Prestressed tensile shear multi-joint PHC pile connecting structure and construction method

Abstract

This invention discloses a prestressed tensile-shear multi-joint PHC pile connection structure and construction method, belonging to the field of PHC pile connection technology. It includes multiple PHC pipe piles and a pile cap foundation. A fixing lock head connection device is pre-embedded at the root of the bottom PHC pipe pile, with the bottom end connected to a steel pile tip. A prestressed steel strand assembly passes through the interior of multiple PHC pipe piles and is used in conjunction with the lock head connection device. The lock head connection device includes an anchor ring pre-embedded at the root of the bottom PHC pipe pile, with two symmetrical baffles at the bottom of the anchor ring. A V-groove is formed in the middle of the anchor ring, with a locking hole at the bottom of the V-groove. The prestressed steel strand assembly includes a steel strand bundle, one end of which passes through the anchor ring pad and the upper anchor ring, and the other end is fixedly connected to a pointed lock head. A positioning plate is also provided, which can drive the pointed lock head through the locking hole. The positioning plate can drive the pointed lock head vertically down until it passes through the locking hole, enabling the steel strand bundle to be connected inside the PHC pipe pile after the multiple PHC pipe piles are connected, avoiding damage to the steel strand bundle during pile driving.

Description

Technical Field

[0001] This invention belongs to the field of PHC pile connection technology, specifically relating to a prestressed tensile-shear multi-joint PHC pile connection structure and construction method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] PHC pipe piles (high-strength concrete pipe piles) are more efficient, faster to construct, and consume fewer resources than bored cast-in-place piles. However, for multi-segment connected long PHC pipe piles, the quality of on-site welding at the joints is difficult to guarantee, and the connection method itself has poor ductility. Therefore, they are prone to exhibiting brittle characteristics when subjected to large tensile and shear forces.

[0004] In the prior art, patent CN106801428A discloses a reinforced tensile-shear PHC pipe pile foundation structure and its construction method, which connects PHC pipe piles by prestressed steel strands and expands the contact area between the top of the pile and the foundation cap to enhance the connection strength between PHC pipe piles.

[0005] However, the above scheme has the following problems: during construction, the prestressed steel strands need to be placed in the PHC pipe piles before the piles are driven, which can easily lead to damage to the prestressed steel strands and make them unsuitable for tensioning and stress; and the measures for fixing the prestressed steel strands in the PHC pipe piles are unstable, and the failure of the hinge may cause the prestressed steel strands to detach from the anchor plate. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a prestressed tensile-shear multi-joint PHC pile connection structure and construction method. By setting a positioning plate to clamp the pointed lock head through the lock hole, the steel strand bundle can be connected inside the PHC pipe pile after multiple PHC pipe piles are connected, avoiding damage to the steel strand bundle during pile driving. After the pointed lock head passes through the lock hole and rotates 90°, the anchor ring abuts against the pointed lock head, preventing the steel strand bundle from detaching from the anchor ring.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first aspect provides a prestressed tensile-shear multi-joint PHC pile connection structure, including multiple PHC pipe piles and a pile cap foundation. The PHC pipe piles include prestressed steel bars and high-strength concrete. Pipe pile sleeves and pipe pile end plates are provided at the top and bottom of the PHC pipe piles. A fixing lock head connection device is pre-embedded at the root of the bottom PHC pipe pile, and the bottom end is connected to the steel pile tip. The prestressed steel strand kit passes through the interior of multiple PHC pipe piles and is used in conjunction with the lock head connection device.

[0009] The locking head connection device includes an anchor ring pre-embedded at the root of the PHC pipe pile at the bottom. Two symmetrical baffles are set at the bottom of the anchor ring, and a V-groove is opened in the middle of the anchor ring. A locking hole is opened at the bottom of the V-groove.

