A deep foundation pit recoverable anchor cable and a construction method thereof

Abstract

The present application belongs to the technical field of foundation pit support, and provides a deep foundation pit recoverable anchor cable and a construction method thereof, which comprises: a guide cap inside which is divided into a guide cavity and a locking cavity by a partition plate, an eccentric jacking column being arranged in the guide cavity, the jacking column sliding along the axial direction of the guide cap so that the front end of the jacking column penetrates through the partition plate and extends into the locking cavity and is positioned; a pressure bearing structure comprising: a pressure bearing cylinder, an anchor cable clamping piece and a pressing plate, the pressure bearing cylinder being eccentrically arranged in the locking cavity, and one end of the pressure bearing cylinder being fixed on the cavity wall of the locking cavity corresponding to the partition plate, a tapered cavity being formed in the end of the pressure bearing cylinder corresponding to the partition plate to accommodate the anchor cable clamping piece. The present application is simple and fast in installation, and the length remaining outside the anchor device is ensured by the passive self-locking mode of the stress cable, so that the remaining length ensures the effective wedge of the anchor device in the tapered cavity, the full engagement of the anchor device with the stress cable is ensured, the locking force of the stress cable is ensured, and the stress cable is not easy to slip off during the stress test to cause the prestress failure.

Description

Technical Field

[0001] This invention relates to the field of foundation pit support technology, and in particular to a recyclable anchor cable for deep foundation pits and its construction method. Background Technology

[0002] Anchor cables are components inserted into rock masses through holes in weak rock facets during construction, connecting the sliding mass to stable rock layers. They provide suspension and reinforcement, thereby altering the stress state of the slope rock mass. They are typically used in engineering projects where deformation has occurred or where strict deformation control is required. Most traditional anchor cables are permanent, remaining underground after the project is completed, forming long-term underground obstacles that severely hinder secondary development and utilization of the site and pollute the environment.

[0003] To address the issue of traditional anchor cable retention, recyclable anchor cables have emerged on the market. Recyclable anchor cable technology can be categorized into mechanical locking type and thermosetting type, with mechanical locking type being the most widely used. However, the installation process for common mechanical locking type anchor cables is quite cumbersome, and during stress testing, there is a phenomenon where the anchor cable slips out of the anchorage, leading to prestress failure and affecting the project progress.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0005] The purpose of this invention is to provide a recyclable anchor cable for deep foundation pits and its construction method, so as to solve the problems of cumbersome installation process and easy slippage of anchor cables during stress testing.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a recyclable anchor cable for deep foundation pits, comprising: a guide cap internally divided into a guide cavity and a locking cavity by a partition; a top support column eccentrically disposed within the guide cavity, the top support column sliding along the axial direction of the guide cap to allow its front end to penetrate the partition, extend into the locking cavity, and be positioned; a pressure-bearing structure comprising: a pressure-bearing cylinder, an anchor cable clamp, and a pressure plate; the pressure-bearing cylinder being eccentrically disposed within the locking cavity, with one end of the pressure-bearing cylinder corresponding to the partition and fixed to the cavity wall of the locking cavity; a conical cavity formed inward at one end of the pressure-bearing cylinder corresponding to the partition to accommodate the anchor cable clamp, the anchor cable clamp corresponding to the top support column; and an anchor cable clamp formed at the other end of the pressure-bearing cylinder. The perforation allows the stress cable head to pass through and enter the conical cavity. The pressure plate is located between the pressure cylinder and the partition plate. The pressure plate surface has a through hole for the top support column to pass through, and the pressure plate is connected to the anchor cable clamp. By pushing the anchor cable clamp with the stress cable head, the top support column can open the anchor cable clamp, allowing the stress cable to smoothly enter the clamping hole of the anchor cable clamp. The working cable passes through the guide cap, extends into the locking cavity and is centered, so that the working cable head is threadedly fitted with the middle of the pressure plate. By pulling the working cable, the pressure plate can squeeze the anchor cable clamp into the conical cavity, so that the stress cable is passively locked, ensuring that the stress cable head remains outside the anchor cable clamp.

[0007] Preferably, the guide cap corresponding to the guide cavity has a conical cap head on the outside; The inner wall of the locking cavity is provided with guide ridges along the axial direction; The side of the pressure plate is provided with a groove that matches the guide ridge.

