CN115898497A - High-pressure grouting end anchor type self-drilling prestressed anchor rod and construction method thereof - Google Patents

Abstract

The invention discloses a high-pressure grouting end anchor type self-drilling prestressed anchor rod which comprises a drill bit, an anchoring material, a hollow rod body, a grouting controller and a grouting mixer, wherein the drill bit is connected to the end part of an anchoring section of the hollow rod body, the grouting controller is installed on the hollow rod body, two end parts of the grouting controller are respectively connected with the hollow rod body, the grouting mixer is communicated with the end part of the free end of the hollow rod body, a grouting channel is arranged inside the hollow rod body, the anchoring material is uniformly stirred in the grouting mixer, and the anchoring material is injected through the grouting channel of the hollow rod body. The high-pressure grouting end-anchored self-drilling pre-stressed anchor rod has high anchoring force and good timeliness, and the arrangement of the grouting controller ensures that the anchoring material is grouted to be compact and uniformly wrap the rod body, so that the anchoring force is greatly improved; the problem of among the prior art in the anchor section slip casting have slip casting not full, not closely knit, with the poor scheduling phenomenon of pore wall cohesiveness, lead to anchor power very low, the timeliness is poor, can't exert prestressing force at once is solved.

Description

High-pressure grouting end anchor type self-drilling prestressed anchor rod and construction method thereof

Technical Field

The invention belongs to the technical field of tunnel engineering, and particularly relates to a high-pressure grouting end-anchored self-drilling pre-stressed anchor rod and a construction method thereof.

Background

When the anchor rod is applied to a weak and loose surrounding rock stratum, a surrounding rock drilled hole is easy to collapse, and a self-advancing anchor rod is mostly adopted.

Firstly, due to poor integrity of the hole wall, low surrounding rock strength and slow solidification of a cement-based anchoring material matched with a self-propelled anchor rod, the problems of insufficient grouting, incompact grouting, poor cohesiveness with the hole wall and the like of the grouting of an anchoring section exist, so that the anchoring force is very low, the timeliness is poor and the prestress cannot be applied immediately.

Secondly, the traditional anchor rod adopts the mode of screwing up the nut and extrudeing the backing plate to exert prestressing force, and when the screw thread machining precision of nut or the body of rod is not high and the backing plate slope, the nut takes place the auto-lock phenomenon because of eccentric atress, leads to the nut to be difficult to be twisted, and then causes and can not extrude the backing plate and exert prestressing force or mistake and regard as the prestressing force to exert the wrong condition that targets in place.

Finally, the tunnel in the weak loose stratum is easy to deform greatly, the anchor rod fails locally, and due to the fact that the anchor rod and the anchor rod are weak in relation, the anchor rod and the anchor rod cannot be stressed cooperatively, and then the anchor rod fails wholly.

In conclusion, the existing anchor rod is difficult to meet the requirements of instant support, strong support and comprehensive support of the weak surrounding rock tunnel.

Through search and discovery, a Chinese utility model with the patent number CN201820737228, which is published on the days 2019-02-19, discloses a grouting anchoring self-drilling prestressed anchor rod device for a soft rock roadway, which comprises a nut tray, a tail rod body and an end steel pipe rod body, wherein the tail rod body is connected with the nut tray, and the middle part of the tail rod body is provided with a grouting hole; the end part steel pipe rod body is provided with a slurry overflow hole and a conical tip; a rod body threaded connection section is arranged between the tail rod body and the end steel pipe rod body; an anchor bolt thread section is arranged between the nut tray and the tail rod body; and the end steel pipe body is provided with an anchor rod anchoring section. The above technical problems cannot be solved.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a high-pressure grouting end anchor type self-drilling prestressed anchor rod which is simple in structure and convenient to use, has high anchoring force and good timeliness, and the arrangement of a grouting controller ensures that an anchoring material is grouted to be compact and uniformly wrap a rod body, so that the anchoring force is greatly improved; the invention also provides a construction method of the high-pressure grouting end anchor type self-drilling prestressed anchor rod.

