Composite anchor rod and construction method for grouting reinforcement of tunnel face

Abstract

The present invention discloses a composite anchor rod and construction method for face grouting reinforcement, comprising a rod body, the rod body is hollow and grouting holes are evenly arranged on the side wall, a first opening at one end of the rod body is threadedly connected to a drill bit, a second opening at the other end is detachably connected to a solid plug, a sleeve is sleeved on the outside of the rod body, one end of the sleeve is detachably connected to the drill bit, and the rod body and the solid plug are both made of basalt fiber material. The present invention combines a rod body made of basalt fiber material with a detachable sleeve, making full use of the environmentally friendly and easy-to-disassemble characteristics of basalt fiber, compensating for the problem of insufficient torsional strength of the rod body through the sleeve, removing the sleeve, and no need to clean the holes, thereby improving construction efficiency, and grouting the holes through the rod body, thereby improving the physical properties of the rock and soil body and optimizing the reinforcement effect.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering, and particularly relates to a composite anchor rod for grouting reinforcement of a tunnel face and a construction method. Background Art

[0002] At present, the anchors used for face reinforcement are roughly divided into two categories: steel anchors and fiber reinforced composite anchors. Both are solid anchors and cannot improve the physical properties of the face rock mass. In addition, steel anchors have high shear strength and are not easy to break during face excavation. Since self-drilling anchors need to rotate and advance in the rock mass, they require high strength for the rod material, making them difficult to break. In the traditional anchor construction process, it is necessary to drill holes first, clean the holes, set anchors, and inject grout. The construction process is cumbersome and the construction efficiency is low. Summary of the invention

[0003] The object of the present invention is to provide a composite anchor rod and a construction method for grouting reinforcement of a tunnel face, aiming to solve the problems existing in the prior art in the above-mentioned background technology.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A composite anchor rod for face grouting reinforcement comprises a rod body, wherein the rod body is hollow and grouting holes are evenly arranged on the side wall, a first opening at one end of the rod body is threadedly connected to a drill bit, and a second opening at the other end is detachably connected to a solid plug, a casing is sleeved on the outside of the rod body, and one end of the casing is detachably connected to the drill bit, and the rod body and the solid plug are both made of basalt fiber material.

[0006] The drilling rig drives the drill bit to drill holes through the casing. When the drilling is completed, the rod body is synchronously arranged in the borehole, and there is no need to clean the hole again. The rod body and solid plug are made of basalt fiber material, which has low shear strength, is environmentally friendly and easy to dismantle. The casing solves the problem of insufficient torsional strength of the rod body and ensures smooth drilling. When the casing is removed for grouting, the slurry is introduced into the borehole from the rod body along the grouting hole. The slurry combines with the rock and soil to improve the physical properties of the rock and soil and optimize the reinforcement effect.

[0007] Furthermore, a protrusion is provided on the inner wall of the second opening, and the solid plug is provided with a groove adapted to the protrusion. A second threaded rod is provided on the top surface of the solid plug, and the second threaded rod is threadedly connected to a fastening nut. A pad is provided between the fastening nut and the second opening, and the pad is adapted to the size of the top surface of the drill bit. The solid plug is fixed to the second opening through the pad and the fastening nut.

[0008] The combination of the protrusion and the groove facilitates the introduction of the solid plug into the rod body. The solid plug is rotated to misalign the groove and the protrusion, thereby blocking the second opening. Since the pad is adapted to the size of the drill bit, the solid plug is fixed at the second opening by tightening the nut and the pad. At the same time, the pad is used to block the gap between the rod body and the drill hole, thereby avoiding the backflow of slurry after grouting.

[0009] Furthermore, a first threaded rod is provided on the top surface of the drill bit, and an inner wall of the first opening is provided with an internal thread matched with the first threaded rod.

[0010] Furthermore, nail-shaped protrusions are arranged at intervals on the top surface of the drill bit around the first threaded rod, and the protrusions include a nail cap and a nail rod, and the two ends of the nail rod are respectively vertically connected to the nail cap and the drill bit, and the radial dimension of the nail cap is larger than the radial dimension of the nail rod, and the end surface of the sleeve is provided with a connecting hole corresponding to the protrusion, the central dimension of the connecting hole is adapted to the top cap, and the two sides of the center of the connecting hole are respectively adapted to the size of the nail rod, and the connecting hole and the protrusion are detachably connected.