[0008] Preferably, the top support column is rectangular, and the end of it extending into the locking cavity is tapered; The top support column has radially extending wing plates on both sides of one end inside the guide cavity.

[0009] Preferably, a compression spring is provided between the wing plate and the partition plate, and the compression spring is sleeved on the outside of the guide rod; One end of the guide rod is fixed to the partition plate, and the other end is fixed to the inclined cavity wall of the guide cavity.

[0010] Preferably, the working cable has a sleeve attached to its head end; The sleeve is provided with external threads, and the diameter of the sleeve is the same as the diameter of the working cable.

[0011] Preferably, a pair of twisted grooves are symmetrically provided on the wall of the sleeve; The twisted groove extends axially to the head end of the sleeve.

[0012] Preferably, a limiting plate is attached to the center of the side of the partition facing the locking cavity; The limiting plate has a hole in the center for the sleeve to pass through.

[0013] Preferably, the limiting plate has a torsion block that elastically protrudes into the hole, and the side of the torsion block facing the sleeve is arc-shaped so that the sleeve can squeeze the torsion block and retract it when passing through the hole. The limiting plate has fins extending from its edge, and the extended ends of the fins are engaged with the side of the top support column located in the guide cavity.

[0014] Preferably, one end of the anchor cable clamp associated pressure plate is provided with a guide groove along its opening direction; One side of the pressure plate associated with the anchor cable clamp is provided with a guide plate along its opening direction; The guide plate is located in the guide slot, which allows the anchor cable clip to be stretched open while moving with the pressure plate. The portions of the stress cable and working cable outside the guide cap are both fitted with protective sleeves.

[0015] A construction method for a recyclable anchor cable in a deep foundation pit, the construction method comprising: step S1, excavation and drilling of the foundation pit; step S2, installation of the anchor cable; step S3, grouting and curing; step S4, tensioning and locking of the anchor cable; and step S5, anchor cable recycling.

[0016] Compared with the closest existing technology, the technical solution of the embodiments of the present invention has the following beneficial effects: The present invention has a simple and quick installation method, and the passive self-locking of the stress cable ensures that the remaining length outside the anchor is retained, thereby preserving a margin to ensure that the anchor forms an effective wedge tightness in the conical cavity, ensuring that the anchor fully engages the stress cable, ensuring the locking force on the stress cable, and making it less likely to slip during stress testing and cause prestress failure. Attached Figure Description

[0017] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a front cross-sectional view of the present invention; Figure 3 for Figure 2 Enlarged view of the internal structure of the guide cap; Figure 4 This is an overall schematic diagram of the anchor cable clip structure of the present invention; Figure 5 This is an overall schematic diagram of the pressure plate structure of the present invention; Figure 6 This is an overall schematic diagram of the limiting plate structure of the present invention; Figure 7 This is a schematic diagram of the overall sleeve structure of the present invention.

[0018] In the diagram: 1. Guide cap; 2. Guide cavity; 3. Locking cavity; 4. Top support column; 5. Partition plate; 6. Pressure bearing cylinder; 7. Anchor cable clamp; 8. Pressure plate; 9. Stress cable; 10. Working cable; 11. Guide rib; 12. Wing plate; 13. Compression spring; 14. Guide rod; 15. Sleeve; 16. Torsion groove; 17. Limiting plate; 18. Torsion block; 19. Wing plate; 20. Guide slot; 21. Guide plate; 22. Sheath. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. Indeed, those skilled in the art will recognize that modifications and variations can be made to the invention without departing from its scope or spirit. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the invention encompass such modifications and variations falling within the scope of the appended claims and their equivalents.

[0020] In the following description, the terms "first / second / third" are used merely to distinguish similar objects and do not represent a specific order of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of the invention described herein can be implemented in an order other than that illustrated or described herein.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing embodiments of this disclosure only and is not intended to limit this disclosure.

[0022] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected," "linked," and "set up" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a direct connection or an indirect connection through intermediate components; a wired connection, a radio connection, or a wireless communication signal connection. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0023] This invention provides a recyclable anchor cable for deep foundation pits and its construction method. It is easy to operate, has stable stress testing, and can ensure effective support for the foundation pit, thus ensuring the quality of engineering construction.