[0010] The prestressed steel strand kit includes a bundle of steel strands, one end of which passes through the anchor ring pad and the upper anchor ring, and the other end is fixedly connected to a pointed lock head; a positioning plate is also provided, which can drive the pointed lock head through the lock hole.

[0011] Preferably, a hollow sleeve is installed inside the upper PHC pipe pile, and a ring-shaped sealing plate is fixedly connected to the bottom end of the hollow sleeve; an anchor ring pad is provided at the top of the hollow sleeve, the top of the anchor ring pad is flush with the top of the foundation, and an upper anchor ring is provided at the top of the anchor ring pad; a reinforcing bar is fixedly connected to the outer wall of the top of the hollow sleeve and tied together with the steel mesh of the foundation.

[0012] Preferably, an annular connecting plate is welded to the top end plate of the upper PHC pipe pile, and multiple fixing blocks are arranged in a circumferential array on the upper part of the connecting plate. Mechanical connecting sleeves are fixedly installed inside the fixing blocks, and the mechanical connecting sleeves are connected to anchoring steel bars.

[0013] Preferably, the pointed lock head includes a cylindrical cone, on which symmetrical auxiliary plates are provided, and the shape of the lock hole matches the shape of the pointed lock head.

[0014] Preferably, the positioning disk includes a cylindrical counterweight disk, with a V-shaped protrusion fixedly connected to the bottom of the cylindrical counterweight disk, and the V-shaped protrusion can be placed into a V-groove; a wire harness through hole is provided at the center of the positioning disk, and a first groove is provided on both sides vertically to the top surface of the positioning disk, the bottom of the first groove is connected to a second groove horizontally, and the second groove is not connected to the wire harness through hole; above the second groove, the first groove is connected to a third groove horizontally, and the third groove is connected to the wire harness through hole; the bottom of the second groove is connected to a fourth groove vertically, and a spring pin hole is opened on the bottom side of the fourth groove near the wire harness through hole.

[0015] Preferably, a linkage mechanism is provided inside the positioning disk. The linkage mechanism includes a first rod in the first groove, a second rod in the second groove, a third rod in the third groove, and a spring pin in the fourth groove. One end of the second rod is fixedly connected to the first rod, and the other end is connected to a spring, which abuts against the inner wall of the second groove away from the first groove. One end of the third rod is fixedly connected to the first rod, and the other end extends out of the third groove and connects to the extrusion plate. The spring pin is fixedly connected to the second rod with the pin head facing downward.

[0016] Preferably, the PHC pipe pile has corresponding grooves inside, and the side wall of the positioning plate has protrusions that can be inserted into the grooves. The outer diameter of the positioning plate matches the inner diameter of the PHC pipe pile.

[0017] Secondly, a construction method for a prestressed tensile-shear multi-joint PHC pile connection structure is provided, the specific steps of which include:

[0018] All PHC pipe piles are driven into the formation. Then, the pointed lock head is placed in the positioning plate and clamped by the extrusion plate. The other end of the steel strand bundle passes through the hollow sleeve first, and then through the anchor ring pad and the upper anchor ring.

[0019] Insert the protrusion of the positioning plate into the groove inside the PHC pipe pile, place the positioning plate inside the PHC pipe pile, and let it slide down a certain distance to reserve the position for installing the hollow sleeve.

[0020] Hollow sleeves are installed inside the upper PHC pipe piles, and annular connecting plates are welded to the top pipe pile end plates and anchoring steel bars are installed; anchor ring pads and upper anchor rings are set at the top of the hollow sleeves; and the foundation steel mesh is tied.

[0021] Continue releasing the steel strand bundle, causing the V-bump to fall into the V-groove, the spring pin head to be pressed back into the spring pin hole, the spring to push the second rod to move the extrusion plate away from the pointed lock head, and the pointed lock heads 1-4 to be released and fall through the lock hole;

[0022] Rotate the steel strand bundle 90° to turn the pointed lock head, then tighten the steel strand bundle; then pour concrete.

