A prestressed anchor rod

Abstract

The application relates to the technical field of building foundation construction, in particular to a prestressed anchor rod, which comprises a hollow anchor rod body, a backing plate, a connecting piece, a swelling shell anchoring piece and an exhaust pipe. The hollow anchor rod body is arranged in a rock stratum hole, the end of the rock stratum hole far from the hole mouth is an output end, and the other end is an input end. The swelling shell anchoring piece is arranged at one end of the hollow anchor rod body close to the output end. The connecting piece is detachably arranged at one end of the hollow anchor rod body close to the input end. The backing plate is arranged on the hollow anchor rod body, the connecting piece is pressed against the front surface of the backing plate, the back surface of the backing plate is pressed against the hole wall of the rock stratum hole, one end of the exhaust pipe is connected into the rock stratum hole, and the other end extends outward. A cement grouting layer is further arranged in the rock stratum hole. The prestressed anchor rod can meet the supporting capacity and improve the installation convenience.

Description

Technical Field

[0001] This application relates to the technical field of building foundation construction, and in particular to a prestressed anchor rod. Background Technology

[0002] In the field of geotechnical engineering, support technology plays a crucial role in ensuring the stability and safety of engineering structures. With the continuous development of various geotechnical engineering projects, such as tunnel excavation, mining, and slope reinforcement, the demand for efficient and reliable support methods is becoming increasingly urgent. Effective support technology can prevent deformation and collapse of the soil and rock mass, ensuring the smooth progress of construction, while also guaranteeing the long-term stability of the project and reducing safety hazards and economic losses caused by soil and rock instability.

[0003] Traditional anchor bolt support is a common support method, which involves inserting anchor bolts into holes in the rock strata and utilizing the friction between the anchor bolt and the rock mass to provide support force. Existing technologies, such as CN111962509B, disclose a prestressed monitoring anchor bolt structure. This scheme places a stress gauge in the middle of the anchor bolt body, along with a centering bracket and a torsional fixing component at the borehole opening. A grout plug is used to divide the anchored section and the free section, enabling segmented grouting and monitoring of prestress loss in the anchor bolt. This scheme allows for online monitoring of anchor bolt stress while preventing torsional damage to the stress gauge during tensioning. However, this anchor bolt relies on adding grouting and venting components to the outside of the prestressed anchor bolt, achieving anchoring between the prestressed anchor bolt and the rock strata through grouting bonding. Due to insufficient anchoring strength, multiple anchor bolt segments need to be assembled and grouted segmentally, resulting in a large number of components, complex construction procedures, and the inability to utilize mechanical anchor heads to assist in filling deep voids in the anchor hole with grout. Summary of the Invention

[0004] In order to overcome the technical problems described in the background, this application provides a prestressed anchor rod that can optimize the fit between the expansion shell anchor and the grouting structure, simplify the anchor rod construction process, and improve the grouting density of the anchoring section.

[0005] This application provides a prestressed anchor rod, which adopts the following technical solution: A prestressed anchor bolt includes a hollow anchor bolt body, a pad plate, a connector, an expansion shell anchor, and a vent pipe. The hollow anchor bolt body is disposed within a rock borehole, with the end furthest from the borehole opening serving as the output end and the opposite end as the input end. The expansion shell anchor is disposed at the end of the hollow anchor bolt body near the output end. The connector is detachably installed at the end of the hollow anchor bolt body near the input end. The pad plate is disposed on the hollow anchor bolt body, with the connector pressing against the front of the pad plate and the back of the pad plate pressing against the borehole wall. One end of the vent pipe is inserted into the rock borehole, and the other end extends outward. A cement grouting layer is also disposed within the rock borehole.

[0006] By adopting the above technical solution, the hollow anchor bolt body, pad, connector, and expansion shell anchor ensure a firm connection between the anchor bolt and the rock stratum, exhibiting good pull-out resistance and stability, which helps prevent rock stratum sliding or collapse. Furthermore, the detachable connection between the connector and the hollow anchor bolt body makes assembly more convenient, easier to adjust and maintain. The pad increases the contact area between the anchor bolt and the rock stratum, protecting the rock stratum and preventing damage due to stress concentration. The introduction of an vent pipe effectively removes gas from the rock stratum borehole, ensuring the quality of the grouting layer. Simultaneously, the cement grouting layer further enhances the adhesion between the anchor bolt and the rock stratum, improving the overall structural stability. Compared with existing technologies, the anchor bolt of this application can be anchored into the rock stratum borehole more easily and efficiently, while ensuring good installation stability.

