A pile head reinforcing device for a tubular pile compression static load detection test
By fully welding the annular steel plate to the outer steel plate and using a wire rope tightening structure, the problem of easy slippage and voiding of the pile head during the static load test was solved. This achieved uniform load transfer and adaptive constraint of the pile head, improving the compressive bearing capacity and test stability of the pile head.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FUZHOU RONGJIAN ENG INSPECTION CO LTD
- Filing Date
- 2026-06-11
- Publication Date
- 2026-07-14
AI Technical Summary
In existing technologies, during static load testing of pipe piles, the pile head is prone to relative slippage and local separation, leading to stress concentration and damage such as crushing, bulging, and cracking of the pile head concrete, which affects the safety of testing and the accuracy of data.
The ring-shaped steel plate is fully welded to the outer steel plate and bonded with epoxy resin to form a closed, continuous, rigid load-bearing frame. The uniform load transfer and self-adaptive constraint of the pile head are achieved through the steel wire rope tightening structure and the diagonal bracing mechanism, thus avoiding stress concentration.
It effectively suppresses pile head bulging, splitting, and stress concentration, improves the pile head's compressive bearing capacity and integrity, ensures stable and reliable static load testing, and reduces construction costs.
Smart Images
Figure CN122383029A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of pipe pile fixing technology, and in particular to a pile head reinforcement device for testing the static compressive load of pipe piles. Background Technology
[0002] Because modern buildings are quite tall, they also have high requirements for the bearing capacity of the foundation. Therefore, it is usually necessary to add artificial foundation piles to the foundation; the foundation piles need to be fixed after installation.
[0003] A search revealed Chinese patent document CN221372275U, which discloses a pile head reinforcement device for prestressed concrete pipe piles. The device includes a reinforcing layer, a reinforcement component, a fastening component, and a curing layer. The reinforcing layer is disposed on the outer peripheral wall of the pile head. The reinforcement component is coaxially sleeved on the outside of the pile head. The fastening component locks the reinforcement component to the pile head. The curing layer fills and fixes the space between the reinforcement component and the reinforcing layer. The reinforcing layer initially strengthens the tensile and compressive strength of the pile head. Combined with the reinforcement component sleeved on the pile head, it significantly improves the structural strength of the pile head. During dynamic and static load testing, it effectively prevents deformation of the pile head, ensuring the smooth conduct of the tests. The fastening component secures the reinforcement component, allowing for detachable installation. After the dynamic and static load tests of the pile head are completed, the reinforcement component can be removed and installed on the next pile head, achieving reuse and promoting energy conservation and environmental protection.
[0004] Based on the above search and existing technology findings: the non-integrated structure combining detachable sleeves and fasteners, without a top annular bearing steel plate fully welded to the outer sleeve, cannot form a closed, continuous, and integrally stressed rigid steel frame. Under the condition of large-tonnage progressive loading and long-term load-bearing of the pipe pile, relative slippage and local separation of the sleeve and pile head concrete are likely to occur. The concentrated load of the jack directly acts on the local area of the pile head, causing significant stress concentration, which can easily lead to damage such as crushing, bulging, and cracking of the pile head concrete, making it difficult to ensure the safety and accuracy of static load testing data. Summary of the Invention
[0005] The purpose of this invention is to provide a pile head reinforcement device for static load testing of pipe piles, so as to solve the problems mentioned in the background art.
[0006] The technical solution of the present invention is: a pile head reinforcement device for static load testing of pipe piles, comprising an annular steel plate and an outer steel plate. The outer steel plate is bent and wrapped around the outside of the pipe pile end, and the joints of the outer steel plate are fully welded firmly. The inner diameter of the annular steel plate matches the outer diameter of the high pile head, and its outer diameter is consistent with the outer diameter of the outer steel plate. Epoxy resin is evenly applied to the contact surface between the annular steel plate and the top surface of the high pile head, and epoxy resin is evenly applied to the contact surface between the outer steel plate and the outside of the pipe pile end. The annular steel plate and the outer steel plate are fully welded together.
