Patent Publication Number: US-2023151575-A1

Title: Rapid construction device and method for prestressed basalt fiber anchor rod

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Chinese Patent Application No. 202111345981.X with a filing date of Nov. 15, 2021. The content of the aforementioned application, including any intervening amendments thereto, is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to the technical field of geotechnical engineering anchoring, in particular to a rapid construction device and method for a prestressed basalt fiber anchor rod. 
     BACKGROUND ART 
     As one of the main supporting forms of slope engineering, the anchor rod can effectively prevent the structural deformation and maintain the structural stability. A rock-soil anchoring structure of a common steel anchor rod mostly has the durability problem caused by steel bar corrosion, which brings potential safety hazards to a supporting structure. The basalt fiber reinforced plastic (BFRP) with the advantages of high tensile strength, desirable corrosion resistance, desirable stability, convenience in material obtaining, etc. is a good substitute of steel bars in the anchoring technology. As the BFRP has the features of weak shear strength and high tensile strength in mechanical properties, it is difficult to directly anchor and tension the BFRP. At the present stage, the BFRP is generally connected to a steel strand and other metal bar materials through a steel casing pipe connector at the end of the BFRP, and epoxy resin is poured into the connector casing pipe to prepare the composite bar material. The manufacturing and construction process of the basalt fiber anchor rod is complex and needs high technological requirements, so the rapid construction requirement is difficult to meet. 
     SUMMARY 
     In view of this, for solving the problem that the manufacturing and construction process of the basalt fiber anchor rod is complex and needs high technological requirements, such that the rapid construction requirement is difficult to meet, the embodiment of the present disclosure provides a rapid construction device and method for a prestressed basalt fiber anchor rod. 
     Embodiments of the present disclosure provide a rapid construction device for a prestressed basalt fiber anchor rod, including a drilling, bar-penetrating and grouting assembly, the drilling, bar-penetrating and grouting assembly includes a sleeve drill rod and a drill bit; 
     the sleeve drill rod includes a drill rod inner cylinder and a drill rod outer cylinder arranged around the drill rod inner cylinder; 
     a middle part of the drill bit is connected to a lower end of the drill rod inner cylinder, an edge of the drill is connected to a lower end of the drill rod outer cylinder, a constraint hole is defined in the middle part of the drill bit so as to allow a basalt fiber reinforced plastic (BFRP) penetrating the drill rod inner cylinder to penetrate, a magnetic baffle is arranged at a lower end of the constraint hole to shield the constraint hole, and a plurality of through holes are defined in a portion, between the drill rod inner cylinder and the drill rod outer cylinder, of the drill bit; and 
     the sleeve drill rod is configured to be connected to a drilling machine and driven by the drilling machine to drill and lift, during drilling to a set depth, the BFRP is pushed to push off the magnetic baffle to lower the BFRP to a set position, and during lifting, a space between the drill rod outer cylinder and the drill rod inner cylinder is grouted, and slurry falls below the drill bit via the through hole. 
     Further, a boss extending upwards is arranged in the middle part of the drill bit, and the constraint hole is a vertical via hole defined in the boss. 
     Further, a groove is defined in a position, located at the lower end of the constraint hole, of a lower portion of the boss so as to allow the magnetic baffle be embedded. 
     Further, the rapid construction device for a prestressed basalt fiber anchor rod includes an air blowing pump and a pressure pump, the air blowing pump is configured to blow air between the drill rod outer cylinder and the drill rod inner cylinder when the sleeve drill rod drills, and the pressure pump is used for grouting between the drill rod outer cylinder and the drill rod inner cylinder when the sleeve drill rod lifts. 
     Further, the rapid construction device for a prestressed basalt fiber anchor rod includes a prestress applying assembly which includes a leveling base plate supported at an opening of an anchor hole, a center hole jack arranged on the leveling base plate and a hydraulic extendable clamp arranged on the center hole jack, an upper end of the BFRP with the lower end anchored sequentially penetrates the center hole jack and the hydraulic extendable clamp, the hydraulic extendable clamp is configured to clamp the BFRP, and the center hole jack is configured to apply prestress to the BFRP. 