[0011] The drill bit is detachably connected to the connecting hole on the end face of the casing through a nail-shaped protrusion. When the casing is installed, the nail cap is aligned with the center of the connecting hole and inserted, and the casing is rotated to rotate the nail rod to one side of the connecting hole. The nail cap is clamped in the connecting hole, thereby fixing the casing and the drill bit. After the drilling is completed, the casing is rotated to align the center of the connecting hole with the nail cap and the casing can be removed. The installation and disassembly are relatively convenient and the casing can be reused.

[0012] Furthermore, the sleeve is made of stainless steel, which can provide good torsional strength and has a certain corrosion resistance.

[0013] Furthermore, the outer diameter of the casing is smaller than the diameter of the top surface of the drill bit, so that the drill hole is slightly larger than the casing, which facilitates the removal of the casing.

[0014] A construction method using a composite anchor rod for grouting reinforcement of a tunnel face comprises the following steps:

[0015] 1) Design two sets of face anchor layout methods that meet the requirements of face stability and the layout positions cannot be repeated;

[0016] 2) Mark the drilling positions according to the first set of layout methods;

[0017] 3) Drill and grout at the marked locations using composite anchors;

[0018] 4) Carry out system support and wait for the slurry to solidify, wherein the system support includes initial support and secondary lining;

[0019] 5) Carry out full-section excavation of the tunnel face;

[0020] 6) Stop excavation when the remaining length of the anchor rod is 1 / 3 of its original length, and mark the drilling position according to the second set of layout methods;

[0021] 7) Carry out construction from step 3) to step 5) according to the second set of layout positions;

[0022] 8) Stop excavation when the remaining length of the anchor rod is 1 / 3 of its original length, and mark the drilling position according to the first set of layout methods;

[0023] 9) Carry out the above-mentioned cyclic construction according to the first and second sets of layout in sequence to complete the overall excavation of the tunnel.

[0024] The step-by-step construction method is used to maintain the stability of the face during tunnel excavation, thus avoiding the problem of unstable face support caused by the gradual weakening of the face anchor support strength as the face is excavated under the traditional layout method.

[0025] Furthermore, the steps of drilling and grouting at the marked position using the composite anchor rod in step 3) are as follows:

[0026] 1) Connect the drill bit to the rod body, connect one end of the casing to the drill bit, rotate the casing along the drilling direction of the drill rig, rotate the nail rod to one side of the center of the connecting hole, and connect the other end of the casing to the drill rig;

[0027] 2) Use the assembled composite anchor rod to drill holes according to the marked positions;

[0028] 3) After drilling is completed, rotate and adjust the position of the sleeve so that the nail cap corresponds to the center of the connecting hole, and remove the sleeve;

[0029] 4) Grouting is injected into the rod body through the second opening, and the grouting liquid enters the borehole along the grouting hole to improve the physical properties of the rock and soil;

[0030] 5) Align the groove of the solid plug with the protrusion of the rod body, insert the solid plug into the rod body along the second opening, rotate the solid plug to misalign the groove and the protrusion, and abut the top surface of the solid plug against the protrusion. Insert the pad into the second threaded rod, screw the fastening nut into the second threaded rod, and fix the solid plug to the second opening of the rod body through the pad and the fastening nut to seal the slurry and complete the grouting.

[0031] Compared with the shortcomings and deficiencies of the prior art, the present invention has the following beneficial effects:

[0032] 1. The anchor rod in the present invention adopts a hollow rod body and is provided with a grouting hole. The rod body is made of basalt fiber material, which is easy to dismantle and environmentally friendly. The casing is made of stainless steel material, which can effectively make up for the insufficient torsional strength of the rod body. After the drilling is completed, the casing is removed, and there is no need to clean the hole and place the anchor rod, which improves the construction efficiency. Grouting is done into the rod body, and the slurry is injected into the drill hole along the grouting hole to improve the physical properties of the rock and soil.

[0033] 2. The casing and the drill bit are detachably connected through the nail-shaped protrusion and the connecting hole. The casing can be loaded and unloaded by rotating the casing to adjust the position of the nail cap and the center of the connecting hole. The connection between the casing and the drill bit is stable, the casing is easy and quick to load and unload, and the casing can be reused, saving enterprise costs.

[0034] 3. Compared with the traditional intermittent construction method, the step-by-step construction method can effectively solve the problem of gradual weakening of support strength during tunnel excavation, resulting in excessive deformation of the face, and improve construction efficiency by using composite anchor drilling and grouting. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The figure is a schematic diagram of the cross-sectional structure of a composite anchor rod used for grouting reinforcement of a tunnel face in an embodiment of the present invention.

