Built-in resin prestressed hollow anchor rod

Abstract

This invention discloses a hollow prestressed anchor rod with built-in resin, comprising a first anchor rod and a second anchor rod with a hollow axis. One end of the second anchor rod is sealed through the insertion end of the first anchor rod, and the other end has an internal sealing plate to form a sealed cavity filled with a quick-setting resin. An anchor head is installed at the anchoring end of the second anchor rod, and the anchor head is equipped with a striking pin for pressing and piercing the sealing plate to release the built-in resin. A positioning component is provided at the free end of the first anchor rod, and a cement slurry spray hole is opened in the middle of the first anchor rod. This invention avoids the drawbacks of traditional bagged resin filling and fixing methods by replacing the traditional method with a built-in anchor rod filling structure, which is a two-section anchor rod structure. The resin is sealed by the sealing structure to prevent premature curing, and then the resin is squeezed out by the tail end of the anchor rod, making the resin filling more uniform. Moreover, under the extrusion state, the resin can enter the rock strata fissures, expanding the fixing layer and making the fixing more stable.

Description

Technical Field

[0001] This invention belongs to the technical field of anchoring equipment, and in particular relates to a hollow anchor rod with built-in resin prestress. Background Technology

[0002] Rock bolts are a fundamental component of roadway support in modern coal mines. They reinforce the surrounding rock, allowing it to support itself. Rock bolts are used not only in mines but also in engineering projects for the main reinforcement of slopes, tunnels, and dams. As a tension member extending deep into the ground, one end of the rock bolt connects to the engineering structure, while the other end penetrates into the ground. The entire rock bolt consists of a free section and an anchored section. The free section is the area that transmits the tension at the bolt head to the anchored body; its function is to apply prestress to the bolt. By applying prestress to the free end of the bolt, it provides support in the opposite direction to slope collapse, thus not only reinforcing the slope but also reducing the possibility of further collapse.

[0003] Existing anchor bolts have multiple functions, among which the prestressing anchor bolts are mainly expansion-shell anchor bolts. These bolts extend into a pre-drilled hole, and rotating the bolt causes the anchor head to expand, creating support against the borehole sidewall and fixing the anchoring end. A certain amount of prestress can be applied to the free end of the bolt, followed by grouting. After the cement grout solidifies, the prestressed anchoring process is complete. However, expansion-shell anchor bolts offer only one type of fixation, and applying prestress after the anchor head is fixed can cause the anchor bolt to shift off-center from the borehole axis, resulting in insufficient stability after subsequent grouting.

[0004] Existing resin prestressed anchor bolts use resin contained in strip-shaped plastic bags, which are inserted into the borehole after drilling, followed by the insertion of the anchor bolt. The anchor head consists of a spiral-shaped head. During the spiraling process, the resin bag breaks, distributing the liquid resin evenly around the circumference of the anchor bolt. The resin then rapidly solidifies, fixing the anchoring end of the bolt and forming a reinforced section. Prestress is then applied to the tail end of the anchor bolt. Compared to expansion-shell anchor bolts, this method provides a longer reinforced section and more stable fixation. However, the resin bag lacks a rigid structure, making it difficult to insert and prone to deformation. Furthermore, the bag is fragile and easily breaks due to friction against the borehole wall, causing the borehole to be prematurely sealed by the resin. Summary of the Invention

[0005] The purpose of this invention is to provide a hollow anchor bolt with built-in resin prestressing, which solves the problems of difficult filling, cumbersome installation, and easy premature breakage of the bag in existing bagged resin prestressed anchor bolts.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: A hollow anchor rod with built-in resin prestressing includes a first anchor rod and a second anchor rod that are hollow along the axis. Both anchor rods have threaded grooves on their surfaces. The first anchor rod and the second anchor rod are coaxially arranged and their ends are sleeved together. One end of the second anchor rod is sealed through the insertion end of the first anchor rod, and the other end has a built-in sealing plate to form a sealed cavity for filling with a quick-setting resin agent; The second anchor rod is equipped with an anchor head at the corresponding anchoring end. The anchor head is equipped with a striker, which is used to pierce the sealing plate after pressing and release the built-in resin agent. The end of the first anchor rod is sleeved on the inner cavity of the second anchor rod and expands and contracts to squeeze the cavity of the second anchor rod, so that the resin agent is sprayed out from the free end of the second anchor rod. The first anchor rod has a positioning component at its free end and a cement slurry injection hole in the middle.

[0007] Furthermore, the free end of the second anchor rod has a cylindrical hole that communicates with the internal cavity. The cylindrical hole is coaxial with the second anchor rod. The cylindrical hole is used to install a striker. One end of the striker is fixed to the anchor head, and the other end is a pointed tip that faces the sealing plate.