[0023] After the foundation is properly cured, prestress is applied to one end of the steel strand bundle located at the upper anchor ring. Once the design standard value is reached, an overall prestressed system is formed, and then the anchor is sealed.

[0024] Preferably, when driving all PHC pipe piles into the stratum, first weld and fix the steel pile tip at the bottom end of the bottom PHC pipe pile, and then drive the bottom end of the bottom PHC pipe pile into the stratum; then align the bottom end plate of the PHC pipe pile to be driven with the top end plate of the PHC pipe pile driven into the stratum, and weld them together as one piece. After cleaning the weld and applying anti-corrosion material to the connection, continue driving the piles.

[0025] Preferably, when the PHC pipe pile to be driven is aligned with the PHC pipe pile driven into the stratum, the grooves need to be aligned vertically.

[0026] Compared with the prior art, the advantages and positive effects of this invention are:

[0027] This invention features a positioning disc with a pressing plate that clamps the pointed locking head, causing it to fall vertically until it passes through the locking hole. This allows the steel strand bundle to be connected to the inside of the PHC pipe pile after multiple PHC pipe piles are connected, preventing damage to the steel strand bundle during pile driving. After the pointed locking head passes through the locking hole, it rotates 90° to make the anchor ring abut against the pointed locking head, preventing the steel strand bundle from detaching from the anchor ring. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, 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 improper limitation of the invention.

[0029] Figure 1 This is an overall schematic diagram of the connection structure of Embodiment 1 or Embodiment 2 of the present invention;

[0030] Figure 2 This is Embodiment 1 or Embodiment 2 of the present invention. Figure 1 Enlarged view of point A;

[0031] Figure 3 This is Embodiment 1 or Embodiment 2 of the present invention. Figure 1 Enlarged view of point B;

[0032] Figure 4 This is Embodiment 1 or Embodiment 2 of the present invention. Figure 1 Enlarged view of point C;

[0033] Figure 5 This is Embodiment 1 or Embodiment 2 of the present invention. Figure 1 Enlarged view of point D;

[0034] Figure 6 This is a schematic diagram of the anchor ring of Embodiment 1 or Embodiment 2 of the present invention;

[0035] Figure 7 This is a cross-sectional schematic diagram of the slotted positioning disk in Embodiment 1 or Embodiment 2 of the present invention;

[0036] Figure 8 This is a cross-sectional schematic diagram of the positioning disk mounting linkage mechanism of Embodiment 1 or Embodiment 2 of the present invention;

[0037] Figure 9 This is Embodiment 1 or Embodiment 2 of the present invention. Figure 1 EE cross-sectional schematic diagram;

[0038] In the picture:

[0039] 1. Prestressed steel strand assembly; 1-1. Upper anchor ring; 1-2. Anchor ring pad; 1-3. Steel strand bundle; 1-4. Pointed lock head; 2. PHC pipe pile; 2-1. High-strength concrete; 2-2. Prestressed steel reinforcement; 2-3. Pipe pile sleeve; 2-4. Pipe pile end plate; 2-5. Hollow sleeve; 2-6. Annular sealing plate; 2-5. Reinforcing rib; 2-7. Fixing block; 2-8. Anchoring reinforcement; 2-9. Groove; 3. Lock head connecting device; 3-1. Anchor ring; 3-2. Baffle; 3-3. V-groove; 3-4, Locking hole; 3-5, Positioning plate; 3-6, Cylindrical counterweight plate; 3-7, V-protrusion; 3-8, Wire harness through hole; 3-9, First groove; 3-10, Second groove; 3-11, Third groove; 3-12, Fourth groove; 3-13, Spring pin hole; 3-14, First rod; 3-15, Second rod; 3-16, Spring; 3-17, Third rod; 3-18, Extrusion plate; 3-19, Spring pin; 3-20, Handle; 3-21, Protrusion; 4, Steel pile tip; 5, Foundation cap. Detailed Implementation

[0040] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, 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 invention pertains.