[0036] Figure 2 Schematic diagram of the structure of the rod body in the embodiment of the present invention.

[0037] Figure 3 Schematic diagram of the structure of the second opening end surface of the rod body in an embodiment of the present invention.

[0038] Figure 4 Schematic diagram of the structure of the solid plug in the embodiment of the present invention.

[0039] Figure 5 Schematic diagram of the top view of the solid plug in the embodiment of the present invention.

[0040] Figure 6 Schematic diagram of the structure of the drill bit in the embodiment of the present invention.

[0041] Figure 7 1 is a schematic diagram of the top view of the drill bit in an embodiment of the present invention.

[0042] Figure 8 It is a schematic structural diagram of the connecting end surface of the casing and the drill bit in an embodiment of the present invention.

[0043] Fig. 9 This is a schematic diagram of the first layout structure in the tunnel according to an embodiment of the present invention.

[0044] Fig.10 It is a schematic diagram of the second layout structure in the tunnel in an embodiment of the present invention.

[0045] In the figure: 1-rod body; 11-grouting hole; 12-first opening; 13-second opening; 131-bump; 2-drill bit; 21-first threaded rod; 22-protrusion; 221-nail cap; 222-nail rod; 3-solid plug; 31-second threaded rod; 32-groove; 4-pad; 5-fastening nut; 6-casing; 61-connecting hole; 7-tunnel; 8-first set of layout; 9-second set of layout. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0047] Reference Figure 1 A composite anchor for face grouting reinforcement includes a rod body 1, which is made of basalt fiber material (BFRP) and has the characteristics of low shear strength, easy to break and environmentally friendly. (Refer to Figure 2 ) The rod body 1 is a hollow cylindrical structure, and its side wall is evenly provided with grouting holes 11. A first opening 12 and a second opening 13 are respectively provided at both ends of the rod body 1, wherein the first opening 12 is detachably connected to the drill bit 2. Specifically, the drill bit 2 is threadedly connected to the first opening 12 of the rod body 1, and the inner wall of the first opening 12 is provided with an internal thread. A first threaded rod 21 is provided on the top surface of the drill bit 2. The drill bit 2 is threadedly connected to the rod body 1 through the first threaded rod 21. The drill bit 2 adopts an alloy steel drill bit to facilitate its entry into the rock and soil. The second opening 13 at the other end of the rod body 1 is detachably connected to the solid plug 3 for sealing the slurry to prevent the slurry from flowing back. The cross-sectional size of the solid plug 3 is adapted to the inner cross-sectional size of the rod body 1, and the solid plug 3 is made of basalt fiber material.

[0048] Reference Figure 3 The inner wall of the second opening 13 is provided with a protrusion 131, and the extension direction of the protrusion 131 is the same as the length direction of the rod body 1. Preferably, a plurality of protrusions 131 are evenly spaced on the side wall of the second opening 13 (refer to Figure 4 and Figure 5 ) The side wall of the solid plug 3 is provided with a groove 32 adapted to the protrusion 131, and the number of the grooves 32 corresponds to the protrusion 131. The outer top surface of the solid plug 3 is provided with a second threaded rod 31. The solid plug 3 penetrates into the rod body 1 along the second opening 13. The solid plug 3 is rotated so that the positions of the groove 32 and the protrusion 131 are staggered, so that the outer top surface of the solid plug 3 abuts against the protrusion 131. The part of the second threaded rod 31 extending out of the second opening 13 is sleeved with a pad 4. The size of the pad 4 is adapted to the size of the top surface of the drill bit 2. The second threaded rod 31 is fixed to the pad 4 by a fastening nut 5 threadedly connected thereto. The solid plug 3 seals the second opening 13 of the rod body 1. The pad 4 can not only fix the solid plug 3, but also block the gap between the rod body 1 and the drill hole to prevent slurry from flowing out.