     Further, the hydraulic extendable clamp includes two steel ring beams oppositely arranged one above the other and an outer wrapping layer mounted between the two steel ring beams, the outer wrapping layer including a steel layer, a basalt fiber layer and a nylon fiber layer which are arranged from outside to inside sequentially, an oil injection cavity is defined in the steel layer, an oil inlet is defined in an outer wall of the steel layer, and a surface of the nylon fiber layer is roughened. 
     Further, the leveling base plate includes a top plate and a plurality of support legs connected to a bottom of the top plate, each of the support legs including an upper support leg and a lower support leg, the lower support leg is fixed at the opening of the anchor hole, an adjustment hole is defined in a lower end of the upper support leg, and an upper end of the lower support leg is connected to the adjustment hole in a fastened manner via a fastener. 
     Further, the rapid construction device for a prestressed basalt fiber anchor rod includes a hole plug anchor sealing assembly which includes a grouting baffle arranged at the opening of the anchor hole and a slurry baffle arranged in the anchor hole and distanced from the opening of the anchor hole with a set value, the BFRP sequentially penetrates the slurry baffle and the grouting baffle from bottom to top, an edge of the slurry baffle makes sealed contact with a wall of the anchor hole, a grouting pipe penetrates the grouting baffle, and the grouting pipe is used for grouting between the grouting baffle and the slurry baffle to form a concrete hole plug for locking the upper end of the BFRP. 
     Further, an outer seal ring sleeves the edge of the slurry baffle so as to press the wall of the anchor hole for sealing; and a bar bundle hole is defined in a middle part of the slurry baffle, and an inner seal ring is embedded in the bar bundle hole so as to allow the BFRP to penetrate and press the BFRP for sealing. 
     Embodiments of the present disclosure also provides a rapid construction method for a prestressed basalt fiber anchor rod, using the rapid construction device for a prestressed basalt fiber anchor rod, and including: 
     S1. connecting a sleeve drill rod to a drilling machine, and driving the sleeve drill rod by the drilling machine to drill to a set depth to form an anchor hole; 
     S2. pushing a BFRP downwards to make a magnetic baffle fall off, and then lowering the BFRP to a set position; and 
     S3. lifting the sleeve drill rod via rotation of the drilling machine, grouting a space between a drill rod outer cylinder and a drill rod inner cylinder, and making slurry fall below a drill bit via a through hole, so as to anchor a lower end of the BFRP via solidification of the slurry. 
     The technical solution defined in the embodiment of the present disclosure has the beneficial effects that in the rapid construction device and method for a prestressed basalt fiber anchor rod, a basalt fiber reinforced plastic (BFRP) is lowered in an anchor hole drilling process, the BFRP is lowered to a preset anchoring position, meanwhile, grouting is completed in a sleeve drill rod returning and lifting process, in the grouting process, the BFRP is constrained by a constraint hole to be kept at the preset position, drilling, bar-penetrating and grouting of an anchoring section are completed simultaneously, the defects that a traditional basalt fiber anchor rod construction process is complex and tedious can be overcome, construction may be completed rapidly and efficiently, guarantee is provided for safety of a supporting structure, and the construction efficiency of the basalt fiber anchor rod may be greatly improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of a rapid construction device for a prestressed basalt fiber anchor rod in the present disclosure; 
         FIG.  2    is a structural schematic diagram of a drilling, bar-penetrating and grouting assembly; 
         FIG.  3    is a structural schematic diagram of a drill bit  2  in  FIG.  2   ; 
         FIG.  4    is a bottom view of the drill bit  2  in  FIG.  2   ; 
         FIG.  5    is a sectional view of a sleeve drill rod  1  in  FIG.  2   ; 
         FIG.  6    is a structural schematic diagram a leveling base plate  5  in  FIG.  1   ; 
         FIG.  7    is a structural schematic diagram of a support leg  502  in  FIG.  6   ; 
         FIG.  8    is a structural schematic diagram of a hydraulic extendable clamp  7  in  FIG.  1   ; 
         FIG.  9    is a structural schematic diagram of a hole plug anchor sealing assembly; and 
         FIG.  10    is a structural schematic diagram of a slurry baffle  8  in  FIG.  1   . 