[0041] The present invention will now be described in detail with reference to the accompanying drawings.

[0042] Example 1

[0043] This embodiment discloses a prestressed tensile-shear multi-joint PHC pile connection structure, such as... Figure 1 As shown, it includes multiple PHC pipe piles 2, with a locking head connection device 3 pre-embedded and fixed at the root of the bottom PHC pipe pile 2; the prestressed steel strand kit 1 passes through the interior of multiple PHC pipe piles and is used in conjunction with the locking head connection device 3; the bottom end of the bottom PHC pipe pile is fixedly connected to the steel pile tip 4.

[0044] The steel pile tip 4 has three structural forms: open type, cross-shaped closed type, and conical closed type. The choice of steel pile tip 4 structure is based on the local soil conditions, and it plays a guiding and penetrating role as a whole; the conical closed type is used in this embodiment. The PHC pipe pile 2 is driven into the ground by static pressure or hammer driving.

[0045] like Figure 4 As shown, the PHC pipe pile 2 includes prestressed steel bars 2-2 and high-strength concrete 2-1. The top and bottom ends of the PHC pipe pile 2 are equipped with pipe pile sleeves 2-3 and pipe pile end plates 2-4. When connecting PHC pipe piles 2, the pipe pile end plates 2-4 of the two PHC pipe piles are aligned and then mechanically connected into one piece by welding or conical connection.

[0046] like Figure 5 , Figure 6 As shown, the locking head connecting device 3 includes an anchor ring 3-1, with two symmetrical baffles 3-2 at the bottom of the anchor ring. A V-groove 3-3 is formed in the middle of the anchor ring 3-1, and a locking hole 3-4 is formed at the bottom of the V-groove 3-3. The anchor ring 3-1 is pre-embedded at the root of the PHC pipe pile 2 at the bottom. The diameter of the anchor ring 3-1 is larger than the inner diameter of the PHC pipe pile but smaller than its outer diameter. Specifically, several reinforcing bar holes are provided on the anchor ring 3-1. These holes are arranged in a circular array around the center of the anchor ring 3-1 at the top of the anchor ring 3-1. The prestressed reinforcing bars 2-2 of the PHC pipe pile 2 pass through the reinforcing bar holes and are then cast together into the PHC pipe pile, becoming an integral part of the pre-embedded reinforced concrete, thus providing compressive strength and fixation.

[0047] like Figure 1 , Figure 2 , Figure 5 As shown, the prestressed steel strand assembly 1 includes an upper anchor ring 1-1, which is positioned above the anchor ring pad 1-2. One end of the steel strand bundle 1-3 passes through the anchor ring pad 1-2 and the upper anchor ring 1-1, while the other end is fixedly connected to a pointed lock head 1-4. The pointed lock head 1-4 includes a cylindrical cone with symmetrical auxiliary plates on it. The shape of the lock hole 3-4 matches the shape of the pointed lock head 1-4.

[0048] In this embodiment, the steel strand bundle 1-3 is threaded through the interior of multiple PHC pipe piles 2. After the pointed lock head 1-4 passes through the lock hole 3-4, the steel strand bundle 1-3 is rotated so that the pointed lock head 1-4 touches the baffle 3-2, and then the steel strand bundle 1-3 is tightened.

[0049] After multiple PHC pipe piles are connected, steel strand bundles 1-3 are then threaded through the PHC pipe piles. Since the steel strand bundles 1-3 have weight, while the weight of the pointed lock head 1-4 is limited, it is difficult to ensure that the pointed lock head 1-4 falls vertically into the lock hole 3-4 without wobbling. To ensure that the pointed lock head 1-4 can accurately fall into the lock hole 3-4 after the steel strand bundles 1-3 are threaded through the PHC pipe piles, a positioning disc 3-5 is provided in this embodiment.