[0007] The inner side of the outer steel plate has multiple evenly distributed straight grooves, and the central axis of the outer steel plate is parallel to the straight grooves. The outer side of the outer steel plate is provided with a tightening hoop structure, which includes multiple steel wire ropes. Each steel wire rope has a connecting plate welded and fixed at both ends. The two connecting plates on the steel wire ropes are used to fix a rotating cylinder. A fixed shaft is rotatably installed inside the rotating cylinder, and one end of the fixed shaft is fixed to the outer steel plate. A transmission gear is fixed on the outer side of the rotating cylinder and is arranged coaxially with it. The rotating cylinders are linearly distributed, and every two adjacent transmission gears mesh with each other.
[0008] Preferably, the two annular steel plates are provided with multiple annular grooves coaxially arranged with them, and the cross-section of the annular grooves is arc-shaped.
[0009] Preferably, the annular grooves on the two annular surfaces of the annular steel plate are staggered.
[0010] Preferably, the wire rope is made of stainless spring steel.
[0011] Preferably, the outer side of the outer steel plate is provided with multiple T-slots, which are evenly distributed on the outer side of the outer steel plate. The multiple T-slots are aligned with some of the straight grooves one by one. The T-head of the T-slot is concave, and the straight groove is located in the concave part of the T-slot.
[0012] Preferably, a recessed block is slidably inserted into the T-head of the T-slot, and a clamping plate is fixed to the outside of the recessed block, with a steel wire rope passing through each clamping plate.
[0013] Preferably, a first inclined surface is provided on both sides of one end of the straight groove, and a second inclined surface parallel to the first inclined surface is provided on both sides of the recess of the concave block.
[0014] Preferably, multiple outer supports are uniformly fixed to the outer circumference of the outer steel plate, and a diagonal bracing mechanism is connected to the outer side of each outer support.
[0015] Preferably, the diagonal bracing mechanism includes a horizontal shaft, an external threaded rod, and two bearing seats. The two ends of the horizontal shaft are rotatably mounted on the two bearing seats via roller bearings. The horizontal shaft is horizontally positioned, and both bearing seats are fixed to an outer bracket. One end of the external threaded rod is fixed at the middle position of the horizontal shaft. A support cylinder is slidably sleeved on the outer side of the external threaded rod. The inner side of the support cylinder is provided with multiple guide bars that are integral with it and parallel to the central axis. The outer side of the external threaded rod is provided with multiple guide grooves that are adapted to the guide bars, and the guide bars are slidably inserted into the guide grooves. An internal threaded ring is rotatably mounted on one end of the support cylinder, and the internal threaded ring forms a screw connection with the external threaded rod.
[0016] Preferably, an expansion shell is movably embedded in the outer side of the support cylinder. Multiple double-section telescopic cylinders are fixed together between the expansion shell and the support cylinder. A return spring is sleeved on the outer side of the double-section telescopic cylinder. The two ends of the return spring are in contact with the expansion shell and the support cylinder, respectively. A slot is opened on the outer side of the expansion shell. An incomplete ring is set inside the slot. The central angle of the incomplete ring is greater than 90° and less than 180°. The notch of the incomplete ring faces downward. A crossbar is fixed at one end of the incomplete ring. The crossbar passes through the center of the incomplete ring. A rotating rod is fixed at the part of the crossbar located at the center and is coaxial with the center. Both ends of the rotating rod are rotated with the support cylinder. A sliding groove is opened on the outer side of the expansion shell. The rotating rod is located in the sliding groove. A gear is fixed at both ends of the rotating rod and is coaxial with it. A rack that meshes with the gear is fixed inside the expansion shell.