In order to realize the purpose, the technical scheme of the invention is as follows: the utility model provides a high pressure grout end anchor formula is from boring prestressed anchorage pole, includes drill bit, anchor material, the cavity body of rod, slip casting controller and slip casting blender, the tip at cavity body of rod anchor section is connected to the drill bit, and the slip casting controller is installed on the cavity body of rod, and the both ends of slip casting controller are connected with the cavity body of rod respectively, and the tip intercommunication of slip casting blender and cavity body of rod free end, the inside slip casting passageway that is equipped with of the cavity body of rod, anchor material stir in the slip casting blender is even, and anchor material pours into through the slip casting passageway of the cavity body of rod.

Further, the anchoring material is an A and B two-component material which is mixed according to a certain proportion, after the anchoring material overflows from the drill bit, high-pressure grouting is carried out in a closed space of the anchoring section and the anchoring material permeates into cracks of the hole wall, the anchoring material can be solidified within 30-120 seconds, and the end part of the anchor rod is rapidly anchored.

Furthermore, the hollow rod body is made of high-elongation steel, the outer surface of the hollow rod body is provided with a left-handed or right-handed standard waveform thread, and the inside of the hollow rod body is of a hollow structure and serves as a grouting channel.

Further, slip casting controller includes hollow core pipe and shell, and the both ends of hollow core pipe all are connected with the cavity body of rod respectively through standard wave form internal thread, and the shell parcel is in the outside of hollow core pipe, and metal fastening ring sealing connection is passed through at the both ends of shell and hollow core pipe.

Furthermore, a closed space is formed between the outer wall of the hollow core pipe and the inner wall of the shell, a water absorption material is preset in the closed space, and the middle of the hollow core pipe is provided with slurry outlet holes of the check valves which are symmetrically distributed.

Furthermore, the grouting controller connects the two sections of hollow rod bodies to form a grouting channel, grout flows into the shell from a grout outlet hole of the check valve on the hollow core pipe during grouting, the shell expands to completely block the drilled hole, a closed space is formed in the anchoring section, and the anchor rod is centered in the drilled hole after the grouting controller expands.

Furthermore, the stock still includes spacing backing plate, and spacing backing plate is the toper backing plate, and the central circular hole department of spacing backing plate is equipped with the round stopping tooth, and stopping tooth and the inseparable interlock of cavity body of rod surface wave form screw thread can only advance on the cavity body of rod and can not retreat.

Furthermore, one corner of each limiting base plate is tilted and provided with a through hole, and the high-strength steel strand sequentially penetrates through the through holes of the limiting base plates to connect the anchor rods to form integral stress.

Further, the stock still includes and ends the thick liquid stopper, ends the thick liquid stopper and sets up the free end at the cavity body of rod, ends thick liquid stopper and is located the place ahead of spacing backing plate.

The invention also relates to a construction method of the high-pressure grouting end anchor type self-drilling pre-stressed anchor rod, based on the high-pressure grouting end anchor type self-drilling pre-stressed anchor rod, the construction method comprises the following steps:

step 1, construction preparation: preparing a jumbolter, a grouting system, a rod body and accessories, anchoring materials and high-pressure air/water working conditions required by anchor rod construction;

step 2, drilling and cleaning: and connecting the assembled anchor rod with an anchor rod drilling machine, starting the drilling machine to drive the rod body to rotate, and cutting the surrounding rock by the drill bit to drill holes. When the drilling depth is reached to the designed depth, connecting a high-pressure air/water pipe, and cleaning the drilled hole through high-pressure air/water;

step 3, firstly, applying axial force to the anchor rod to enable the drill bit of the anchor rod to be propped against the surrounding rock at the bottom of the hole; secondly, according to the different types of the grouting controllers, the shell of the grouting controller is expanded to plug the drilled hole in different modes;

and 4, end anchor high-pressure grouting: two feeding pipes of the high-pressure grouting pump are respectively arranged in two storage tanks for storing components A and B of the anchoring materials, and the grouting pipes are connected with the hollow rod body for high-pressure grouting;

step 5, prestress application: installing a limit base plate on the rod body, tensioning the hollow rod body by using an anchor rod installation tool, continuously pushing the limit base plate forwards to enable the limit base plate to be tightly pressed on the surface of the surrounding rock, loosening the hollow rod body when the tensioning force meets the requirement, and installing a nut behind the limit base plate;

step 6, after all anchor rods are installed, connecting limiting base plates at key positions of the anchor rods to form a net by using high-strength steel strands;

step 7, grouting after the anchor rod: when the anchor rod needs to be further protected, the grouting pipe can be inserted into the limiting base plate and the grout stopping plug through the reserved small hole, and cement grout grouting is conducted on the free end of the hollow anchor rod.