[0049] Reference Figure 6-Figure 8 The top surface of the drill bit 2 can be detachably connected to the sleeve 6. The sleeve 6 is made of stainless steel material, has a certain structural strength, and has a low manufacturing cost and is easy to obtain. The outer ring side wall size of the sleeve 6 is smaller than the top surface size of the drill bit 2. The sleeve 6 is sleeved on the outside of the rod body 1. A gap is left between the inner wall of the sleeve 6 and the rod body 1 to facilitate the loading and unloading of the sleeve 6. Specifically, a protrusion 22 is provided on the top surface of the drill bit 2. The protrusion 22 is a nail-shaped structure, including a nail cap 221 and a nail rod 222. The two ends of the nail rod 222 are respectively vertically connected to the top surface of the drill bit 2 and the nail cap 221. The connecting surface of the sleeve 6 and the drill bit 2 is provided with a connecting hole 61, the center of the connection hole 61 is adapted to the shape and size of the nail cap 221, and the two sides of the center are adapted to the size of the nail rod 222, wherein the nail cap 221 extends into the center of the connection hole 61, the sleeve 6 is connected to the drill bit 2, the drill drives the drill bit 2 to rotate through the sleeve 6, and the corresponding nail rod 222 rotates to one side of the center of the connection hole 61. When the drill bit 2 needs to be withdrawn, the drill rotates in the opposite direction, and the corresponding nail rod 222 rotates to the other side of the center of the connection hole 61 and drives the drill bit 2 to rotate in the opposite direction to withdraw. After the drilling is completed, the center of the connection hole 61 is aligned with the nail cap 221, and the sleeve 6 can be removed. The sleeve 6 is used to increase the torsional strength of the rod body 1 when drilling, and has a certain anti-corrosion effect.

[0050] A plurality of connection holes 61 are evenly arranged along the end surface of the sleeve 6 , and the positions and number of the protrusions 22 match the connection holes 61 . Preferably, four connection holes 61 and four protrusions 22 are arranged respectively.

[0051] A construction method using the composite anchor drilling and grouting method comprises the following steps:

[0052] 1. The drill bit 2 is connected to the rod body 1 by threading the first threaded rod 21 on the top surface of the drill bit 2 with the first opening 11 of the rod body 1. The center of the connecting hole 61 on one end surface of the sleeve 6 is aligned with the nail cap 221 on the top surface of the drill bit 2 and inserted. The sleeve 6 is rotated along the drilling direction of the drill rig to rotate the nail rod 222 to one side of the center of the connecting hole 61. The other end of the sleeve 6 is connected to the drill rig;

[0053] 2. Use the assembled composite anchor rod to drill holes at the marked positions;

[0054] 3. After the drilling is completed, the position of the sleeve 6 is adjusted by rotation so that the nail cap 221 corresponds to the central position of the connecting hole 61, and the sleeve 6 is removed without cleaning the hole and placing the anchor rod;

[0055] 4. Grouting is injected into the rod body 1 through the second opening 13 at the top of the rod body 1. After the grouting enters the rod body 1, it evenly enters the drill hole along the grouting hole 11 to improve the physical properties of the rock and soil and optimize the reinforcement effect;

[0056] 5. In order to prevent the slurry from flowing back, align the groove 32 of the solid plug 3 with the protrusion 131 of the rod body 1, and insert the solid plug 3 along the second opening 13 of the rod body 1, rotate the solid plug 3 to make the groove 32 and the protrusion 131 misaligned, and the top surface of the solid plug 3 abuts against the end surface of the protrusion 131, insert the pad 4 into the second threaded rod 31, and screw the fastening nut 5 into the second threaded rod 31, so that the solid plug 3 is fixed to the second opening 13 of the rod body 1 through the pad 4 and the fastening nut 5, the solid plug 3 is used to block the second opening 13 of the rod body 1, and the pad 4 is used to block the gap between the rod body 1 and the wall of the drilled hole to prevent the slurry from flowing out, thereby completing the grouting.

[0057] Reference Fig. 9 and Fig.10 A step-by-step construction method using the composite anchor drilling and grouting method comprises the following steps:

[0058] S1. When determining the layout position of the face anchor bolts, design at least two sets of layout methods. The layout methods must meet the requirements of face stability, and the layout positions cannot be repeated. The following takes two sets of layout methods as an example;

[0059] S2, mark the drilling positions according to the first set of layout 8 methods;

[0060] S3, according to the above-mentioned composite anchor drilling and grouting construction method, drilling and grouting at the drilling positions marked in the first set of layout 8;

[0061] S4, while waiting for the slurry to solidify, the system support includes initial support and secondary lining;

[0062] S5. After the system support is completed, the full section of the tunnel face is excavated;

[0063] S6. Stop excavating when the remaining length of the anchor rod is X of its original length. Preferably, the remaining length of the anchor rod is 1 / 3 of the original length, that is, X=1 / 3;