[0017] This invention provides an improved pile head reinforcement device for static load testing of pipe piles, which, compared with the prior art, has the following improvements and advantages: Firstly, this invention forms a closed and continuous rigid load-bearing frame through the overall reinforcement structure of prefabricated pile head, full welding of the outer steel plate, integrated welding of the top annular steel plate, and mechanical interlocking with epoxy resin bonding. This frame can uniformly transmit vertical and horizontal loads, effectively suppress the problems of pile head concrete bulging, splitting, and stress concentration, and significantly improve the compressive bearing capacity and integrity of the pile head. Secondly, the steel wire rope exhibits adaptive expansion and contraction under load, providing secondary flexible constraint on the outer steel plate. This effectively limits bulging, buckling, and weld cracking of the steel plate under heavy static loads, preventing premature failure due to localized stress concentration. Simultaneously, the steel wire rope can be tensioned synchronously with the coordinated deformation of the steel plate and pile head, without generating additional stiffness abrupt changes. This further enhances the overall integrity, anti-burst capability, and safety reserve of the pile head reinforcement system, ensuring a more stable static load testing process. Third, the annular steel plate has evenly distributed annular grooves, and the outer steel plate has vertical grooves. Without reducing the overall structural strength and welding reliability, the annular steel plate and the outer steel plate form an elastic whole that can deform in tandem. Under pressure, it can produce slight bending and radial expansion, releasing stress concentration and preventing the weld from cracking due to excessive rigid constraints. Combined with the adaptive clamping effect of the outer retractable steel wire rope, it achieves rigid bearing, flexible deformation and dual constraints, which greatly improves the stability and durability of the pile head reinforcement structure under large tonnage static loads. Fourth, when the outer steel plate expands radially under load, each wire rope tends to be pushed outward; some wire ropes are driven to rotate by the connecting plate, and the transmission gears on the adjacent rotating drums are linked to drive the remaining wire ropes to be tensioned synchronously; the tensioned wire ropes push the pressure plate to embed into the T-slot, and the concave block on the pressure plate forms a directional extrusion on the straight groove, causing the straight groove section to shrink inward, thereby enabling the outer steel plate to produce an adaptive tightening effect, significantly improving the overall restraint effectiveness; Fifth, the diagonal bracing structure is arranged at multiple points along the circumference of the outer steel plate, which can provide diagonal reinforcement of the outer steel plate of the pile foundation from all directions. The linkage structure of soil loosening triggering the expansion shell to push out and the incomplete ring to screw into the soil achieves adaptive triggering of support anchoring, without the need for manual pre-embedding fixation. The extension length of the diagonal bracing can be flexibly adjusted by the threaded structure to adapt to the ground difference and soil environment of different construction sites. The incomplete ring after anchoring uses the gap to retain soil to improve the grip performance, which greatly improves the pull-out resistance and anti-slip capability of the diagonal bracing mechanism, effectively avoiding the bulging and deformation problems of the outer steel plate of the pile foundation under lateral soil pressure. At the same time, the matching reset spring realizes the automatic reset of the components, which is convenient to disassemble and reusable, reducing the construction cost of pile foundation protection. Attached Figure Description
[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0019] Figure 1 This is a schematic diagram of a tubular three-dimensional structure in the prior art; Figure 2 This is a schematic diagram of the overall installation structure of Embodiment 1 of the present invention; Figure 3 This is a three-dimensional structural diagram of the outer steel plate and the hoop structure in Embodiment 1 of the present invention; Figure 4 This is a front view schematic diagram of the outer steel plate and the hoop structure in Embodiment 1 of the present invention; Figure 5 This is a top view schematic diagram of the outer steel plate and the hoop structure in Embodiment 1 of the present invention; Figure 6 for Figure 5 A magnified structural diagram at point A; Figure 7 This is a top view schematic diagram of the outer steel plate structure in Embodiment 1 of the present invention; Figure 8 for Figure 7 A magnified structural diagram at point B; Figure 9 This is a schematic diagram of the three-dimensional structure of the annular steel plate according to Embodiment 1 of the present invention; Figure 10 This is a schematic cross-sectional view of the annular steel plate structure according to Embodiment 1 of the present invention; Figure 11 This is a schematic diagram of epoxy resin coating according to Embodiment 1 of the present invention; Figure 12 This is a schematic diagram of the overall three-dimensional structure of Embodiment 2 of the present invention; Figure 13 This is a three-dimensional structural diagram of the inclined bracing mechanism according to Embodiment 2 of the present invention; Figure 14 This is a perspective three-dimensional structural diagram of the inclined support mechanism according to Embodiment 2 of the present invention; Figure 15 for Figure 14 A magnified structural diagram at point C; Figure 16 This is a schematic diagram of the three-dimensional structure of the support cylinder according to Embodiment 2 of the present invention; Figure 17 This is a schematic diagram of the three-dimensional structure of the expansion shell in Embodiment 2 of the present invention.