The technical scheme adopted by the invention has the advantages that:

1. the grouting controller can ensure that the anchoring material is grouted to be compact and uniformly wrap the rod body on the premise of not influencing the drilling, hole cleaning and stress of the anchor rod, thereby greatly improving the anchoring force. The method comprises the following specific steps: (1) the grouting controller can connect the two sections of hollow rod bodies to form a grouting channel together, so that the tension of the anchor rod is effectively transmitted, and the drilling, slag discharging and hole cleaning of the anchor rod are not influenced; (2) the grouting controller can expand at the initial stage of grouting to completely block the drilled hole and form a closed space in the anchoring section, so that anchoring materials are prevented from flowing, the materials are saved, and the anchoring section can be subjected to high-pressure grouting to improve grouting fullness and compactness. (3) After the grouting controller expands, the anchor rod can be centered in the drilled hole, so that the problems of insufficient annular thickness of an anchoring material and the like when the rod body contacts the hole wall are solved; (4) when the anchor rod at the top of the tunnel is installed, the anchor rod can be temporarily fixed in a drilled hole after the grouting controller expands, the anchor rod cannot slide out or fall off, and extra manual work or mechanical temporary support is avoided during construction.

2. The high-pressure grouting end-anchored self-drilling pre-stressed anchor rod uses the A and B two-component anchoring materials, and the anchoring materials can be solidified within 30-120 seconds, so that the end part of the anchor rod is quickly anchored; the limiting base plate is provided with stopping teeth, and the hollow rod body can only move forward but can not move backward. Therefore, during construction, only the limiting base plate is required to be abutted against the surface of the surrounding rock and the hollow rod body is pulled outwards, so that prestress can be applied, the operation is simple, and the prestress value is clear; the high-strength steel strand connects a plurality of anchor rods to form a collaborative stress structure, and the failure of the integral group anchor support caused by the failure of local anchor rods is avoided.

Drawings

FIG. 1 is a schematic diagram of a high-pressure grouting end-anchored self-drilling pre-stressed anchor rod before grouting and anchoring;

FIG. 2 is a schematic diagram of the high-pressure grouting end-anchored self-drilling prestressed anchor rod of the present invention after grouting and anchoring;

FIG. 3 is a schematic diagram of a grouting controller according to the present invention before expansion;

FIG. 4 is a schematic structural view of the grouting controller according to the present invention after expansion;

FIG. 5 is a schematic view of the installation of the grout stop plug of the present invention on the anchor rod;

FIG. 6 is a schematic view of the mounting structure of the limiting shim plate according to the present invention;

fig. 7 is a schematic view of multiple anchor rods connected together in accordance with the present invention.

In the figure: 1. a drill bit; 2. an anchoring material; 3. a hollow rod body; 4. a grouting controller; 41. a hollow core tube; 42. a housing; 43. a metal fastening ring; 44. a closed space; 45. a one-way valve pulp outlet hole; 5. an anti-corrosion sleeve; 6. connecting sleeves; 7. a grout stopping plug; 8. a limiting base plate; 81. stopping teeth; 82. a through hole; 9. a nut; 10. high-strength steel strands; 11. and (4) a grouting mixer.

Detailed Description

In the present invention, it is to be understood that the term "length"; "Width"; "Up"; "Down"; "front"; "Back"; "left"; "Right"; "vertical"; "horizontal"; "Top"; "bottom" "inner"; "outer"; "clockwise"; "counterclockwise"; "axial"; "planar direction"; "circumferential" and the like indicate orientations or positional relationships that are based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the indicated device or element must have a particular orientation; constructed and operative in a particular orientation and therefore should not be construed as limiting the invention.