     
    
    
     In the figures:  1 —sleeve drill rod,  101 —drill rod outer cylinder,  102 —drill rod inner cylinder,  2 —drill bit,  201 —polycrystalline diamond compact (PDC) drill bit wall,  201   a —through hole,  202 —via hole wall,  202   a —boss,  202   b —magnetic baffle,  203 —metal cutting edge,  3 —anchor hole,  4 —basalt fiber reinforced plastic,  5 —leveling base plate,  501 —top plate,  502 —support leg,  502   a —upper support leg,  502   b —lower support leg,  502   c —adjustment bolt,  503 —angle gauge,  504 —expansion bolt,  6 —center hole jack,  7 —hydraulic extendable clamp,  701 —steel ring beam,  701   a —fixing screw rod,  702 —steel layer,  702   a —oil inlet,  703 —basalt fiber layer,  704 —nylon fiber layer,  8 —slurry baffle,  801 —outer seal ring,  802 —bar bundle hole,  803 —inner seal ring,  9 —grouting baffle,  901 —grouting pipe,  902 —exhaust port,  10 —anchoring section, and  11 —concrete hole plug. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In order to make the objective, technical solution and advantages of the present disclosure clearer, embodiments of the present disclosure will be further described in detail in conjunction with the accompanying drawings. The following describes a preferred one of a number of possible embodiments of the present disclosure, and is intended to provide a basic understanding of the present disclosure, but is not intended to identify key or critical elements of the present disclosure or to define the scope of protection. 
     In the description of the present disclosure, it should be noted that, unless otherwise clearly specified, meanings of terms “mount” and “connect” should be understood in a board sense. For example, the connection may be a fixed connection, a detachable connection, or an integral connection; may be a mechanical connection or an electrical connection; may be a direct connection or an indirect connection by using an intermediate medium; or may be intercommunication between two components. Those of ordinary skill in the art may understand specific meanings of the foregoing terms in the present disclosure based on a specific situation. 
     With reference to  FIGS.  1  and  2   , the embodiment of the present disclosure provides a rapid construction device for a prestressed basalt fiber anchor rod. The device includes a drilling, bar-penetrating and grouting assembly, a prestress applying assembly and a hole plug anchor sealing assembly. 
     As shown in  FIGS.  2  and  5   , the drilling, bar-penetrating and grouting assembly includes a sleeve drill rod  1  and a drill bit  2 . Specifically, the sleeve drill rod  1  includes a drill rod inner cylinder  102  and a drill rod outer cylinder  101  arranged around the drill rod inner cylinder  102 . The drill rod outer cylinder  101  and the drill rod inner cylinder  102  are both cylindrical and have coinciding axes, and threaded connectors are arranged at lower ends of the drill rod outer cylinder  101  and the drill rod inner cylinder  102 . 
     As shown in  FIGS.  2  and  3   , a middle part of the drill bit  2  is connected to the lower end of the drill rod inner cylinder  102 , and an edge of the drill bit  2  is connected to the lower end of the drill rod outer cylinder  101 . Specifically, the drill bit  2  is a polycrystalline diamond compact (PDC) drill bit, including a PDC drill bit wall  201 , a via hole wall  202  arranged in a middle part of the PDC drill bit wall  201 , and a plurality of convex metal cutting edges  203  arranged at a bottom of the PDC drill bit wall  201 . An edge of the PDC drill bit wall  201  is provided with a threaded connector and is connected to the threaded connector at the lower end of the drill rod outer cylinder  101  via the threaded connector. An upper end of the via hole wall  202  is provided with a threaded connector and is connected to the threaded connector at the lower end of the drill rod inner cylinder  102  via the threaded connector. In this way, the sleeve drill rod  1  is connected to the drill bit  2 . 