[0020] Figure label: 1. Annular steel plate; 2. Outer steel plate; 3. Epoxy resin adhesive; 4. Steel wire rope; 5. Pressure plate; 6. Fixed shaft; 7. Transmission gear; 8. Rotating cylinder; 9. Connecting plate; 10. Straight groove; 11. Concave block; 12. First inclined surface; 13. T-groove; 14. Second inclined surface; 15. Annular groove; 16. Outer support; 17. Horizontal shaft; 18. External threaded rod; 19. Bearing seat; 20. Roller bearing; 21. Support cylinder; 22. Guide bar; 23. Guide groove; 24. Expansion shell; 25. Internal threaded ring; 26. Return spring; 27. Groove; 28. Incomplete ring; 29. Crossbar; 30. Rotating rod; 31. Actuating gear; 32. Rack. Detailed Implementation
[0021] The present invention will now be described in detail, and the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0022] This invention provides an improved pile head reinforcement device for static load testing of pipe piles. The technical solution of this invention is as follows: Example 1: like Figures 1 to 11 As shown in the figure, this embodiment of the invention provides a pile head reinforcement device for static load testing of pipe piles, including an annular steel plate 1 and an outer steel plate 2. The outer steel plate 2 is bent and wrapped around the outside of the pipe pile end, and the joint of the outer steel plate 2 is fully welded firmly. The inner diameter of the annular steel plate 1 matches the outer diameter of the high pile head, and its outer diameter is consistent with the outer diameter of the outer steel plate 2. Epoxy resin adhesive 3 is evenly applied to the contact surface between the annular steel plate 1 and the top surface of the high pile head, and epoxy resin adhesive 3 is evenly applied to the contact surface between the outer steel plate 2 and the outside of the pipe pile end. The annular steel plate 1 and the outer steel plate 2 are fully welded together.
[0023] As can be seen from the above connection relationship: through full welding and double connection with epoxy resin adhesive 3, the annular steel plate 1, the outer steel plate 2 and the pile head concrete form an integral structure. The adhesive layer is sealed and waterproof, and the bonding is reliable. Welding ensures efficient load transfer and avoids debonding, loosening and local failure.
[0024] Specifically, in conjunction with the appendix Figure 1 and attached Figure 9 As shown, the two annular steel plate 1 has multiple annular grooves 15 arranged coaxially with it on both annular surfaces, and the cross-section of the annular grooves 15 is arc-shaped.
[0025] As can be seen from the above connection relationship, the arc-shaped annular groove 15 can reduce the local stiffness of the annular steel plate 1, so that it can produce a small amount of elastic deformation when under pressure, release stress concentration, and prevent excessive rigidity from causing cracking of the top surface or tearing of the weld.
[0026] Specifically, in conjunction with the appendix Figure 2 Appendix Figure 9 and attached Figure 10 As shown, the annular grooves 15 on the two annular surfaces of the annular steel plate 1 are staggered.
[0027] As can be seen from the above connection relationship, the staggered arrangement of the annular grooves 15 can avoid abrupt changes in stiffness and weak areas of strength, making the annular steel plate 1 more uniform in circumferential stress and deformation, and taking into account both elastic buffering capacity and overall load-bearing safety.
[0028] Specifically, in conjunction with the appendix Figure 7 and attached Figure 8As shown, multiple evenly distributed straight grooves 10 are opened on the inner side of the outer steel plate 2, and the central axis of the outer steel plate 2 is parallel to the straight grooves 10.
[0029] As can be seen from the above connection relationship, the straight groove 10 provides radial deformation space for the outer steel plate 2, so that it can expand outward under pressure and shrink inward under unloading, thereby improving the resistance to splitting and bulging, without reducing the overall vertical bearing capacity.