[0024] Example, refer to Figures 1-3 This anchor cable mainly includes a guide cap 1, a pressure-bearing structure, and a working cable 10. The guide cap 1 is divided into a guide cavity 2 and a locking cavity 3 by a partition 5. The guide cap 1 corresponding to the guide cavity 2 has a conical head to facilitate the smooth insertion of the anchor cable into the borehole. Two top support columns 4 are eccentrically arranged inside the guide cavity 2, or more can be evenly distributed. The two top support columns 4 are symmetrically arranged. The top support columns 4 can slide along the axial direction of the guide cap 1 so that the front end of the top support column 4 passes through the partition 5 and extends into the locking cavity 3 for positioning.

[0025] Specifically, the top support column 4 is rectangular, and the end of it that extends into the locking cavity 3 is conical. Both sides of the top support column 4 that is in the guide cavity 2 have radially extending wing plates 12. A compression spring 13 is provided between the wing plate 12 and the partition plate 5. The compression spring 13 is sleeved on the outside of the guide rod 14. When the top support column 4 is positioned, the compression spring 13 is compressed by the wing plate 12. The lower end of the guide rod 14 is welded and fixed to the partition plate 5, and the upper end is correspondingly welded and fixed to the inclined cavity wall of the guide cavity 2.

[0026] The pressure-bearing structure includes: a pressure-bearing cylinder 6, an anchor cable clamp 7, and a pressure plate 8. A pair of pressure-bearing cylinders 6 are eccentrically positioned within the locking cavity 3, and the two pressure-bearing cylinders 6 are arranged symmetrically on the left and right sides. The lower end of the pressure-bearing cylinder 6 is welded and fixed to the bottom cavity wall of the locking cavity 3 corresponding to the partition plate 5. One end of the pressure-bearing cylinder 6 corresponding to the partition plate 5 has a conical cavity opened inward to accommodate the anchor cable clamp 7, and the anchor cable clamp 7 corresponds to the top support column 4. The length of the pressure-bearing cylinder 6 is less than the height of the locking cavity 3, leaving space for the anchor cable clamp 7 to move upward. The anchor cable clamp 7 is bilobed. The lower end of the pressure-bearing cylinder 6 has an anchor cable through hole to allow the head end of the force cable 9 to pass through and enter the conical cavity. Correspondingly, the surface of the guide cap 1 also has a hole similar to the anchor cable through hole. The shaft has a hole, and the pressure plate 8 is located between the pressure cylinder 6 and the partition plate 5. The surface of the pressure plate 8 is provided with a through hole for the top support column 4 to pass through. The diameter of the through hole matches the top support column 4. The inner wall of the locking cavity 3 is welded with a guide rib 11 along the axial direction. The side of the pressure plate 8 is provided with a sliding groove that matches the guide rib 11, thereby restricting the rotation of the pressure plate 8. The anchor cable clamp 7 is pushed by the head end of the stress cable 9 to move towards the partition plate 5. As the anchor cable clamp 7 is displaced, the cone head of the top support column 4 first passes through the through hole on the pressure plate 8 and then enters the clamping hole of the anchor cable clamp 7, thereby opening the anchor cable clamp 7. When the clamping hole of the anchor cable clamp 7 expands to a sufficiently large size, the stress cable 9 enters it and contacts the cone head of the top support column 4.

[0027] Reference Figure 3 , Figure 6 and Figure 7The working cable 10 passes through the bottom of the guide cap 1 and extends into the locking cavity 3, centered thereon, so that the head end of the working cable 10 is threadedly fitted with the middle of the pressure plate 8. By pulling the working cable 10, the pressure plate 8 can squeeze the anchor cable clamp 7 into the conical cavity, thereby passively locking the stress cable 9 and ensuring that the head end of the stress cable 9 remains outside the anchor cable clamp 7. Specifically, the head end of the working cable 10 is connected to a sleeve 15, which is welded or pinned. The sleeve 15 is machined with external threads, and the diameter of the sleeve 15 is the same as the diameter of the working cable 10, ensuring that it can smoothly enter and exit the locking cavity 3; the sleeve 1 A pair of twisted grooves 16 are symmetrically provided on the wall of the tube 5. The twisted grooves 16 extend axially to the head end of the sleeve 15. A limiting plate 17 is attached to the middle of the side of the partition plate 5 facing the locking cavity 3. A hole is opened in the center of the limiting plate 17 to allow the sleeve 15 to pass through. Inside the limiting plate 17, a twisted block 18 elastically protrudes into the hole. A spring groove is provided in the limiting plate 17. A spring is placed horizontally in the groove. The rear end of the twisted block 18 is located in the spring groove. The rear end of the twisted block 18 is radially protruded to prevent it from falling out of the spring groove. Thus, the spring force is used to make the twisted block 18 extend into the hole in the center of the limiting plate 17.