     As shown in  FIGS.  2  and  3   , a constraint hole is defined in the middle part of the drill bit  2  so as to allow a basalt fiber reinforced plastic (BFRP)  4  penetrating the drill rod inner cylinder  102  to penetrate. The constraint hole is defined in an axis of the via hole wall  202  and penetrates the via hole wall  202 . The BFRP  4  penetrating into the constraint hole is constrained by the constraint hole and kept on the axis of the drill rod inner cylinder  102 . 
     In addition, a magnetic baffle  202   b  is arranged at a lower end of the constraint hole to shield the constraint hole, and the magnetic baffle  202   b  is used for blocking the lower end of the constraint hole so as to prevent the BFRP  4  from falling into the bottom of the hole in a drilling process, and further to prevent drilling cuttings from entering the drill rod inner cylinder  102 . In this embodiment, a boss  202   a  extending upwards is arranged in the middle part of the drill bit  2 , the boss  202   a  is located at a lower end of the via hole wall  202 , and the constraint hole is a vertical via hole defined in the boss  202   a.  A groove is defined in a position, located at the lower end of the constraint hole, of a lower portion of the boss  202   a  so as to allow the magnetic baffle  202   b  to be embedded, and the magnetic baffle  202   b  abuts against the lower end of the BFRP  4  penetrating the constraint hole. 
     As shown in  FIG.  4   , a plurality of through holes  201   a  are defined in a portion, between the drill rod inner cylinder  102  and the drill rod outer cylinder  101 , of the drill bit  2 . The through holes  201   a  are provided at the bottom of the PDC drill bit wall  201 , in particular evenly distributed between the metal cutting edges  203 . The through hole  201   a  is in communication with a space above and below the drill bit  2 , such that airflow or slurry may flow from above to below the drill bit. 
     The drilling, bar-penetrating and grouting assembly further includes an air blowing pump and a pressure pump. The drilling, bar-penetrating and grouting assembly is used for drilling, bar-penetrating and grouting. Specifically, the sleeve drill rod  1  is connected to a drilling machine and driven by the drilling machine to drill and lift. During drilling, the sleeve drill rod  1  drills to a set depth to form an anchor hole, in the drilling process, air is blown between the drill rod outer cylinder  101  and the drill rod inner cylinder  102  via the air blowing pump, the airflow is blown out from the through hole, and drilling cuttings are blown out. During bar penetrating, the BFRP  4  is pushed to push off the magnetic baffle  202   b,  such that the BFRP  4  is lowered to a set position. During grouting, the sleeve drill rod  1  is lifted via rotation of the drilling machine, a space between the drill rod outer cylinder  101  and the drill rod inner cylinder  102  is grouted by using the pressure pump, and slurry falls below the drill bit  2  via the through hole  201   a,  so as to anchor the lower end of the BFRP  4  via solidification of the slurry. 
     As shown in  FIGS.  1  and  6   , the prestress applying assembly includes a leveling base plate  5  supported at an opening of the anchor hole, a center hole jack  6  arranged on the leveling base plate  5  and a hydraulic extendable clamp  7  arranged on the center hole jack  6 . An upper end of the BFRP  4  with the lower end anchored sequentially penetrates the center hole jack  6  and the hydraulic extendable clamp  7 , the hydraulic extendable clamp  7  is configured to clamp the BFRP  4 , and the center hole jack  6  is configured to apply prestress to the BFRP  4 . 