[0050] Specifically, such as Figure 5 , Figure 7 , Figure 8 As shown, the positioning disk 3-5 includes a cylindrical counterweight disk 3-6, with a V-shaped protrusion 3-7 fixedly connected to the bottom of the cylindrical counterweight disk 3-6. The V-shaped protrusion 3-7 matches the size of the V-groove 3-3, and the V-shaped protrusion 3-7 can be inserted into the V-groove 3-3. A wire harness through hole 3-8 is provided in the center of the positioning disk 3-5, and a pointed locking head 1-4 can pass through the wire harness through hole 3-8.

[0051] Centered on the wire harness through hole 3-8, vertical first grooves 3-9 are provided on both sides of the positioning plate 3-5. The top of the first groove 3-9 connects to the top surface of the positioning plate 3-5, and the bottom of the first groove 3-9 connects to the horizontal second groove 3-10. The second groove 3-10 is not connected to the wire harness through hole 3-8. Above the second groove 3-10, the first groove 3-9 connects to the horizontal third groove 3-11, which is connected to the wire harness through hole 3-8. The bottom of the second groove 3-10 connects to the vertical fourth groove 3-12. A spring pin hole 3-13 is opened on the bottom side of the fourth groove 3-12 near the wire harness through hole 3-8. The fourth groove 3-12 is partially connected to the bottom surface of the positioning plate 3-5 through the spring pin hole 3-13.

[0052] A linkage mechanism is provided within the positioning disc 3-5. Specifically, the linkage mechanism includes a first rod 3-14 slidably disposed within the first groove 3-9, and a second rod 3-15 slidably disposed within the second groove 3-10. One end of the second rod 3-15 is fixedly connected to the first rod 3-14, and the other end is connected to a spring 3-16, which abuts against the inner wall of the second groove 3-10 away from the first groove 3-9. A third rod 3-17 slidably disposed within the third groove 3-11, one end of which is fixedly connected to the first rod 3-14, and the other end extends through the third groove and is fixedly connected to a pressing plate 3-18 within the wire harness through hole 3-8. It also includes a spring pin 3-19 disposed within the fourth groove 3-12, which is fixedly connected to the second rod 3-15, with the pin head of the spring pin facing downwards. A handle 3-20 is fixedly connected to the end of the first rod 3-14 located in the first groove 3-9.

[0053] The operator holds the handles 3-20 on both sides and pushes the first rods 3-14 on both sides toward the wire harness through hole 3-8, causing the pressing plates 3-18 on both sides to move toward the wire harness through hole 3-8. At the same time, the second rod 3-15 will press the spring 3-16, causing the spring pin 3-19 to move toward the spring pin hole 3-13. When the pin head of the spring pin 3-19 reaches the spring pin hole 3-13 and pops out, the operator releases the handles 3-20, and the pressing plate 3-18 is fixed in position to clamp the pointed lock head 1-4.

[0054] Understandably, the distance between the compression plates 3-18 can be reserved according to the actual size of the pointed lock heads 1-4.

[0055] It is easy to understand that the positioning disc 3-5 is heavier than the pointed lock head 1-4, and the outer diameter of the positioning disc 3-5 matches the inner diameter of the PHC pipe pile 2. The positioning disc 3-5 drives the pointed lock head 1-4 to fall vertically until it contacts the lock head connecting device 3.

[0056] like Figure 9As shown, to ensure that the V-shaped protrusion 3-7 of the positioning disc 3-5 falls into the V-groove 3-3, a corresponding groove 2-9 is provided inside the PHC pipe pile, and a protrusion 3-21 is provided on the side wall of the positioning disc 3-5. The protrusion is inserted into the groove to prevent the positioning disc 3-5 from rotating inside the PHC pipe pile, thus allowing the V-shaped protrusion 3-7 of the positioning disc 3-5 to fall into the V-groove 3-3. When the V-shaped protrusion 3-7 of the positioning disc 3-5 falls into the V-groove 3-3, under the action of gravity, the pin head of the spring pin 3-19 is pressed back into the spring pin hole 3-13, the spring 3-16 pushes the second rod 3-15 away, and at the same time, the pressing plate 3-18 moves away from the pointed lock head 1-4. The pointed lock head 1-4 is released and can fall directly through the lock hole 3-4.