As shown in fig. 1, a high-pressure grouting end anchor type self-drilling prestressed anchor rod comprises a drill bit 1, an anchoring material 2, a hollow rod body 3, a grouting controller 4 and a grouting mixer 11, wherein the drill bit 1 is connected to the end part of the anchoring section of the hollow rod body 3, the grouting controller 4 is installed on the hollow rod body 3, two end parts of the grouting controller 4 are respectively connected with the hollow rod body 3, the grouting mixer 11 is communicated with the end part of the free end of the hollow rod body 3, a grouting channel is arranged inside the hollow rod body 3, the anchoring material 2 is uniformly stirred in the grouting mixer 11, and the anchoring material 2 is injected through the grouting channel of the hollow rod body 3. The high-pressure grouting end-anchored self-drilling pre-stressed anchor rod has high anchoring force and good timeliness, and the arrangement of the grouting controller ensures that the anchoring material is grouted to be compact and uniformly wrap the rod body, so that the anchoring force is greatly improved; the problem of among the prior art in the anchor section slip casting have slip casting not full, not closely knit, with the poor scheduling phenomenon of pore wall cohesiveness, lead to anchor power very low, the timeliness is poor, can't exert prestressing force at once is solved.

The drill bit 1 is a disposable drill bit and mainly has the functions of cutting surrounding rock and forming a hole; the drill bit is provided with small holes, and high-pressure air and high-pressure water can be blown to discharge slag and clear holes and also discharge slurry.

The anchoring material 2 is a A and B double-component material which are mixed according to a certain proportion, after the anchoring material 2 overflows from the drill bit 1, high-pressure grouting is carried out in a closed space of the anchoring section and the anchoring material permeates into cracks of the hole wall, the anchoring material 2 can be solidified within 30-120 seconds, and the end part of the anchor rod is rapidly anchored.

Preferably, the anchoring material is a silicate modified polyurethane grouting material, and comprises two components, namely AB, black material and white material. Wherein the component A comprises polyether polyol, sodium silicate, a catalyst, a flame retardant, an antistatic agent and the like, and the component B comprises polymethylene polyphenyl polyisocyanate, polymeric MDI, a thixotropic agent and the like; the mixing ratio of the component A material to the component B material is 1.

Specifically, the anchoring material 2 is divided into a component A and a component B, and is uniformly stirred by the grouting mixer 11 according to a certain proportion and then injected through the inner wall of the hollow rod body 3. And after the anchoring material 2 overflows from the drill bit 1, performing high-pressure grouting in the closed space of the anchoring section, permeating into cracks of the hole wall, and solidifying within 30-120 seconds, thereby realizing the rapid anchoring of the end part of the anchor rod.

The hollow rod body 3 is made of high-elongation steel and can be extended to prevent the hollow rod body from being broken when tunnel surrounding rocks are greatly deformed. The outer surface of the hollow rod body 3 is provided with standard left-handed or right-handed corrugated threads, and the inside of the hollow rod body 3 is of a hollow structure and serves as a grouting channel.

The grouting controller 4 comprises a hollow core tube 41 and a shell 42, wherein two ends of the hollow core tube 41 are respectively connected with the hollow rod body 3 through standard wave-shaped internal threads, the shell 42 wraps the outside of the hollow core tube 41, and two end parts of the shell 42 and the hollow core tube 41 are hermetically connected through a metal fastening ring 43. A closed space 44 is formed between the outer wall of the hollow core tube 41 and the inner wall of the shell 42, a water-absorbing material is preset in the closed space 44, and the middle part of the hollow core tube 41 is provided with symmetrically distributed one-way valve pulp outlet holes 45. The opening pressure of the one-way valve grout outlet 45 is higher than the air pressure and the water pressure when the anchor rod drills. The grouting controller 4 connects the two sections of hollow rod bodies 3 to form a grouting channel, grout flows into the shell 42 from the one-way valve grout outlet 45 on the hollow core pipe 41 during grouting, the shell 42 expands to completely block a drilled hole, a closed space is formed in the anchoring section, and the anchor rod is centered in the drilled hole after the grouting controller expands.