[0028] The side of the twisting block 18 facing the sleeve 15 is arc-shaped so that when the sleeve 15 passes through the hole, it squeezes the twisting block 18 and causes it to retract. When the sleeve 15 is rotated, the twisting groove 16 on its surface will always correspond to the twisting block 18. At that time, the twisting block 18 will automatically spring back into the twisting groove 16, thereby using the sleeve 15 to drive the limiting plate 17 to rotate.

[0029] The edge of the limiting plate 17 extends with a fin 19. The extended end of the fin 19 engages with the side of the top support column 4 located in the guide cavity 2. The top support column 4 has a notch corresponding to the position of the fin 19 to accommodate its movement trajectory. When the fin 19 rotates away from the notch with the limiting plate 17, the top support column 4 is pushed back into the guide cavity 2 by the compression spring 13. The extended end of the fin 19 will not reach the space where the stress cable 9 moves upward, so as not to interfere with the stress cable 9. Therefore, the diameter of the top support column 4 must be larger than the diameter of the stress cable 9 to ensure that the fin 19 can extend into the notch on the top support column 4 to form an engagement.

[0030] To facilitate the removal of stress cable 9 after the prestressing test is completed, refer to... Figures 2-4 In this invention, the pressure plate 8 is connected to the anchor cable clamp 7. Specifically, one end of the anchor cable clamp 7 connected to the pressure plate 8 is provided with a T-shaped guide groove 20 along its opening direction, i.e., the left and right direction. The other side of the pressure plate 8 connected to the anchor cable clamp 7 is provided with a T-shaped guide plate 21 along its opening direction. The guide plate 21 is located in the guide groove 20, so that when the pressure plate 8 moves upward, it can pull the anchor cable clamp 7 to move upward, while not hindering the left and right lobes of the anchor cable clamp 7 from unfolding, thereby releasing the anchor cable clamp 7 and thus pulling the stress cable 9 out of the anchor cable clamp 7 for recycling.

[0031] In this embodiment, the portions of the stress cable 9 and the working cable 10 outside the guide cap 1 are both fitted with PE sheaths 22 or corrugated sleeves 15, and when the working cable 10 is retracted, it is rotated to separate the sleeves 15 from the pressure plate 8 for extraction.

[0032] This invention also provides a construction method for recyclable anchor cables in deep foundation pits. Step S1: Excavation and drilling of the foundation pit. The foundation pit is excavated to the anchor cable construction operating surface, and a drilling rig is used to drill a hole in the soil. Step S2: Installation of the anchor cable. The stress cable and working cable are installed sequentially. After rotating the working cable to ensure the top support column is fully inserted into the guide cavity, the stress cable should be further pushed so that its head contacts the cone head of the top support column. Step S3: Grouting and curing. Cement grout is injected into the hole through the anchor cable grouting pipe. Grouting starts from the bottom of the hole and continues until cement grout overflows from the hole opening. If secondary grouting is required, it can be carried out. Curing is completed when the strength of the grout reaches the design requirements. Step S4: Anchor cable tensioning and locking. After the strength of the grout reaches the design value, the stress cable is tensioned. The anchor cable tensioning load is graded in stages of 10%, 50%, 75%, 100%, and 110%~120%. Step S5: Anchor cable recovery. The working cable is used to move the pressure plate upward to bring the anchor cable clamp out of the conical cavity and pull out the stress cable. Finally, the working cable is rotated to separate the sleeve from the pressure plate and then it can be pulled out.

