were Minova LIF and Fasloc low viscosity, both with a two (2) minute set time.
  • Grout cartridges of 0.9, 1.125, and 1.25 inch diameters and appropriate total length were used to match each of the bolting systems.
  • the insertion speeds of the bolts into the pilot holes were 4.5 and 7 inches per second. These tests allowed measurement of insertion force and demonstrated how the test parameters interact to generate the pressure front ahead of the bolt tip. As expected, the force required to push the bolt into the grout-filled borehole increased with the depth of bolt insertion.
  • the load curves observed were similar for the two types of grout employed, and no significant difference in the load ranges were recorded during the tests. However, in some instances, the early generation of higher pressure triggered hydraulic fracturing of the roof followed by resin loss, which in turn reduced the observed length of bolt encapsulation.
  • Load (force) of insertion vs. depth was plotted for each of the tests. All of the plots exhibited a common behavior, and three distinct load regions were identified as indicated in FIG. 4 .
  • the initial insertion load increased at a constant and relatively low rate up to around 20 inches of insertion (Region I of the graph).
  • the load increased at an accelerated rate for a short interval (Region II of the graph) after which the load rate declined to a rate slightly greater than the initially observed rate (Region III of the graph).
  • Region I was well defined in most of the tests. Regions II and III exhibited more variability and in some cases overlapped.
  • the graph of FIG. 4 suggests that the following effects take place.
  • Region I there was a compression of the intact grout cartridge with a Poisson effect on the cartridge. That is, as the length of cartridge was compressed, it expanded within the hole until the first region transition was reached. Since the cartridge had now filled the hole, the pressure increased until the rupturing strength of the cartridge wrapper was exceeded. Once the wrapper ruptured, fluid flow of the grout began similar to flow of water in a pipe, albeit the grout is much more viscous than water. The flow rate remained constant since the speed of insertion was maintained constant and the load increased proportionally to the length of bolt insertion. In some instances, the early generation of higher pressure triggered hydraulic fracturing of the roof followed by resin loss, which in turn reduced the observed length of bolt encapsulation.
  • the invention relates to modifications to and improvements on existing grouted bolt design and practice, which have the aim of improving bolt anchorage performance in all circumstances, particularly where rock with low compressive strength or laminated structure is encountered.
  • An exemplary embodiment of the invention includes a modified geometry in the tip of a rock bolt first inserted into a pilot hole.
  • the modified geometry provides a physical means to facilitate the flow of grout past the end of the bolt, promote distribution of the grout in the annulus formed between the bolt and the pilot hole and/or facilitate the rupture of the grout material container in the pilot hole.
  • improvement in grouted rock bolt system performance is achieved by modifying the tip of the rock bolt to have an auger shape, which facilitates grout flow and mixing in the borehole allowing increased anchorage capacity of each bolt by providing a longer grout column, increases the effective thickness of the structure formed by the bonding of the bolt in the supported roof, and reduces the potential for corrosion of the bolt by reducing the length of bolt exposed to the mine environment.
  • the rock bolt tip has a geometry modified to have a physical means for facilitating rapid rupture of a sealed grout cartridge and thereby reducing pressure build up of the grout within the cartridge. Reducing internal grout pressure during bolt installation allows reduction of the potential for hydraulic fracturing of the roof rock, increases the effective length of bolt encapsulation by preventing loss of grout into the roof rock, reduces bolt “gloving” by preventing cartridge expansion caused by internal grout pressure during installation, and improves bolt anchorage capacity as a result of reduced bolt gloving and increased bolt encapsulation.
  • FIG. 1A is a schematic representation of a grouted rock bolt and anchoring technique.
  • FIG. 1B is a schematic representation of a mechanical expansion rock bolt and anchoring technique.
  • FIG. 2 is a representation of the blunt insertion end of a conventional grouted bolt.
  • FIGS. 3A, 3B , and 3 C show steps stages in a conventional installation of a grout anchored bolt in substrate, such as a mine roof.
  • FIG. 4 is a graph of insertion load (force) vs. depth of insertion representing a series of field test observations using conventional rock bolts.
  • FIG. 5 shows a rock bolt having a modified geometry in accordance with the invention.
  • FIG. 6 shows a rock bolt having a modified geometry in accordance with the invention.
  • FIG. 7 shows a rock bolt having a modified geometry in accordance with the invention
  • FIG. 8 shows a rock bolt having a modified geometry in accordance with the invention
  • FIG. 9 shows a rock bolt having protuberances for improved holding capacity, but without a modified tip geometry in accordance with the invention.
  • FIG. 10 shows a rock bolt having protuberances for improved holding capacity and a modified tip geometry in accordance with the invention.
  • FIG. 11 is a graph showing grip factor vs. bolt type illustrating the improved grip factor of rock bolts, both conventional and in accordance with the invention.
  • FIG. 12 shows a rock bolt having protuberances for improved holding capacity and a modified tip geometry in accordance with the invention.
  • Embodiments of the invention relate to a rock bolt for reinforcing a substrate, for example, the roof of a mine.
  • the rock bolt has a modified geometry at the tip first inserted into a pilot hole.
  • the modified geometry provides a physical means to facilitate the flow of grout past the end of the bolt, promote distribution of the grout in the annulus formed between the bolt and the pilot hole and/or facilitate the rupture of the grout material container in the pilot hole.
  • the rock bolts and methods of the invention can be used with holes drilled and rock bolts formed in accordance with the subject matter described in U.S. patent application Ser. No. 10/919,271, the entirety of which is incorporated by reference herein. The invention will now be described with reference to the drawings.