According to the expansion principle of the grouting controller 4, the following three types can be distinguished: (1) grouting (water) expansion type: the casing 42 is made of flexible material, and slurry (water) can enter the closed space 44 through the slurry outlet hole 45 of the one-way valve under certain pressure. The slurry (water) is injected but not discharged, causing the casing 42 to expand outwardly, thereby acting to seal the borehole. (2) Reaction expansion type: the housing 42 is made of a flexible material, and water-absorbent materials such as water-absorbent resin, water-swellable rubber, and foamed polyurethane are pre-disposed in the closed space 44. Water under certain pressure can enter the closed space 44 through the slurry outlet hole 45 of the one-way valve, the water-absorbing material can quickly react when meeting water, and the volume can be expanded by over 600 percent, so that the drilled hole can be blocked after the flexible shell 42 is expanded. (3) Steel expansion shell type: the housing 42 is folded from steel. Under ultrahigh pressure, slurry (water) enters the closed space 44 to irreversibly extend and expand the steel shell 42, so that the drilling plugging effect is achieved. At this time, the steel shell 42 maintains its expanded shape even if the grouting (water) pressure is further reduced. (4) When the anchor rod at the top of the tunnel is installed, the anchor rod can be temporarily fixed in a drilled hole after the grouting controller expands, the anchor rod cannot slide out or fall off, and extra manual work or mechanical temporary support is avoided during construction.

The grouting controller ensures that the anchoring material is grouted to be compact and uniformly wrap the rod body on the premise of not influencing the drilling, hole cleaning and stress of the anchor rod, thereby greatly improving the anchoring force. The method comprises the following specific steps: (1) the grouting controller can connect the two sections of hollow rod bodies 3 to form a grouting channel together, so that the tension of the anchor rod is effectively transmitted, and the drilling, slag discharge and hole cleaning of the anchor rod are not influenced; (2) the grouting controller can expand in the initial grouting stage to completely block the drilled hole, and a closed space is formed in the anchoring section, so that the anchoring material is prevented from flowing, the material is saved, and the anchoring section can perform high-pressure grouting to improve grouting fullness and compactness. (3) The anchor rod can be centered in the drilled hole after the grouting controller expands, and the problems that the annular thickness of an anchoring material is insufficient when the rod body contacts the hole wall and the like are avoided.

The outer surface of the hollow rod body 3 on the right side of the grouting controller is wrapped with an anti-corrosion sleeve 5 which mainly acts for preventing the anchor rod body from being corroded; and secondly, characters or bar code information such as the type specification, batch and application project name of the anchor rod is printed on the surface of the anti-corrosion sleeve, so that the whole process of the outgoing anchor rod is traced.

The high-pressure grouting end anchor type self-drilling prestressed anchor rod further comprises a connecting sleeve 6 and a grout stop plug 7, wherein the connecting sleeve 6 is used for connecting two rod bodies and plays a role in lengthening; the grout stop plug 7 is arranged at the free end of the hollow rod body 3, and the grout stop plug 7 is positioned in front of the limit backing plate 8; when the free section of the anchor rod needs to further improve the durability or the full-length anchoring force of the anchor rod, the free section can be injected with post-grouting materials such as cement paste and polyurethane, and the grout stop plug 7 can prevent grout from overflowing from the hole opening.

This high pressure grout end anchor formula is from boring prestressed anchorage pole still includes spacing backing plate 8, and spacing backing plate 8 is the toper backing plate, and the central round hole department of spacing backing plate 8 is equipped with round stopping tooth 81, and stopping tooth 81 and the inseparable interlock of 3 surface wave form threads of the cavity body of rod, spacing backing plate 8 can only advance on the cavity body of rod 3 can not retreat. One corner of the limiting base plate 8 is tilted and provided with a through hole 82, and the high-strength steel strand 10 sequentially penetrates through the through holes 82 of the limiting base plates 8 to connect a plurality of anchor rods to form integral stress.