[0064] S7, mark the drilling positions according to the second set of layout methods, and carry out the construction of S3 to S5 according to the second set of layout 9 positions;

[0065] S8. Stop excavating when the remaining length of the anchor rod is 1 / 3 of its original length, and mark the drilling position again according to the first set of layout 8 methods;

[0066] S9, carry out the above-mentioned cyclic construction according to the first and second sets of layouts in sequence to complete the overall excavation of tunnel 7.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A composite anchor for face grouting reinforcement, characterized in that: The invention comprises a rod body, which is hollow and has grouting holes evenly arranged on the side walls. A first opening at one end of the rod body is threadedly connected to a drill bit, and a second opening at the other end is detachably connected to a solid plug. A casing is sleeved on the outside of the rod body, and one end of the casing is detachably connected to the drill bit. The rod body and the solid plug are both made of basalt fiber material. A first threaded rod is provided on the top surface of the drill bit, an internal thread matching the first threaded rod is provided on the inner wall of the first opening, and nail-shaped protrusions are arranged at intervals around the first threaded rod on the top surface of the drill bit. The protrusion comprises a nail cap and a nail rod, and the nail cap and the drill bit are respectively vertically connected at both ends of the nail rod, the radial size of the nail cap is larger than the radial size of the nail rod, and a connecting hole corresponding to the protrusion is provided on the end surface of the casing, the central size of the connecting hole is matched with the nail cap, and the two sides of the center of the connecting hole are respectively matched with the size of the nail rod, and the connecting hole and the protrusion are detachably connected.

2. The composite anchor for grouting reinforcement of the tunnel face according to claim 1, characterized in that: A protrusion is provided on the inner wall of the second opening, and the solid plug is provided with a groove adapted to the protrusion. A second threaded rod is provided on the top surface of the solid plug, and the second threaded rod is threadedly connected to a fastening nut. A pad is provided between the fastening nut and the second opening, and the pad is adapted to the size of the top surface of the drill bit. The solid plug is fixed to the second opening through the pad and the fastening nut.

3. The composite anchor for grouting reinforcement of the tunnel face according to claim 2, characterized in that: The sleeve is made of stainless steel.

4. The composite anchor for grouting reinforcement of the tunnel face according to claim 3, characterized in that: The outer diameter of the casing is smaller than the diameter of the top surface of the drill bit.

5. A construction method for composite anchor bolts for grouting reinforcement of a tunnel face according to any one of claims 1 to 4, characterized in that The steps include: 1) Design two sets of face anchor layout methods that meet the requirements of face stability and the layout positions cannot be repeated; 2) Mark the drilling positions according to the first set of layout methods; 3) Drill and grout at the marked locations using composite anchors; 4) Carry out system support and wait for the slurry to solidify, wherein the system support includes initial support and secondary lining; 5) Carry out full-section excavation of the tunnel face; 6) Stop excavation when the remaining length of the anchor rod is 1 / 3 of its original length, and mark the drilling position according to the second set of layout methods; 7) Carry out construction from step 3) to step 5) according to the second layout position; 8) Stop excavation when the remaining length of the anchor rod is 1 / 3 of its original length, and mark the drilling position again according to the first set of layout methods; 9) Carry out construction in a cycle according to the first and second sets of layouts mentioned above to complete the overall excavation of the tunnel.

6. The construction method according to claim 5, characterized in that: The steps of drilling and grouting at the marked position using the composite anchor described in step 3) are as follows: 1) Connect the drill bit to the rod body, connect one end of the casing to the drill bit, rotate the casing along the drilling direction of the drill rig, rotate the nail rod to one side of the center of the connecting hole, and connect the other end of the casing to the drill rig; 2) Use the assembled composite anchor rod to drill holes according to the marked positions; 3) After drilling is completed, rotate and adjust the position of the sleeve so that the nail cap corresponds to the center of the connecting hole, and remove the sleeve; 4) Grouting is injected into the rod body through the second opening, and the grouting liquid enters the borehole along the grouting hole to improve the physical properties of the rock and soil; 5) Align the groove of the solid plug with the protrusion of the rod body, insert the solid plug into the rod body along the second opening, rotate the solid plug to misalign the groove and the protrusion, and abut the top surface of the solid plug against the protrusion. Insert the pad into the second threaded rod, screw the fastening nut into the second threaded rod, and fix the solid plug to the second opening of the rod body through the pad and the fastening nut to seal the slurry and complete the grouting.

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