[0008] The anchor head is a conical structure with a striking pin fixed at the center of the circular surface. Barbs are evenly arranged around the circumference of the striking pin. One end of each barb is hinged to the anchor head, and the other end is a pointed tip. The free end of the second anchor rod is provided with a groove to accommodate the barbs. The groove has a smooth inclined surface, which is used to drive the barbs to complete the extended hinged flip when the second anchor rod is pressed.

[0009] Furthermore, the circumferential side of the barb in its retracted state is secured with an adhesive ring. A resin spray hole is provided on the inclined surface corresponding to the groove.

[0010] Furthermore, the second anchor cavity is provided with a limiting ring for installing a sealing plate, which is used to fix the sealing plate, and the surface of the sealing plate is provided with a groove that is easily damaged.

[0011] The positioning assembly includes a grout stopper, a washer, and a nut.

[0012] The second anchor rod has a threaded sleeve fixed to its end. The threaded sleeve has an internal thread that fits the external thread of the first anchor rod. A piston is provided at the mating end of the first anchor rod to improve sealing during expansion and contraction.

[0013] The present invention has the following advantages: The present invention avoids the drawbacks of the traditional bag-type resin filling and fixing method, and instead adopts an anchor rod built-in filling structure, and is a two-section anchor rod structure. The resin is sealed by the sealing structure to prevent premature curing. Then, the resin is squeezed out by the tail end anchor rod, which makes the filling of the resin more uniform. Moreover, under the extrusion state, the resin can enter the rock strata gaps, expand the fixing layer, and make the fixing more stable.

[0014] Not only is the anchor rod a two-section structure, but there are also two types of curing agents used for curing. The resin agent at the front end is used to fix the second anchor rod, which facilitates quick fixing and the application of prestress. The cement slurry curing agent on the circumference of the first anchor rod at the rear end has the characteristics of corrosion resistance, durability, and low cost, and has stronger overall performance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0016] Figure 1 : A magnified schematic diagram of the anchor head storage state and positioning component of the present invention.

[0017] Figure 2 : An enlarged structural diagram of the second anchor bolt in the cut state, the unfolded state of the anchor head, and the tail end connection of the present invention.

[0018] Figure 3 : Schematic diagram of the anchor head installation and mating structure in the cross-sectional state of the second anchor rod of the present invention.

[0019] Figure 4 : Schematic diagram of the structure of the anchor bolt insertion hole and the flow direction of the curing agent in this invention.

[0020] Figure 5 : Schematic diagram of the installation and mating structure of the second anchor rod and anchor head of the present invention.

[0021] The components represented by each number in the attached diagram are listed below: First anchor rod 1, Second anchor rod 2, Sealing plate 4, Anchor head 3, Impact pin 31, Cement grout injection hole 11, Cylindrical hole 21, Barb 32, Groove 23, Rubber ring 33, Resin agent injection hole 22, Limiting ring 24, Cable groove 41, Grout stop plug 51, Gasket 52, Nut 53, Screw sleeve 25, Piston 12. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] like Figures 1-2 As shown: A hollow anchor rod with built-in resin prestressing includes a first anchor rod 1 and a second anchor rod 2 with a hollow axis. Both anchor rods have threaded grooves on their surfaces. The first anchor rod 1 and the second anchor rod 2 are coaxially arranged and their ends are sleeved together. The first anchor rod 1 and the second anchor rod 2 both have threaded grooves on their surfaces, similar to a threaded steel structure.

[0024] One end of the second anchor rod 2 is sealed through the insertion end of the first anchor rod 1, and the other end has a built-in sealing plate 4 to form a sealed cavity for filling with a quick-setting resin agent. The cavity is a cylindrical cavity, and the quick-setting resin agent is in a liquid gel state. After contact with air, it will quickly set and solidify in a short time of about 5-10 minutes.

[0025] An anchor head 3 is installed at the anchoring end of the second anchor rod 2. The anchor head 3 is equipped with a striking pin 31, which is used to pierce the sealing plate 4 after pressing and release the built-in resin agent. The end of the first anchor rod 1 is sleeved in the inner cavity of the second anchor rod 2 and expands and contracts to squeeze the cavity of the second anchor rod 2, so that the resin agent is sprayed out from the free end of the second anchor rod 2. The first anchor rod 1 has a positioning component at its free end, and a cement slurry ejection hole 11 is opened in the middle of the first anchor rod 1.