Specifically, the limiting base plate 8 is a conical base plate, a circle of stopping teeth are arranged in a central circular hole of the conical base plate, and the diameter of the circular hole is slightly smaller than the outer diameter of the hollow rod body 3. The stopping teeth are tightly meshed with the wave-shaped threads on the outer surface of the hollow rod body 3, and the limiting cushion plate 8 only can move forwards but not can move backwards on the hollow rod body under the action of extrusion force and frictional resistance. And one corner of the backing plate is tilted and provided with a through hole, so that the high-strength steel strand 10 can pass through. The steel strand 10 can pass through the through holes of a plurality of backing plates in proper order, and the multiple stock is connected and is formed whole atress, avoids leading to whole inefficacy because of the individual stock became invalid.

Benefiting from the stopping tooth, the limiting base plate 8 is only required to be abutted to the surface of the surrounding rock and to be pulled outwards to draw the hollow rod body 2, and the rod body prestress application is completed by stopping the pulling after the pulling force reaches the design requirement. The tension type prestress applying method avoids the problems that the nut is not screwed and cannot be screwed tightly, and the like, and meanwhile, the prestress applying value of the rod body can be directly measured in the construction process without converting the axial force through torque.

And a nut 9 is arranged behind the limiting cushion plate 8 on the hollow rod body 3, and after the prestress of the anchor rod is applied, the nut 9 is screwed down to prevent the stopping teeth of the limiting cushion plate 8 from losing efficacy.

The high-pressure grouting end-anchored self-drilling prestressed anchor rod uses the A and B bi-component anchoring materials, and the anchoring materials can be solidified within 30-120 seconds, so that the end part of the anchor rod is quickly anchored; the limiting base plate is provided with stopping teeth, and the hollow rod body can only move forward but can not move backward. Therefore, during construction, only the limiting base plate 8 is required to be abutted against the surface of the surrounding rock and the hollow rod body 3 is required to be pulled outwards, so that prestress can be applied, the operation is simple, and the prestress value is clear; the high-strength steel strand connects a plurality of anchor rods to form a collaborative stress structure, and the failure of the integral group anchor support caused by the failure of local anchor rods is avoided.

The grouting controller can ensure that the anchoring material is grouted to be compact and uniformly wrap the rod body on the premise of not influencing the drilling, hole cleaning and stress of the anchor rod, thereby greatly improving the anchoring force. The method comprises the following specific steps: (1) the grouting controller can connect the two sections of hollow rod bodies to form a grouting channel together, so that the tension of the anchor rod is effectively transmitted, and the drilling, slag discharge and hole cleaning of the anchor rod are not influenced; (2) the grouting controller can expand in the initial grouting stage to completely block the drilled hole, and a closed space is formed in the anchoring section, so that the anchoring material is prevented from flowing, the material is saved, and the anchoring section can perform high-pressure grouting to improve grouting fullness and compactness. (3) The anchor rod can be centered in the drilled hole after the grouting controller expands, and the problems that the annular thickness of an anchoring material is insufficient when the rod body contacts the hole wall and the like are avoided.

Based on the high-pressure grouting end anchor type self-drilling prestressed anchor rod, the invention also relates to a construction method of the high-pressure grouting end anchor type self-drilling prestressed anchor rod, which comprises the following steps:

step 1, construction preparation. And preparing working conditions of an anchor rod drilling machine, a grouting system, a rod body and accessories, anchoring materials, high-pressure air (water) and the like required by anchor rod construction.

And 2, drilling and cleaning the hole. And connecting the assembled anchor rod with an anchor rod drilling machine, starting the drilling machine to drive the rod body to rotate, and cutting the surrounding rock by the drill bit to drill holes. When the drilling machine is rotated to the designed depth, the high-pressure air (water) pipe is connected, and the drilled hole is cleaned through the high-pressure air (water).