[0030] Specifically, in conjunction with the appendix Figure 2 Appendix Figure 3 and attached Figure 4 As shown, a tightening structure for tightening is provided on the outer side of the outer steel plate 2. The tightening structure includes multiple steel wire ropes 4. Each steel wire rope 4 has a connecting plate 9 welded and fixed at both ends. The two connecting plates 9 on the steel wire rope 4 are used to fix a rotating cylinder 8. A fixed shaft 6 is rotatably installed inside the rotating cylinder 8, and one end of the fixed shaft 6 is fixed to the outer steel plate 2. A transmission gear 7 is fixed on the outer side of the rotating cylinder 8 and is arranged coaxially with it. The rotating cylinders 8 are linearly distributed, and each pair of adjacent transmission gears 7 meshes with each other.
[0031] As can be seen from the above connection relationship, when the wire rope 4 in a local area is pushed open by the outer steel plate 2, the corresponding rotating cylinder 8 can be rotated through the connecting plate 9, and then the adjacent rotating cylinder 8 can be driven to move synchronously through the meshing transmission gear 7, so as to realize the overall linkage triggered by local deformation, and the adaptive tightening can be completed without all the wire ropes 4 being under force at the same time.
[0032] Specifically, in conjunction with the appendix Figure 2 As shown, the wire rope 4 is made of stainless spring steel.
[0033] As can be seen from the above connection relationship, stainless spring steel has good elasticity and extensibility. It can elastically elongate when under stress and automatically rebound after unloading, continuously providing clamping force. At the same time, it is corrosion-resistant and fatigue-resistant, and is suitable for long-term static load testing conditions.
[0034] Specifically, in conjunction with the appendix Figure 2 - Appendix Figure 8 As shown, multiple T-slots 13 are provided on the outer side of the outer steel plate 2. The multiple T-slots 13 are evenly distributed on the outer side of the outer steel plate 2. The multiple T-slots 13 are aligned with some straight grooves 10 one by one. The T-head of the T-slot 13 is concave, and the straight groove 10 is located in the concave part of the T-slot 13.
[0035] As can be seen from the above connection relationship, the T-groove 13 and the straight groove 10 are precisely aligned, providing directional guidance for the pressing plate 5 and the concave block 11, so that the tightening force is directly applied to the area of the straight groove 10, ensuring that the tightening action is accurate and efficient.
[0036] Specifically, in conjunction with the appendix Figure 2 - Appendix Figure 5As shown, a recess 11 is slidably inserted into the T-head of the T-groove 13, and a clamping plate 5 is fixed on the outside of the recess 11. A steel wire rope 4 passes through each clamping plate 5.
[0037] As can be seen from the above connection relationship, when the wire rope 4 is tightened, it can pull the pressure plate 5 and the concave block 11 to slide directionally along the T-groove 13, converting the tension into an inward compressive force, which is stable, does not deviate, and does not fail.
[0038] Specifically, in conjunction with the appendix Figure 2 - Appendix Figure 8 As shown, a first inclined surface 12 is provided on both sides of one end of the straight groove 10, and a second inclined surface 14 parallel to the first inclined surface 12 is provided on both sides of the recess of the concave block 11.
[0039] As can be seen from the above connection relationship, the two sets of inclined surfaces fit together and can convert the linear extrusion force of the concave block 11 into the inward contraction force on both sides of the straight groove 10, so that the outer steel plate 2 can be tightened quickly and smoothly, thus improving the constraint effect.
[0040] Working principle: When the pile head is subjected to static compressive load, the outer steel plate 2 at a local location undergoes radial expansion, pushing outwards a portion of the steel wire rope 4 in the corresponding area. The pushed-out steel wire rope 4 drives the corresponding rotating cylinder 8 to rotate via the connecting plate 9. Adjacent rotating cylinders 8 achieve linkage through meshing transmission gears 7, thereby driving the remaining steel wire ropes 4 to tighten synchronously. The tightened steel wire rope 4 pulls the pressing plate 5 and the concave block 11 to move inwards along the T-groove 13. The concave block 11 squeezes the straight groove 10 through the inclined surfaces on both sides, causing the area of the straight groove 10 to contract inwards, driving the outer steel plate 2 to produce adaptive tightening. The annular steel plate 1 achieves elastic deformation and stress release through the arc-shaped annular groove 15. Combined with epoxy resin adhesive 3 for bonding and full welding, it forms a composite reinforcement structure with local triggering, linkage tightening, rigid bearing, and elastic buffering, effectively suppressing pile head bulging, splitting, and stress concentration damage, ensuring the stability and reliability of the static load testing process.