[0026] The cavity of the second anchor rod 2 serves as a sealed space, preventing the resin from contacting air and ensuring proper storage. During use, a borehole is drilled and cleaned to create a diameter larger than the anchor rod's diameter. The anchor rod is then inserted, with its anchoring end corresponding to the anchor head. The anchor head stops when it contacts the bottom of the borehole, and the free end of the first anchor rod 1 is pressed down. The anchor head 3, equipped with a striking pin 31 facing the sealing plate, pierces the sealing plate 4. Further pressing of the first anchor rod 1 compresses the cavity of the second anchor rod 2, forcing the resin out from its free end. The resin overflows and fills the spiral groove around the outer side of the second anchor rod 2, not only covering the circumference of the borehole corresponding to the second anchor rod 2, but also, through compression, penetrating the fissures in the rock strata around the borehole.

[0027] Wait a moment for the resin to cure, then apply prestress to the free end of the first anchor rod 1. Generally, apply stress first in the direction of rock collapse. After completion, fix the free end of the first anchor rod 1 through the positioning component. Inject cement grout through the hollow channel of the first anchor rod 1 and observe whether the pressure gauge of the grouting machine reaches the pressure value, or observe whether there is mud overflowing from the borehole opening.

[0028] This invention avoids the drawbacks of traditional bagged resin filling and fixing methods, and instead uses an anchor rod built-in filling structure, which is a two-section anchor rod structure. The resin is sealed by a sealing structure to prevent premature curing, and then the resin is squeezed out by the tail end of the anchor rod, making the resin filling more uniform. Moreover, under the extrusion state, the resin can enter the rock strata crevices, expanding the fixing layer and making the fixing more stable.

[0029] Not only is the anchor rod a two-section structure, but there are also two types of curing agents used for curing. The resin agent at the front end is used to fix the second anchor rod, which facilitates quick fixing and the application of prestress. The cement slurry curing agent on the circumference of the first anchor rod at the rear end has the characteristics of corrosion resistance, durability, and low cost, and has stronger overall performance.

[0030] like Figure 3 As shown: The free end of the second anchor rod 2 has a cylindrical hole 21 that connects to the internal cavity. The cylindrical hole 21 is coaxially arranged with the second anchor rod 2. The cylindrical hole 21 is used to fit and install the striking pin 31. One end of the striking pin 31 is fixed to the anchor head 3, and the other end is a pointed tip facing the sealing plate. The striking pin 31 is a columnar rod structure that fits into the cylindrical hole 21 with a clearance fit, allowing for stable extension and contraction in the length direction. Pressing the anchor head 3 causes the tip of the striking pin 31 to pierce the sealing plate 4. The sealing plate 4 is a thin and brittle structure that breaks upon contact with the striking pin 31.

[0031] like Figures 3-5 As shown: The anchor head 3 has a conical structure. The striking pin 31 is fixed at the center of the circular surface. Barbs 32 are evenly arranged around the circumference of the striking pin 31. One end of each barb 32 is hinged to the anchor head 3, and the other end is a pointed tip. The free end of the second anchor rod 2 is provided with a groove 23 to accommodate the barbs 32. The groove 23 has a smooth inclined surface. When the second anchor rod 2 is pressed, the barbs 32 are driven by the inclined surface to complete the extended hinged flip. The barbs 32 consist of four groups, with a flat structure. One end is a hinged end with a hinge hole. The anchor head 3 has a corresponding mounting groove to accommodate the hinged end of the barbs, which is used to separate the barbs 32. A hinge shaft is installed in the mounting groove. The other end of the barb is a pointed tip with a smooth inner section for abutting the inclined surface of the groove. The outer side of the barb has a raised ridge to increase friction. The barbs 32 and the groove 23 are in an overlapping state. When the second anchor rod 2 is pressed, the inclined surface and the smooth section of the barb 32 slide out of alignment, and the barb flips to form an expanded state, forming a positioning in the drill hole. This allows the barb 32 to not only pierce the sealing plate 4 through the impact pin 31 after pressing, but also expand and engage with the inner wall of the drill hole, making the anchor head 3 end of the anchor rod more stable. At the same time, the uniformly expanded barb 32 structure can center the anchor rod, making the entire anchor rod coaxial with the drill hole. The gap between the edge of the anchor rod and the drill hole is uniform, and the contact of the filling curing agent is better, allowing for better stress distribution.

[0032] like Figure 1 As shown in the enlarged section: the circumferential side of the barb 32 in its retracted state is secured with a rubber ring 33. The barb 32 and the inclined surface of the groove 23 simultaneously react with the anchor head 3, keeping the anchor head 3 separated from the free end of the second anchor rod 2, preventing accidental contact that could cause the striking pin 31 to pierce the sealing plate 4.

[0033] like Figure 5 As shown in the enlarged section: the inclined surface of the tank 23 is provided with resin spray holes 22. When the barbs 32 are retracted, they can cover the inclined surface and block the resin spray holes. When unfolded, the spray holes can be exposed, allowing the resin to be sprayed evenly along the free end of the second anchor rod 2. The resin fills the gaps evenly along the spiral groove of the second anchor rod 2 from the inside out.