And 3, firstly, applying axial force to the anchor rod to enable the drill bit of the anchor rod to be propped against the surrounding rock at the bottom of the hole. And secondly, according to different types of grouting controllers, expanding the shell of the grouting controller to plug the drilled hole in different modes. Aiming at the grouting (water) expansion type, the air pressure or the water pressure can be improved, so that the grouting (water) expansion type is inflated (liquid) by the grouting (water) expansion type. Or the high-pressure air (water) pipe can be removed and connected with a grouting pipe, and the anchoring material slurry is injected under high pressure to fill and expand the liquid. For reactive expansion, the water pressure is increased to make the contents react and expand when meeting water. For the steel expansion shell mold, high pressure water or high pressure grouting can be used for expanding the steel expansion shell mold. Finally, after the pressure is stabilized for a period of time at a specific pressure, the water, wind or grout stops being injected, and the anchor cannot be easily pulled out, and the grouting controller is considered to have been expanded.

And 4, performing high-pressure grouting on the end anchor. Two feeding pipes of the high-pressure grouting pump are respectively arranged in two storage tanks for storing components A and B of the anchoring materials, and the grouting pipes are connected with the hollow rod body for high-pressure grouting. In the process, grouting parameters are comprehensively determined according to chemical components of the surrounding rock, structural surface characteristics and the like, so that the uniformly mixed anchoring material fixes the anchoring section of the anchor rod in the surrounding rock. The rod body is not shaken in a short time after grouting.

And 5, applying prestress. And installing the limiting base plate on the hollow rod body, tensioning the hollow rod body by using an anchor rod installation tool, and continuously pushing the limiting base plate forwards to enable the limiting base plate to be tightly pressed on the surface of the surrounding rock. When the tensile force meets the requirement, the hollow rod body is loosened, and a nut is installed behind the limiting base plate.

And step six 6, after all the anchor rods are installed, connecting the limiting base plates at the key parts of the anchor rods to form a net by using high-strength steel strands.

And 7, grouting after the anchor rod. When the anchor rod needs to be further protected, the grouting pipe can be inserted into the reserved small holes in the backing plate and the grout stop plug, cement grout grouting is conducted on the free end of the hollow rod body, and the effects of strengthening anchoring force and preventing corrosion of the anchor rod are achieved.

The invention is described above by way of example with reference to the accompanying drawings, in which it is apparent that the invention may be embodied in practice. The invention is not limited by the above-mentioned modes, and various insubstantial modifications made by the technical scheme of the invention or directly applied to other occasions without modification are within the protection scope of the invention.

Claims (10)

1. The utility model provides a high pressure grout end anchor formula is from boring prestressed anchorage pole which characterized in that: including drill bit (1), anchor material (2), the cavity body of rod (3), slip casting controller (4) and slip casting blender (11), the tip at the cavity body of rod (3) anchor section is connected in drill bit (1), install on the cavity body of rod (3) slip casting controller (4), the both ends of slip casting controller (4) are connected with the cavity body of rod (3) respectively, the tip intercommunication of slip casting blender (11) and the cavity body of rod (3) free end, the inside slip casting passageway that is equipped with of the cavity body of rod (3), anchor material (2) stir in slip casting blender (11) evenly, the slip casting passageway injection of anchor material (2) through the cavity body of rod (3).

2. The high-pressure grouting end-anchored self-drilling prestressed anchor rod of claim 1, wherein: the anchoring material (2) is an A and B two-component material which is mixed according to a certain proportion, after the anchoring material (2) overflows from the drill bit (1), high-pressure grouting is carried out in a closed space of the anchoring section and the anchoring material permeates into cracks of the hole wall, the anchoring material (2) can be solidified within 30-120 seconds, and the end part of the anchor rod is rapidly anchored.

3. The high-pressure grouting end-anchored self-drilling prestressed anchor rod as claimed in claim 1 or 2, wherein: the hollow rod body (3) is made of high-elongation steel, standard wave-shaped threads which are left-handed or right-handed are arranged on the outer surface of the hollow rod body (3), and the hollow rod body (3) is of a hollow structure and serves as a grouting channel.

4. The high-pressure grouting end-anchored self-drilling prestressed anchor rod of claim 3, wherein: the grouting controller (4) comprises a hollow core pipe (41) and a shell (42), wherein two ends of the hollow core pipe (41) are respectively connected with the hollow rod body (3) through standard waveform internal threads, the shell (42) is wrapped outside the hollow core pipe (41), and two end parts of the shell (42) and the hollow core pipe (41) are hermetically connected through a metal fastening ring (43).