[0041] Example 2: Specifically, in conjunction with the appendix Figure 12-17Multiple outer supports 16 are evenly fixed to the outer circumference of the outer steel plate 2, and each outer support 16 is connected to a diagonal bracing mechanism on its outer side. It should be noted that the even distribution of outer supports 16 and diagonal bracing mechanisms on the outer circumference of the outer steel plate 2 can evenly distribute the diagonal bracing support points along the circumference of the pile foundation steel plate, avoiding the concentration of support stress in local steel plate areas and improving the uniformity of stress on the outer steel plate 2. The multi-point diagonal support can distribute the lateral load of the pile foundation from multiple circumferential directions, strengthen the limiting and deformation prevention capabilities of the outer steel plate 2, provide a stable installation base for the subsequent diagonal bracing anchoring structure, and ensure the stability of the overall support structure. The diagonal bracing mechanism includes a horizontal shaft 17, an external threaded rod 18, and two bearing seats 19. The two ends of the horizontal shaft 17 are rotatably mounted through roller bearings 20. The horizontal shaft 17 is horizontally positioned on two bearing seats 19, both bearing seats 19 are fixed to the outer bracket 16, one end of the external threaded rod 18 is fixed at the middle position of the horizontal shaft 17, a support cylinder 21 is slidably sleeved on the outer side of the external threaded rod 18, and multiple guide bars 22 integral with it and parallel to the central axis are provided on the inner side of the support cylinder 21. Multiple guide grooves 23 adapted to the guide bars 22 are opened on the outer side of the external threaded rod 18, and the guide bars 22 are slidably inserted into the guide grooves 23. An internal threaded ring 25 is rotatably installed on one end of the support cylinder 21, and the internal threaded ring 25 forms a screw connection with the external threaded rod 18. It should be further noted that the horizontal shaft 17 achieves the rotation function by relying on the bearing seats 19, which can drive the external threaded rod 18 to make small angle adjustments. It is designed to support different ground inclination angles. The insertion and limiting structure of the guide strip 22 and guide groove 23 restricts the circumferential rotation of the support cylinder 21 relative to the external threaded rod 18, retaining only the axial sliding degree of freedom, ensuring stability and no deviation during the telescopic adjustment process. Relying on the threaded transmission of the internal threaded ring 25 and the external threaded rod 18, rotating the internal threaded ring 25 can drive the axial telescopic extension of the support cylinder 21, which can easily adjust the overall extension length of the inclined bracing mechanism, adapting to ground support points at different distances around the pile foundation, with extremely strong adaptability and adjustment flexibility. An expansion shell 24 is movably embedded on the outside of the support cylinder 21. Multiple double-section telescopic cylinders are fixed together between the expansion shell 24 and the support cylinder 21, and a return spring 26 is sleeved on the outside of the double-section telescopic cylinder. The two ends of the return spring 26 are respectively connected to the expansion shell 24 and the external threaded rod 18. The support cylinder 21 is in contact with the expansion shell 24. A slot 27 is provided on the outer side of the expansion shell 24. An incomplete ring 28 is provided inside the slot 27. The central angle of the incomplete ring 28 is greater than 90° and less than 180°. The notch of the incomplete ring 28 faces downward. A crossbar 29 is fixed at one end of the incomplete ring 28. The crossbar 29 passes through the center of the incomplete ring 28. A rotating rod 30 is fixed at the center of the crossbar 29. Both ends of the rotating rod 30 are rotated with the support cylinder 21. A sliding groove 27 is provided on the outer side of the expansion shell 24. The rotating rod 30 is located in the sliding groove 27. A gear 31 is fixed at both ends of the rotating rod 30 and is coaxial with it. A rack 32 that meshes with the gear 31 is fixed inside the expansion shell 24.It needs further explanation that the double-section telescopic cylinder, together with the return spring 26, constitutes the elastic telescopic component of the expansion shell 24. When compressed, the expansion shell 24 can push outwards, and after the force is released, it automatically retracts thanks to the return spring 26, adapting to the displacement changes of the support surface caused by soil loosening and subsidence; the rack 32 and the actuating gear 31 mesh internally, which can accurately convert the axial telescopic movement of the expansion shell 24 into the rotational movement of the gear, rotating rod 30, and incomplete ring, realizing the linkage and synchronous operation of the shell pushing out and the ring rotating into the soil; the central angle... The core anchoring structure is an incomplete circular ring with a downward-facing notch, ranging from 90° to 180°. This large-radius arc structure significantly increases the contact area with the soil. Combined with the downward-facing notch, the embedded soil can accommodate and store soil, forming a self-locking structure that effectively restrains its own displacement, greatly enhancing the overall diagonal bracing anchoring effect and improving the load-bearing and anti-slip capacity of the diagonal bracing mechanism. The groove 27 provides ample travel for the rotating rod 30, ensuring smooth operation and preventing jamming during the expansion shell 24's extension and contraction and the ring's rotation.