[0034] like Figure 3As shown in the enlarged section: The cavity of the second anchor rod 2 is provided with a limiting ring 24 for installing the sealing plate 4, which is used to fix the sealing plate 4. The surface of the sealing plate 4 is provided with easily broken grooves 41. The grooves 41 are distributed in a star shape. When impacted by the firing pin 31, the sealing plate 4 is easily broken into multiple fragments along the position of the grooves 41.

[0035] like Figure 1 As shown in the enlarged section: the positioning assembly includes a grout stop plug 51, a washer 52, and a nut 53. The washer is square with a central arched section and a through hole for the first anchor rod to pass through. The inner thread of the nut matches the outer thread of the first anchor rod, facilitating screwing in for fixation.

[0036] like Figure 2 As shown in the enlarged section: A threaded sleeve 25 is fixed to the end of the second anchor rod 2. The threaded sleeve 25 has an internal thread that fits the external thread of the first anchor rod 1. The rotation of the first anchor rod 1 achieves the purpose of screwing in and squeezing the resin. The free end of the first anchor rod 1 can be fixed by a connecting sleeve installed on the drilling rig, enabling rapid rotation of the first anchor rod 1 and the effect of screwing in and squeezing. A piston 12 is provided at the mating end of the first anchor rod 1 to improve the sealing during the expansion and contraction process.

[0037] These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can better understand and utilize the present invention.

Claims

1. A hollow anchor bolt with built-in resin prestressing, characterized in that: It includes a first anchor rod (1) and a second anchor rod (2) with a hollow axis, both of which have threaded grooves on their surfaces. The first anchor rod (1) and the second anchor rod (2) are coaxially arranged and their ends are sleeved together. One end of the second anchor rod (2) is sealed through the insertion end of the first anchor rod (1), and the other end has a built-in sealing plate (4) to form a sealed cavity for filling with a quick-setting resin agent; The second anchor rod (2) has an anchor head (3) installed at the corresponding anchoring end. The anchor head (3) is equipped with a striker (31) for pressing and piercing the sealing plate (4) to release the built-in resin agent. The end of the first anchor rod (1) is sleeved in the inner cavity of the second anchor rod (2) and expands and contracts to squeeze the cavity of the second anchor rod (2) so that the resin agent is sprayed out from the free end of the second anchor rod (2). The first anchor rod (1) is provided with a positioning component at its free end, and a cement slurry ejection hole (11) is opened in the middle of the first anchor rod (1).

2. The hollow anchor bolt with built-in resin prestressing according to claim 1, characterized in that: The free end of the second anchor rod (2) has a cylindrical hole (21) that connects to the internal cavity. The cylindrical hole (21) is coaxial with the second anchor rod (2). The cylindrical hole (21) is used to fit and install the striker (31). One end of the striker (31) is fixed to the anchor head (3), and the other end is a pointed tip facing the sealing plate.

3. The hollow anchor bolt with built-in resin prestressing according to claim 2, characterized in that: The anchor head (3) is a conical structure. The striking pin (31) is fixed at the center of the circular surface. Barbs (32) are evenly arranged around the circumference of the striking pin (31). One end of each barb (32) is hinged to the anchor head (3), and the other end is a pointed tip. The free end of the second anchor rod (2) is provided with a groove (23) to accommodate the barbs (32). The groove (23) has a smooth inclined surface. When the second anchor rod (2) is pressed, the barbs (32) are driven by the inclined surface to complete the extended hinged flip.

4. The hollow anchor bolt with built-in resin prestressing according to claim 3, characterized in that: The barbs (32) are wrapped with rubber rings (33) on their circumferential side when they are in the retracted state.

5. The hollow anchor bolt with built-in resin prestressing according to claim 3, characterized in that: The inclined surface of the tank (23) is provided with resin spray holes (22).

6. The hollow anchor bolt with built-in resin prestressing according to claim 2, characterized in that: The second anchor rod (2) cavity is provided with a limiting ring (24) for installing the sealing plate, which is used to fix the sealing plate (4). The surface of the sealing plate (4) is provided with a groove (41) that is easy to break.

7. The hollow anchor bolt with built-in resin prestressing according to claim 1, characterized in that: The positioning assembly includes a grout stopper (51), a washer (52), and a nut (53).

8. The hollow anchor bolt with built-in resin prestressing according to claim 1, characterized in that: The second anchor rod (2) is fixed with a threaded sleeve (25) at its end. The threaded sleeve (25) has an internal thread that is adapted to the external thread of the first anchor rod (1) and is threadedly engaged.

9. The hollow anchor bolt with built-in resin prestressing according to claim 8, characterized in that: The first anchor rod (1) is provided with a piston (12) at the docking end to improve the sealing during the expansion and contraction process.

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