[0007] Preferably, the expanding shell anchor includes an expanding shell head and a plug rod. One end of the plug rod is fixed to the output end of the hollow anchor body. A through slot is provided in the middle of the expanding shell head. An elastic piece is installed in the expanding shell head facing the through slot. When the connector is rotated, the hollow anchor body extends into the rock hole. The plug rod passes through the through slot and drives the elastic piece to press the expanding shell head against the hole wall of the rock hole.

[0008] By adopting the above technical solution, the hollow anchor rod body can be inserted into the rock hole by rotating the connector, so that the plug rod passes through the slot of the expansion head, driving the elastic plate to press the expansion head against the hole wall of the rock hole. This mechanism ensures a tight fit between the anchor rod and the rock layer, providing a better fastening effect.

[0009] Preferably, the outer wall of the expansion head is provided with multiple anti-detachment barbs.

[0010] By adopting the above technical solution, the multiple anti-detachment barbs set on the outer wall of the expansion head effectively reduce the anchor rod from falling out of the rock hole when subjected to external force, enhancing the safety and reliability of the anchor rod. At the same time, the design of the anti-detachment barbs also increases the friction between the anchor rod and the rock layer, further improving the stability and pull-out resistance of the anchor rod.

[0011] Preferably, the inner wall of the through slot is provided with a flow guiding surface, which is recessed from the output end to the input end.

[0012] By adopting the above technical solution, the guide surface opened on the inner wall of the through slot can effectively guide the grouting material to flow from the output end to the input end, ensuring the smoothness and uniformity of the grouting process. Through the design of the guide surface, the grouting material can more fully fill the gap between the anchor rod and the rock layer, thereby enhancing the anchoring effect and the stability of the overall structure.

[0013] Preferably, anchoring agent is filled between the connector and the front side of the pad, and between the back side of the pad and the hole wall of the rock stratum.

[0014] By adopting the above technical solution, the anchoring agent is filled between the connector and the pad, and between the pad and the rock stratum hole wall, which can greatly increase the bonding force and friction between the connection interfaces, thereby improving the connection strength and stability of the overall structure. It can also reduce the loosening and slippage of connectors, pads and other components due to vibration or external force during long-term use.

[0015] Preferably, the hollow anchor rod body is a screw rod, the connecting member is a connecting nut, and the hollow anchor rod body and the connecting member are threaded together.

[0016] By adopting the above technical solution, the threaded connection has a certain degree of adjustability, which can adjust the position of the connector on the hollow anchor body according to the actual situation to adapt to different rock strata hole depths and construction requirements. The use of threaded connection enables quick and easy installation and disassembly between the hollow anchor body and the connector, improving construction efficiency and convenience.

[0017] Preferably, the pad includes a mounting part, which is threadedly connected to the hollow anchor rod body.

[0018] By adopting the above technical solution, the threaded connection between the pad installation part and the hollow anchor body can achieve the stable installation of the pad, effectively transfer the prestress of the anchor to the rock borehole wall, and reduce additional fasteners and connection steps through the threaded connection method, making the overall structure simpler.

[0019] Preferably, the pad further includes a flattening part and a connecting part. The connecting part is inclined from the mounting part to the flattening part. Both ends of the connecting part are fixed to the flattening part and the mounting part, respectively. The reverse side of the flattening part presses against the hole wall of the rock stratum hole.

[0020] By adopting the above technical solution, the flattening part design of the pad plate enables it to distribute the force evenly on the rock stratum hole wall when subjected to pressure, which can play a leveling role to a certain extent, thereby making the connection between the connector and the pad plate tighter.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. With the combined action of the hollow anchor body, pad, connector, and expansion shell anchor, a firm connection between the anchor and the rock strata is ensured, which has good pull-out resistance and stability and helps to prevent rock strata from sliding or collapsing. 2. The detachable connection between the connector and the hollow anchor rod body makes assembly more convenient and easier to adjust and maintain; 3. The guide surface opened on the inner wall of the through slot can effectively guide the grouting material to flow from the output end to the input end, ensuring the smoothness and uniformity of the grouting process. Through the design of the guide surface, the grouting material can more fully fill the gap between the anchor rod and the rock layer, thereby enhancing the anchoring effect and the stability of the overall structure. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the prestressed anchor rod in the embodiment of this application.

[0023] Figure 2 This is a schematic diagram showing the state of the prestressed anchor rod installed in the rock strata in the embodiments of this application.

[0024] Explanation of reference numerals in the attached drawings: 1. Hollow anchor body; 2. Pad; 21. Mounting part; 22. Flattening part; 23. Connecting part; 3. Connecting piece; 4. Expanding shell anchor; 41. Expanding shell head; 411. Elastic plate; 412. Anti-loosening barb; 413. Through slot; 414. Guide surface; 42. Insert rod; 5. Exhaust pipe; 6. Cement grouting layer; 7. Rock stratum. Detailed Implementation

[0025] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0026] This application discloses a prestressed anchor rod.