  • Various embodiments of the invention eliminate the blunt insertion end of typical grouted bolts and utilize a modified bolt tip geometry.
  • This geometry can provide a smaller cross-sectional area at the tip of the bolt, a pumping effect, or both, similar to that of an auger, as the bolt is spun up into the hole during the normal bolt installation process.
  • This pumping effect promotes the flow of grout through the annulus between the rock bolt and the pilot hole thereby reducing the pressure gradient as the bolt is inserted through the grout material, thereby minimizing the overall maximum pressure within the pilot hole.
  • FIG. 5 shows a rock bolt 502 according to an exemplary embodiment of the invention that has an auger shaped tip 508 .
  • the auger shape forces the grout material to mix and travel down past the tip 508 .
  • the grout material is pushed down along the length of the rock bolt 502 as the bolt 502 is rotated deeper into the pilot hole.
  • the extreme tip 506 of the rock bolt 502 has a reduced cross-sectional area.
  • FIG. 6 Another exemplary embodiment of the invention is shown at FIG. 6 .
  • the extreme tip 606 of the rock bolt is blunted as in a conventional bolt
  • the tip 608 below the extreme end has a modified geometry.
  • the auger shape of this modified geometry comes into effect as the tip 608 is inserted into the grout material or into the container holding the grout material. Once the container is ruptured, the auger-shaped tip geometry mixes the grout and pushes it down the length of the rock bolt 602 .
  • the actual leading edge geometry of the bolt, auger pitch, and other physical requirements of this rock bolt can be configured based on bolt diameter, pilot hole diameter, grout viscosity, bolt insertion rate, and bolt rotation rate.
  • the goal of the tip geometry configuration is to optimize the geometry with respect to these operational parameters to maximize grout flow around the bolt and minimize the rate of grout pressure increase within the pilot hole.
  • FIG. 9 shows an HRB-E rock bolt 902 , such as is described in U.S. patent application Ser. No. 10/919,271, which has protrusions 910 at its tip 908 for cutting a pilot hole groove, but without an auger shaped modification.
  • the HRB-E rock bolt 902 has an extreme tip 906 that is flat. As the HRB-E rock bolt 902 is inserted in a borehole, the protrusions 910 create a groove in the borehole wall and produce rock cuttings that mix into the grout.
  • FIG. 10 shows an HRB-EP rock bolt 1002 having a tip 1008 modified in accordance with an embodiment of the invention to have an auger shape for transporting grout material.
  • the HRB-EP rock bolt 1002 also has protrusions 910 and an extreme tip 1006 that is flat.
  • FIG. 11 is a chart comparing average grip factor (the anchoring force of an installed rock bolt) to bolt type for an HRB-E rock bolt 902 as shown in FIG. 9 , an HRB-EP rock bolt 1002 as shown in FIG. 10 , and Standard, DP103, and DP125 rock bolts.
  • the HRB-EP rock bolt 1002 has a greater average grip factor, e.g., 1.01 ton/in, than the other rock bolts.
  • FIG. 11 shows that the HRB-EP rock bolt 1002 with a tip 1008 having a pump feature in accordance with an embodiment of the invention produced more consistent anchorage capacity than the HRB-E rock bolt 902 , which is a similar bolt, but lacks the pump feature.
  • the pump feature directs the grout flow in a manner that enhances the mixing of the rock cuttings and produces the observed results during testing.
  • the grout pumping feature of the rock bolts can be used in conjunction with other helical rock bolt enhancements to improve grout flow and reduce the pressure of bolt insertion ahead of the bolt, which may cause loss of grout laterally into the strata.
  • These enhancements may include the addition of a grout cartridge puncturing feature, as discussed below, and the use of rebar with a thread-like pattern to promote the flow of grout in the direction of the bolt head and reduce the pressure gradient within the grout.
  • the pressure gradient of Region II is reduced or eliminated by replacing the blunt, piston-like end of a typical grouted rock bolt with a modified tip having an extreme tip with a geometry that rapidly ruptures the grout cartridge.
  • Earlier cartridge rupture reduces the maximum pressure attained in Region II, shown in FIG. 4 , which is the interval of most the rapid grout pressurization.
  • Use of this new geometry helps prevent grout pressure reaching a magnitude sufficient to fracture the surrounding rock by rupturing the grout cartridge inside the borehole.
  • Experiments by the inventors at the San Juan Mine in New Mexico show that early rupture of the cartridge prevents pressure buildup and reduces the possibility of hydraulic fracturing of the substrate into which the rock bolt is inserted, which would cause grout loss and hinder full encapsulation.
  • the tip geometry of the rock bolt 702 shown in FIG. 7 has a chisel shape. This shape facilitates the rapid rupture of a grout material container within a pilot hole upon insertion of the rock bolt therein. Such a configuration maintains considerable strength of the rock bolt tip 708 and can pierce the grout container whether rotated or not.
  • FIG. 8 Another exemplary embodiment of the invention is shown in FIG. 8 .
  • the extreme tip 806 of the tip 808 of the rock bolt 802 of this embodiment has multiple piercing features for a rupturing geometry. This embodiment can pierce the grout container whether rotated or not, but is preferably rotated during insertion.
  • the leading edge geometry of the rock bolt in accordance with FIGS. 7 and 8 can be determined by the measured strength of the grout material cartridge wrapper, the cartridge diameter, the pilot hole diameter, the grout viscosity, the bolt insertion rate, and the ability of available manufacturing processes to create a specific geometry.
  • the goal of these embodiments of the invention is to optimize the modification of the bolt end geometry with respect to these operational parameters to accelerate grout cartridge rupture and minimize the ultimate grout pressure within the pilot hole.
  • FIG. 12 shows a rock bolt 1202 incorporating a tip 1208 having an auger shape for transporting grouting material, an extreme tip 1206 having a rupturing geometry with multiple piercing features for rupturing a grout material container, and protrusions 1210 at its tip 1208 for forming a groove in a pilot hole wall.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Piles And Underground Anchors (AREA)
  • Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
  • Joining Of Building Structures In Genera (AREA)
US11/699,347 2006-01-31 2007-01-30 Rock bolt with grout flow geometry Abandoned US20070297862A1 (en)