5. The high-pressure grouting end-anchored self-drilling prestressed anchor rod as claimed in claim 4, wherein: an enclosed space (44) is formed between the outer wall of the hollow core pipe (41) and the inner wall of the shell (42), a water absorbing material is preset in the enclosed space (44), and the middle of the hollow core pipe (41) is provided with symmetrically distributed one-way valve pulp outlet holes (45).

6. The high-pressure grouting end-anchored self-drilling prestressed anchor rod as claimed in claim 5, wherein: the grouting controller (4) connects the two sections of hollow rod bodies (3) to form a grouting channel, grout flows into the shell (42) from the grout outlet hole (45) of the one-way valve on the hollow core pipe (41) during grouting, the shell (42) expands to completely block the drilled hole, a closed space is formed in the anchoring section, and the anchor rod is centered in the drilled hole after the grouting controller expands.

7. The high-pressure grouting end-anchored self-drilling prestressed anchor rod as claimed in claim 5, wherein: the anchor rod further comprises a limiting base plate (8), the limiting base plate (8) is a conical base plate, a circle of stopping teeth (81) are arranged at a central circular hole of the limiting base plate (8), the stopping teeth (81) are tightly meshed with the wave-shaped threads on the outer surface of the hollow rod body (3), and the limiting base plate (8) can only move forward and cannot move backward on the hollow rod body (3).

8. The high-pressure grouting end-anchored self-drilling prestressed anchor rod of claim 7, wherein: one corner of the limiting base plate (8) is tilted and provided with a through hole (82), and the high-strength steel strand (10) sequentially penetrates through the through holes (82) of the limiting base plates (8) to connect the anchor rods to form integral stress.

9. The high-pressure grouting end-anchored self-drilling prestressed anchor rod as claimed in claim 7, wherein: the anchor rod further comprises a grout stop plug (7), the grout stop plug (7) is arranged at the free end of the hollow rod body (3), and the grout stop plug (7) is located in front of the limiting cushion plate (8).

10. A construction method of a high-pressure grouting end anchor type self-drilling prestressed anchor rod is characterized by comprising the following steps: the high-pressure groutable end-anchored self-drilling prestressed anchor rod as claimed in any one of claims 1 to 9, wherein said construction method comprises the following steps:

step 1, construction preparation: preparing a jumbolter, a grouting system, a rod body and accessories, anchoring materials and high-pressure air/water working conditions required by anchor rod construction;

step 2, drilling and cleaning: connecting the assembled anchor rod with an anchor rod drilling machine, starting the drilling machine to drive the rod body to rotate, cutting the surrounding rock drilled hole by using a drill bit, connecting a high-pressure air/water pipe when the surrounding rock drilled hole is rotated to the designed depth, and cleaning the drilled hole by using the high-pressure air/water pipe;

step 3, firstly, applying axial force to the anchor rod to enable the anchor rod drill bit to be abutted against the surrounding rock at the bottom of the hole; secondly, according to the different types of the grouting controllers, the shell of the grouting controller is expanded to plug the drilled hole in different modes;

and 4, end anchor high-pressure grouting: two feeding pipes of the high-pressure grouting pump are respectively arranged in two storage tanks for storing components A and B of the anchoring materials, and the grouting pipes are connected with the hollow rod body for high-pressure grouting;

step 5, prestress application: installing a limit base plate on the hollow rod body, tensioning the hollow rod body by using an anchor rod installation tool, continuously pushing the limit base plate forward to enable the limit base plate to tightly press the surface of the surrounding rock, loosening the hollow rod body when the tensioning force meets the requirement, and installing a nut behind the limit base plate;

step 6, after all anchor rods are installed, connecting limiting base plates at key positions of the anchor rods to form a net by using high-strength steel strands;

and 7, grouting after the anchor rod: when the anchor rod needs to be further protected, a grouting pipe can be inserted through the limiting base plate and the reserved small hole on the grout stopping plug, and cement grout grouting is conducted on the free end of the hollow rod body.

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