[0033] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A recyclable anchor cable for deep foundation pits, characterized in that, include: The guide cap is divided into a guide cavity and a locking cavity by a partition. A top support column is eccentrically provided in the guide cavity. The top support column slides along the axial direction of the guide cap so that the front end of the top support column passes through the partition, extends into the locking cavity, and is positioned. The pressure-bearing structure includes: a pressure-bearing cylinder, an anchor cable clamp, and a pressure plate. The pressure-bearing cylinder is eccentrically located in the locking cavity, and one end of the pressure-bearing cylinder is fixed to the cavity wall of the locking cavity corresponding to the partition. The end of the pressure-bearing cylinder corresponding to the partition has a conical cavity to accommodate the anchor cable clamp, and the anchor cable clamp is corresponding to the top support column. The other end of the pressure-bearing cylinder has an anchor cable through hole to allow the stress cable head end to pass through and enter the conical cavity. The pressure plate is located between the pressure-bearing cylinder and the partition. The surface of the pressure plate has a through hole for the top support column to pass through, and the pressure plate is connected to the anchor cable clamp. By pushing the anchor cable clamp with the stress cable head end, the top support column can open the anchor cable clamp so that the stress cable can smoothly enter the clamping hole of the anchor cable clamp. The working cable extends through the guide cap into the locking cavity and is centered, so that the head end of the working cable is threaded into the middle of the pressure plate. By pulling the working cable, the pressure plate can squeeze the anchor cable clamp into the conical cavity, so that the stress cable is passively locked, ensuring that the length of the stress cable head end remains outside the anchor cable clamp.

2. The recyclable anchor cable for deep foundation pits according to claim 1, characterized in that, The guide cap corresponding to the guide cavity has a conical cap head on the outside; The inner wall of the locking cavity is provided with guide ridges along the axial direction; The side of the pressure plate is provided with a groove that matches the guide ridge.

3. The recyclable anchor cable for deep foundation pits according to claim 1, characterized in that, The top support column is rectangular, and one end of it that extends into the locking cavity is tapered; The top support column has radially extending wing plates on both sides of one end inside the guide cavity.

4. The recyclable anchor cable for deep foundation pits according to claim 3, characterized in that, A compression spring is provided between the wing plate and the partition plate, and the compression spring is sleeved on the outside of the guide rod; One end of the guide rod is fixed to the partition plate, and the other end is fixed to the inclined cavity wall of the guide cavity.

5. The recyclable anchor cable for deep foundation pits according to claim 1, characterized in that, The working cable has a sleeve attached to its head end; The sleeve is provided with external threads, and the diameter of the sleeve is the same as the diameter of the working cable.

6. The recyclable anchor cable for deep foundation pits according to claim 5, characterized in that, A pair of twisted grooves are symmetrically provided on the wall of the sleeve; The twisted groove extends axially to the head end of the sleeve.

7. The recyclable anchor cable for deep foundation pits according to claim 6, characterized in that, A limiting plate is attached to the center of the side of the partition facing the locking cavity; The limiting plate has a hole in the center for the sleeve to pass through.

8. The recyclable anchor cable for deep foundation pits according to claim 7, characterized in that, The limiting plate has a torsion block that elastically protrudes into the hole. The side of the torsion block facing the sleeve is arc-shaped so that the sleeve can squeeze the torsion block and retract it when it passes through the hole. The limiting plate has fins extending from its edge, and the extended ends of the fins are engaged with the side of the top support column located in the guide cavity.

9. The recyclable anchor cable for deep foundation pits according to claim 1, characterized in that, One end of the anchor cable clamp associated pressure plate is provided with a guide groove along its opening direction; One side of the pressure plate associated with the anchor cable clamp is provided with a guide plate along its opening direction; The guide plate is located in the guide slot, which allows the anchor cable clip to be opened while moving with the pressure plate. The portions of the stress cable and working cable outside the guide cap are both fitted with protective sleeves.

10. A construction method for recyclable anchor cables in deep foundation pits, characterized in that, The construction method uses the deep foundation pit recyclable anchor cable as described in any one of claims 1-9, and the construction method includes: step S1, foundation pit excavation and drilling; Step S2, install anchor cables; Step S3, grouting and curing; Step S4: Anchor cable tensioning and locking; Step S5: Anchor cable recovery.

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