     As shown in  FIG.  6   , the leveling base plate  5  includes a top plate  501  and a plurality of support legs  502  connected to a bottom of the top plate  501 , each of the support legs  502  including an upper support leg  502   a  and a lower support leg  502   b,  the lower support leg  502   b  is fixed at the opening of the anchor hole  3 , an adjustment hole is defined in a lower end of the upper support leg  502   a,  and an upper end of the lower support leg  502   b  is connected to the adjustment hole in a fastened manner via a fastener. 
     Specifically, the lower support leg  502   b  is fixed to the opening of the anchor hole  3  via an expansion bolt  504 , the expansion bolt  504  being mounted to an earth surface where the opening of the anchor hole  3  is located. The lower support leg  502   b  is L-shaped and is connected to the expansion bolt  504  in a fastened manner. 
     As shown in  FIG.  7   , the fastener is an adjustment bolt  502   c,  and there may be a plurality of fasteners, and the plurality of adjustment bolts  502   c  penetrate the upper end of the lower support leg  502   b  and the adjustment hole to connect the upper support leg  502   a  to the lower support leg  502   b  in a fastened manner. The adjustment hole may slide up and down to a proper mounting position and then is fastened in the fastening process of the adjustment bolt  502   c,  so as to adjust a height of each of the support legs  502 , and the top plate  501  is perpendicular to an axis direction of the BFRP  4 . In addition, an angle gauge  503  may be arranged on the top plate  501  to match the support leg  502  for leveling, and it may be guaranteed that when the opening of the anchor hole  3  is uneven, the top plate  501  is leveled to be perpendicular to the axis direction of the BFRP  4 . 
     As shown in  FIGS.  1  and  8   , the hydraulic extendable clamp  7  is fixed to the center hole jack  6  and includes two steel ring beams  701  oppositely arranged one above the other and an outer wrapping layer mounted between the two steel ring beams  701 , the outer wrapping layer including a steel layer  702 , a basalt fiber layer  703  and a nylon fiber layer  704  which are arranged from outside to inside sequentially, an oil injection cavity is defined in the steel layer  702 , an oil inlet  702   a  is defined in an outer wall of the steel layer  702 . 
     An upper top face and a lower top face of the steel layer  702  are provided with a plurality of sets of inwards-concave threaded concave holes, the steel ring beam  701  is provided with a plurality of via holes, the via holes correspond one-to-one to the threaded concave holes, and fixing screw rods  701   a  penetrate the via holes respectively so as to connect the via holes to the corresponding threaded concave holes. In this way, an upper end and a lower end of the steel layer  702  are fixedly connected to the two steel ring beams  701  respectively. The steel layer  702  may only press the BFRP  4  inwards under the action of oil pressure, and an inner surface of the nylon fiber layer  704  needs to be roughened to increase static friction between the nylon fiber layer  704  and the BFRP  4 . 
     As shown in  FIGS.  1  and  9   , a hole plug anchor sealing assembly includes a grouting baffle  9  arranged at the opening of the anchor hole  3  and a slurry baffle  8  arranged in the anchor hole  3  and distanced from the opening of the anchor hole  3  with a set value, the BFRP  4  sequentially penetrates the slurry baffle  8  and the grouting baffle  9  from bottom to top, an edge of the slurry baffle  8  makes sealed contact with a wall of the anchor hole  3 , and a grouting pipe  901  and an exhaust port  902  penetrate the grouting baffle  9 . 
     As shown in  FIG.  10   , an outer seal ring  801  sleeves the edge of the slurry baffle  8  so as to press the wall of the anchor hole  3  for sealing; and a bar bundle hole  802  is defined in a middle part of the slurry baffle  8 , and an inner seal ring  803  is embedded in the bar bundle hole  802  so as to allow the BFRP  4  to penetrate and press the BFRP  4  for sealing. 