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US76337006P 2006-01-31 2006-01-31
US11/699,347 US20070297862A1 (en) 2006-01-31 2007-01-30 Rock bolt with grout flow geometry

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US (1) US20070297862A1 (zh)
CN (1) CN101029571A (zh)
AU (1) AU2007200391A1 (zh)
CA (1) CA2576116A1 (zh)
DE (1) DE102007006277A1 (zh)
GB (1) GB2434626A (zh)
PL (1) PL381631A1 (zh)
RU (1) RU2007103541A (zh)
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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090290941A1 (en) * 2008-05-21 2009-11-26 Hilti Aktiengesellschaft Setting method for anchoring a fastening element
US20110033246A1 (en) * 2009-08-05 2011-02-10 F.M. Locotos Co., Inc. Tensionable tubular resin anchored tubular bolt and method
US20120155970A1 (en) * 2010-12-15 2012-06-21 Fci Holdings Delaware, Inc. Mine Roof Bolt With End Fitting
WO2016141008A1 (en) * 2015-03-03 2016-09-09 J-Lok Co. Pumpable two component resin
US10253628B2 (en) 2016-09-02 2019-04-09 J-Lok Co. Pumpable resin system
US20210108514A1 (en) * 2017-10-27 2021-04-15 Epiroc Rock Drills Aktiebolag Method and system for ensuring the quality of a multi-component mixture for rock reinforcement
CN114622594A (zh) * 2022-03-09 2022-06-14 天津大学 一种模块化的筒型基础辅助沉放装置及入土沉放方法