[0042] Working principle: After the pile foundation construction is completed, the diagonal bracing mechanisms on the outer side of the outer steel plate 2 adjust the overall extension length precisely by rotating the inner threaded ring 25 and relying on the threaded engagement between the outer threaded rod 18 and the support cylinder 21, so that the end expansion shell 24 is tightly pressed against the surface of the soil around the pile foundation, completing the initial support positioning. When the soil around the pile foundation becomes loose or settles due to the load, the reverse squeezing force generated by the loose soil will push the expansion shell 24 outward, compressing the double-section telescopic cylinder and the return spring 26. During the axial outward movement of the expansion shell 24, the rack 32 fixed on its inner side is simultaneously displaced, driving the two-sided gear 31 to rotate through internal meshing transmission, driving the coaxial rotating rod 30 and crossbar 29 to rotate in linkage, thereby precisely driving the incomplete circular ring with the notch facing downward in the groove 27 to rotate and cut into the surrounding loose soil. After the incomplete circular ring is screwed into the soil, the downward-facing gap will actively fill the accumulated soil, forming a self-locking anchoring structure. This completely restricts the ring's retraction and slippage, greatly enhancing anchoring stability and effectively increasing the overall diagonal bracing strength. It continuously provides strong diagonal support to the outer steel plate 2 of the pile foundation, offsetting the lateral squeezing force of the surrounding soil on the steel plate and preventing deformation and bulging. As the surrounding soil gradually compacts and stabilizes, and the lateral squeezing force decreases, the return spring 26 releases its elasticity to push the double-section telescopic cylinder to return to its original position, causing the expansion shell 24 to retract inward. Simultaneously, through the reverse transmission of the gear and rack 32, the incomplete circular ring rotates and retracts, achieving automatic structural reset. This facilitates subsequent overall disassembly and reuse.
[0043] The foregoing description enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A pile head reinforcement device for static load testing of pipe piles, comprising an annular steel plate (1) and an outer steel plate (2), characterized in that: The outer steel plate (2) is bent and wrapped around the outside of the pipe pile end, and the joint of the outer steel plate (2) is fully welded. The inner diameter of the ring steel plate (1) matches the outer diameter of the high pile head, and its outer diameter is consistent with the outer diameter of the outer steel plate (2). The contact surface between the ring steel plate (1) and the top surface of the high pile head is evenly coated with epoxy resin adhesive (3). The contact surface between the outer steel plate (2) and the outside of the pipe pile end is evenly coated with epoxy resin adhesive (3). The ring steel plate (1) and the outer steel plate (2) are fully welded together. The inner side of the outer steel plate (2) has multiple evenly distributed straight grooves (10), and the central axis of the outer steel plate (2) is parallel to the straight grooves (10); The outer side of the outer steel plate (2) is provided with a tightening hoop structure, which includes multiple steel wire ropes (4). Each steel wire rope (4) has a connecting plate (9) welded and fixed at both ends. The two connecting plates (9) on the steel wire rope (4) are fixed together with a rotating cylinder (8). A fixed shaft (6) is rotatably installed inside the rotating cylinder (8), and one end of the fixed shaft (6) is fixed on the outer steel plate (2). A transmission gear (7) is fixed on the outer side of the rotating cylinder (8) and is coaxially arranged with it. Each rotating cylinder (8) is linearly distributed, and each two adjacent transmission gears (7) mesh with each other.