[0027] Reference Figure 1 and Figure 2 A prestressed anchor bolt includes a hollow anchor bolt body 1, a pad 2, a connector 3, an expansion shell anchor 4, and an exhaust pipe 5. A hole is first drilled in the rock stratum 7 to ensure that the verticality of the hole to the rock wall meets the standard. The hole opening is then leveled to ensure the effectiveness of the prestressing application. In this application, the hollow anchor body 1 is installed inside the rock stratum borehole, with the end furthest from the borehole being the output end and the other end being the input end. The expansion shell anchor 4 is installed at the end of the hollow anchor body 1 near the output end. The connector 3 is detachably installed at the end of the hollow anchor body 1 near the input end. The pad 2 is installed on the hollow anchor body 1, so that the connector 3 presses against the front of the pad 2 and the back of the pad 2 presses against the borehole wall of the rock stratum borehole. One end of the exhaust pipe 5 is connected into the rock stratum borehole, and the other end extends outward. A cement grouting layer 6 is also installed inside the rock stratum borehole. The exhaust pipe 5 can discharge air during the grouting process to ensure the grouting quality. This structural combination allows the anchor to better bond with the rock and soil, providing stable anchoring force. The cement grouting layer 6 can fill the gap between the rock stratum borehole and the anchor, enhancing the overall stability.

[0028] Specifically, the hollow anchor body 1 is a screw rod with a threaded structure on its outer surface. The connector 3 is a connecting nut. The hollow anchor body 1 and the connector 3 are threaded together. The threaded connection has a certain degree of adjustability, which can adjust the position of the connector 3 on the hollow anchor body 1 according to the actual situation to adapt to different rock strata hole depths and construction requirements. The use of threaded connection allows for quick and easy installation and disassembly between the hollow anchor body 1 and the connector 3, improving construction efficiency and convenience. In addition, it can also enhance the bonding force with the cement grouting layer 6 to a certain extent.

[0029] In this application, the hollow anchor body 1, as the name suggests, has a hollow cavity that extends through its middle and along its length, so that grout can flow into the rock stratum hole through the hollow part during grouting.

[0030] Furthermore, referring to Figure 1 and Figure 2 The pad 2 includes an mounting part 21, a flattening part 22, and a connecting part 23. The mounting part 21 is a ring structure with internal threads, and its inner diameter is adapted to the outer diameter of the hollow anchor rod body 1. The connecting part 23 is inclined from the mounting part 21 to the flattening part 22, and both ends of the connecting part 23 are fixed to the flattening part 22 and the mounting part 21 respectively, so that the mounting part 21 and the hollow anchor rod body 1 are threadedly connected. The inclined setting of the connecting part 23 in this application can better adapt to the shape of the rock stratum borehole opening, so that the flattening part 22 can fit more closely to the borehole wall. This allows the pressure of the connecting piece 3 to be evenly transmitted to the borehole wall of the rock stratum.

[0031] Furthermore, referring to Figure 1 and Figure 2 The expansion shell anchor 4 includes an expansion shell head 41 and a plug-in rod 42. One end of the plug-in rod 42 is fixed to the output end of the hollow anchor body 1. A discharge groove is also provided along the middle of the plug-in rod 42's length, connecting it to the hollow cavity of the hollow anchor body 1. Furthermore, a through slot 413 is provided in the middle of the expansion shell head 41. A guide surface 414 is provided on the inner wall of the through slot 413, recessed from the output end to the input end. An elastic piece 411 is installed in the expansion shell head 41 facing the through slot 413. The expansion shell head 41 can be a petal-shaped structure made of elastic metal, and the elastic piece 411 can be a spring sheet with good elasticity.

[0032] In practical applications, the user rotates the connector 3, allowing the hollow anchor body 1 to extend into the rock borehole. The insertion rod 42 passes through the through slot 413 and drives the elastic plate 411 to press the expansion head 41 against the borehole wall. When the insertion rod 42 passes through the through slot 413, the elastic plate 411 is compressed and deformed, causing the expansion head 41 to open and press against the borehole wall, thus achieving an anchoring effect. Furthermore, the outer wall of the expansion head 41 is provided with multiple anti-detachment barbs 412. The anti-detachment barbs 412 can be trapezoidal protrusions, which prevent the expansion head 41 from slipping off the rock borehole wall, enhancing the stability of the anchoring. The exhaust pipe 5 can be a plastic hose, with one end connected to the rock borehole and the other end extending outward.