     After the center hole jack  6  applies the prestress to the BFRP  4 , the grouting pipe  901  is used for grouting between the grouting baffle  9  and the slurry baffle  8  to form a concrete hole plug  11  for locking the upper end of the BFRP  4 . 
     In addition, as shown in  FIGS.  1 - 10   , based on the rapid construction device for a prestressed basalt fiber anchor rod, the embodiment of the present disclosure further provides a rapid construction method for a prestressed basalt fiber anchor rod. The method includes: 
     S1. connect a sleeve drill rod  1  to a drilling machine, drive the sleeve drill rod  1  by the drilling machine to drill to a set depth to form an anchor hole  3 , and blow air between a drill rod outer cylinder  101  and a drill rod inner cylinder  102  via an air blowing pump in a drilling process, so as to blow drilling cuttings out of a gap between the drill rod outer cylinder  101  and the anchor hole  3 ; 
     S2. push a BFRP  4  downwards to make a magnetic baffle  202   b  fall off, and then lowering the BFRP  4  to a set position; and 
     S3. lift the sleeve drill rod  1  via rotation of the drilling machine, grout a space between the drill rod outer cylinder  101  and the drill rod inner cylinder  102  via a pressure pump, and make slurry fall below a drill bit  2  via a through hole  201   a,  so as to anchor a lower end of the BFRP  4  via solidification of the grout to form an anchoring section  10 . In a lifting process of the sleeve drill rod  1 , the BFRP  4  is constrained by a constraint hole to be kept at a set position, so as to anchor the BFRP  4  at the preset position. 
     Then slurry for an anchoring section  10  is maintained, after the slurry is solidified to reach designed strength, the BFRP  4  sequentially penetrates a slurry baffle  8  and a grouting baffle  9  from bottom to top, and the slurry baffle  8  and the grouting baffle  9  are mount at designed positions respectively. Then, a leveling base plate  5  is mounted at an opening of the anchor hole  3 , a center hole jack  6  and a hydraulic extendable clamp  7  are mounted on an upper portion of the leveling base plate  5  sequentially, and the BFRP  4  penetrates the center hole jack  6  and the hydraulic extendable clamp  7  sequentially. 
     The BFRP  4  is then pre-stressed: a confining pressure value of the hydraulic extendable clamp  7  is set according to a design value of tensile strength of the basalt fiber anchor rod and a peripheral area of the BFRP  4 , and the oil inlet amount of an oil inlet is adjusted to make the hydraulic extendable clamp  7  tightly hold the gripped BFRP. The center hole jack  6  is opened to integrally tension the BFRP  4 . When the BFRP  4  is tensioned to a designed prestress value, the center hole jack  6  is locked. 
     Finally, anchor sealing treatment is performed on the BFRP  4 : early-strength micro-expansion concrete slurry is injected into a space between the slurry baffle  8  and the grouting baffle  9  via a grouting pipe  901 , and grouting is stopped until the injected early-strength micro-expansion concrete slurry overflows from an exhaust port  902 . After the strength of the early-strength micro-expansion concrete reaches lockable strength, the center hole jack  6  and the hydraulic extendable clamp  7  are closed, and the hydraulic extendable clamp  7 , the center hole jack  6 , the leveling base plate  5  and the grouting baffle  9  are sequentially taken down. The BFRP is cut along an upper surface of a concrete hole plug  11 , such that simple and rapid anchor sealing treatment is achieved. 
     Herein, the involved orientation terms such as “front”, “rear”, “upper”, and “lower” are defined in terms of the positions of parts and between the parts in the drawings, which are used just for clarity and convenience of expressing the technical solution. It should be understood that they are relative concepts and may vary accordingly according to different ways of use and placement, and the use of such parties should not limit the scope of protection of the claimed application. 
     The above examples and the features in the examples herein may be combined with each other in a non-conflicting situation. 
     The above descriptions are merely preferred examples of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, and the like made within the spirit and principle of the present disclosure shall be all included in the protection scope of the present disclosure.