2. The pile head reinforcement device for static load testing of pipe piles according to claim 1, characterized in that: The two annular steel plate (1) has multiple annular grooves (15) arranged coaxially with it on both annular surfaces, and the cross-section of the annular grooves (15) is arc-shaped.
3. The pile head reinforcement device for static load testing of pipe piles according to claim 2, characterized in that: The annular steel plate (1) has annular grooves (15) staggered on its two annular surfaces.
4. The pile head reinforcement device for static load testing of pipe piles according to claim 1, characterized in that: The wire rope (4) is made of stainless spring steel.
5. The pile head reinforcement device for static load testing of pipe piles according to claim 1, characterized in that: The outer side of the outer steel plate (2) is provided with multiple T-shaped grooves (13). The multiple T-shaped grooves (13) are evenly distributed on the outer side of the outer steel plate (2). The multiple T-shaped grooves (13) are aligned with some straight grooves (10). The T-head of the T-shaped groove (13) is concave, and the straight groove (10) is located in the concave part of the T-shaped groove (13).
6. The pile head reinforcement device for static load testing of pipe piles according to claim 5, characterized in that: A recess (11) is slidably inserted into the T-head of the T-groove (13), and a clamping plate (5) is fixed on the outside of the recess (11). A steel wire rope (4) passes through each clamping plate (5).
7. The pile head reinforcement device for static load testing of pipe piles according to claim 6, characterized in that: The straight groove (10) has a first inclined surface (12) on both sides of one end, and the concave block (11) has a second inclined surface (14) on both sides of the concave opening that is parallel to the first inclined surface (12).
8. The pile head reinforcement device for static load testing of pipe piles according to claim 1, characterized in that: The outer circumference of the outer steel plate (2) is uniformly fixed with multiple outer supports (16), and each outer support (16) is connected to a diagonal bracing mechanism on its outer side.
9. A pile head reinforcement device for static load testing of pipe piles according to claim 8, characterized in that: The inclined support mechanism includes a horizontal shaft (17), an external threaded rod (18), and two bearing seats (19). The two ends of the horizontal shaft (17) are rotatably mounted on the two bearing seats (19) through roller bearings (20). The horizontal shaft (17) is horizontally arranged. The two bearing seats (19) are fixed on the outer bracket (16). One end of the external threaded rod (18) is fixed at the middle position of the horizontal shaft (17). A support cylinder (21) is slidably sleeved on the outer side of the external threaded rod (18). Multiple guide bars (22) with an integral structure and parallel to the central axis are provided on the inner side of the support cylinder (21). Multiple guide grooves (23) adapted to the guide bars (22) are opened on the outer side of the external threaded rod (18). The guide bars (22) are slidably inserted into the guide grooves (23). An internal threaded ring (25) is rotatably installed on one end of the support cylinder (21). The internal threaded ring (25) and the external threaded rod (18) form a screw connection.
10. A pile head reinforcement device for static load testing of pipe piles according to claim 9, characterized in that: An expansion shell (24) is movably embedded in the outer side of the support cylinder (21). Multiple double-section telescopic cylinders are fixed together between the expansion shell (24) and the support cylinder (21). A return spring (26) is sleeved on the outer side of each double-section telescopic cylinder. The two ends of the return spring (26) are in contact with the expansion shell (24) and the support cylinder (21), respectively. A slot (27) is opened on the outer side of the expansion shell (24). An incomplete circular ring (28) is provided inside the slot (27). The central angle of the incomplete circular ring (28) is greater than 90° and less than 180°. The notch of the incomplete circular ring (28) faces downwards. One end of the ring (28) is fixed with a crossbar (29), which passes through the center of the incomplete ring (28). The crossbar (29) is partially fixed with a rotating rod (30) coaxial with the center. Both ends of the rotating rod (30) are rotated with the support cylinder (21). The outer side of the expansion shell (24) is provided with a sliding groove (27). The rotating rod (30) is located in the sliding groove (27). Both ends of the rotating rod (30) are fixed with a gear (31) coaxial with it. The inside of the expansion shell (24) is fixed with a rack (32) that meshes with the gear (31).