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2767209C (en) * 2010-03-19 2013-08-13 Dywidag-Systems International Canada Ltd. A yielding spiral bolt appendage for a rock bolt
WO2015072828A1 (es) * 2013-11-15 2015-05-21 Aguilar Vera Oscar Octavio Ancla minera con rosca en punta
WO2015072837A1 (es) * 2013-11-15 2015-05-21 Aguilar Vera Oscar Octavio Ancla minera con rosca continua

Citations (2)

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Publication number Priority date Publication date Assignee Title
US3940941A (en) * 1973-04-02 1976-03-02 Acieries Reunies De Burbach-Eich-Dudelange S.A. Arbed Anchor bolts for mine roofs and method for installing same
US4098166A (en) * 1975-09-01 1978-07-04 Hilti Aktiengesellschaft Anchoring member secured by an adhesive material

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GB1271374A (en) * 1969-02-18 1972-04-19 Ici Ltd Improvements relating to anchor bolts and methods of installing same
GB1599918A (en) * 1978-05-31 1981-10-07 Exchem Holdings Grouting cartridge for rock-bolting
GB1599916A (en) * 1978-05-31 1981-10-07 Exchem Holdings Cementitious cartridge for rock-bolting
AU717939B2 (en) * 1996-12-23 2000-04-06 Dywidag-Systems International Pty. Limited Rock bolt with grout mixing device
DE10046804A1 (de) * 2000-09-18 2002-04-04 Erich Borgmeier Kombinierte Meißel- und Mischspitze für Fels- / Gebirgsanker
US20050039952A1 (en) * 2003-08-20 2005-02-24 Hill John L. Drilling apparatus, method, and system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3940941A (en) * 1973-04-02 1976-03-02 Acieries Reunies De Burbach-Eich-Dudelange S.A. Arbed Anchor bolts for mine roofs and method for installing same
US4098166A (en) * 1975-09-01 1978-07-04 Hilti Aktiengesellschaft Anchoring member secured by an adhesive material

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090290941A1 (en) * 2008-05-21 2009-11-26 Hilti Aktiengesellschaft Setting method for anchoring a fastening element
US7785041B2 (en) 2008-05-21 2010-08-31 Hilti Aktiengesellschaft Setting method for anchoring a fastening element
US20110033246A1 (en) * 2009-08-05 2011-02-10 F.M. Locotos Co., Inc. Tensionable tubular resin anchored tubular bolt and method
US8790044B2 (en) * 2009-08-05 2014-07-29 F. M. Locotos Co., Inc. Tensionable tubular resin anchored tubular bolt and method
US20120155970A1 (en) * 2010-12-15 2012-06-21 Fci Holdings Delaware, Inc. Mine Roof Bolt With End Fitting
US10954787B2 (en) 2015-03-03 2021-03-23 J-Lok Co. Pumpable two component resin
US10487655B2 (en) 2015-03-03 2019-11-26 J-Lok Co. Pumpable two component resin
WO2016141008A1 (en) * 2015-03-03 2016-09-09 J-Lok Co. Pumpable two component resin
US11506055B2 (en) 2015-03-03 2022-11-22 J-Lok Co. Pumpable resin system
US10253628B2 (en) 2016-09-02 2019-04-09 J-Lok Co. Pumpable resin system
US10669848B2 (en) 2016-09-02 2020-06-02 J-Lok Co. Pumpable resin system
US20210108514A1 (en) * 2017-10-27 2021-04-15 Epiroc Rock Drills Aktiebolag Method and system for ensuring the quality of a multi-component mixture for rock reinforcement
US11454115B2 (en) * 2017-10-27 2022-09-27 Epiroc Rock Drills Aktiebolag Method and system for ensuring the quality of a multi-component mixture for rock reinforcement
CN114622594A (zh) * 2022-03-09 2022-06-14 天津大学 一种模块化的筒型基础辅助沉放装置及入土沉放方法

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ZA200700740B (en) 2007-11-28
GB2434626A (en) 2007-08-01
AU2007200391A1 (en) 2007-08-16
PL381631A1 (pl) 2007-08-06
CA2576116A1 (en) 2007-07-31
CN101029571A (zh) 2007-09-05
GB0701799D0 (en) 2007-03-07
DE102007006277A1 (de) 2007-08-23
RU2007103541A (ru) 2008-08-10

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