[0033] In this application, grouting is performed on the rock stratum borehole in two ways. In the first case, the rock stratum borehole is located at the bottom, and the installation direction of the anchor rod is consistent with the opening direction of the rock stratum borehole. In this case, grouting is performed through the cavity in the middle of the hollow anchor rod body 1, and then the grout is output from the hollow anchor rod body 1 to the outside, while the gas in the rock stratum borehole is discharged from the exhaust pipe 5. In the second case, the rock stratum borehole is located at the top, and the installation direction of the anchor rod is consistent with the opening direction of the rock stratum borehole. In this case, the hollow anchor rod body 1 and the exhaust pipe 5 switch roles, and grouting is performed through the exhaust pipe 5. Then the grout is output from the exhaust pipe 5 to the outside, while the gas in the rock stratum borehole is discharged from the hollow anchor rod body 1. The guide surface 414 helps the grout to flow better during grouting and fill the gaps around the expansion head 41.

[0034] In this application, the hollow anchor body 1 serves as the main structure, providing support and tensile force transmission for the entire anchor. The expanding shell anchor 4, during anchor installation, expands to tightly bond with the rock borehole wall, providing initial anchoring force. The pad 2 and connector 3 work together, applying prestress by adjusting the tightness of the connector 3, allowing the anchor to better cooperate with the soil and rock mass. The cement grouting layer 6 fills the rock borehole, further enhancing the integrity and stability of the anchor and the soil and rock mass. The vent pipe 5 ensures the smooth progress of the grouting process, while the anchoring agent strengthens the connection between the various components.

[0035] The prestressed anchor bolt in this embodiment, through the synergistic effect of its components, has better anchoring effect, higher stability and stronger adaptability compared with traditional support methods. It can effectively prevent deformation and collapse of the soil and rock mass, and ensure the safety and stability of the project.

[0036] The above are all preferred embodiments of this application. These embodiments are merely explanations of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A prestressed anchor bolt, characterized in that, The device includes a hollow anchor body (1), a pad (2), a connector (3), an expansion shell anchor (4), and an exhaust pipe (5). The hollow anchor body (1) is installed inside a rock hole, with the end away from the rock hole being the output end and the other end being the input end. The expansion shell anchor (4) is installed at the end of the hollow anchor body (1) near the output end. The connector (3) is detachably installed at the end of the hollow anchor body (1) near the input end. The pad (2) is installed on the hollow anchor body (1), and the connector (3) presses against the front of the pad (2), while the back of the pad (2) presses against the wall of the rock hole. One end of the exhaust pipe (5) is connected to the rock hole, and the other end extends outward. A cement grouting layer (6) is also installed inside the rock hole. The expansion shell anchor (4) includes an expansion shell head (41) and a plug rod (42). One end of the plug rod (42) is fixed to the output end of the hollow anchor body (1). A through slot (413) is provided in the middle of the expansion shell head (41). An elastic piece (411) is installed in the expansion shell head (41) facing the through slot (413). When the connector (3) is rotated, the hollow anchor body (1) extends into the rock hole. The plug rod (42) passes through the through slot (413) and drives the elastic piece (411) to press the expansion shell head (41) against the hole wall of the rock hole. The hollow anchor rod body (1) has a hollow cavity through its middle and along its length. The plug rod (42) has a discharge groove through its middle along its length, so that the discharge groove is connected to the hollow cavity of the hollow anchor rod body (1). During grouting, the grout can flow into the rock stratum hole through the hollow cavity and the discharge groove. The hollow anchor rod body (1) is a screw rod, the connecting piece (3) is a connecting nut, and the hollow anchor rod body (1) and the connecting piece (3) are threadedly connected.

2. A prestressed anchor bolt according to claim 1, characterized in that, The outer wall of the expansion head (41) is provided with multiple anti-detachment barbs (412).

3. A prestressed anchor bolt according to claim 2, characterized in that, The inner wall of the through slot (413) is provided with a flow guide surface (414), which is recessed from the output end to the input end.

4. A prestressed anchor bolt according to claim 1, characterized in that, Anchoring agent is filled between the front of the connector (3) and the pad (2), and between the back of the pad (2) and the hole wall of the rock stratum.

5. A prestressed anchor bolt according to claim 4, characterized in that, The pad (2) includes a mounting part (21), which is threadedly connected to the hollow anchor body (1).

6. A prestressed anchor bolt according to claim 5, characterized in that, The pad (2) further includes a flattening part (22) and a connecting part (23). The connecting part (23) is inclined from the mounting part (21) to the flattening part (22). The two ends of the connecting part (23) are fixed to the flattening part (22) and the mounting part (21) respectively. The back of the flattening part (22) presses against the hole wall of the rock stratum hole.

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