[0057] In some implementations, multiple rollers can be arrayed on the circumference of the positioning disk 3-5 to facilitate the downward sliding of the positioning disk 3-5 along the interior of the PHC pipe pile 2.

[0058] like Figure 2 , Figure 3 As shown, a hollow sleeve 2-5 is installed inside the upper PHC pipe pile 2, and a ring-shaped sealing plate 2-6 is fixedly connected to the bottom end of the hollow sleeve 2-5. An anchor ring plate 1-2 is installed on the top of the hollow sleeve 2-5, and the top of the anchor ring plate 1-2 is flush with the top of the foundation. An upper anchor ring is installed on the top of the anchor ring plate 1-2. A reinforcing rib 2-51 is fixedly connected to the outer wall of the top of the hollow sleeve and tied together with the steel mesh of the foundation 5. During pouring, the space between the inside of the PHC pipe pile 2 and the hollow sleeve 2-5 is poured, and then the hollow sleeve 2-5 and the foundation 5 are poured together.

[0059] It is important to note that before pouring, an annular connecting plate needs to be welded to the end plate of the upper PHC pipe pile 2. Multiple fixing blocks 2-7 are arranged in a circular array on the upper part of the connecting plate. Mechanical connecting sleeves are fixed inside the fixing blocks 2-7, and the fixing blocks 2-7 are connected to the anchoring steel bars 2-8 through the mechanical connecting sleeves. The anchoring steel bars 2-8 are poured together with the foundation 5. The bent anchor portion of the anchoring steel bars 2-8 faces outwards.

[0060] In this embodiment, after the foundation 5 is properly cured, prestress is applied to one end of the steel strand bundle 1-3 located on the anchor ring pad 1-2 and the upper anchor ring 1-1. After reaching the design standard value, an overall prestressed system is formed, and then the anchor is sealed.

[0061] The aforementioned PHC pipe pile 2 and hollow sleeves 2-5 are all prefabricated in advance at the prefabrication plant.

[0062] Example 2

[0063] This embodiment discloses a construction method for a prestressed tensile-shear multi-joint PHC pile connection structure, which applies a prestressed tensile-shear multi-joint PHC pile connection structure from Embodiment 1. The specific steps include:

[0064] Weld and fix the steel pile tip at the bottom end of the PHC pipe pile 2, and then drive the bottom end of the PHC pipe pile 2 into the stratum. Next, align the bottom end pipe pile plate 2-4 of the PHC pipe pile 2 to be driven into the stratum with the top end pipe pile plate 2-4 of the PHC pipe pile 2 driven into the stratum, and weld them together. Then clean the weld and apply anti-corrosion material to the connection, and then drive the pile.

[0065] Understandably, when aligning PHC pipe piles 2, the grooves need to be aligned vertically.

[0066] After all the PHC pipe piles 2 have been driven into the formation, the pointed lock head 1-4 is placed in the positioning plate 3-5 and clamped by two extrusion plates 3-18. The other end of the steel strand bundle 1-3 first passes through the hollow sleeve 2-5, and then through the anchor ring pad 1-2 and the upper anchor ring 1-1.

[0067] Insert the protrusion of positioning disc 3-5 into the groove inside PHC pipe pile 2, place positioning disc 3-5 into PHC pipe pile 2, and let it slide down a certain distance to reserve the position for installing hollow sleeve 2-5.

[0068] Then, a hollow sleeve 2-5 is installed inside the upper PHC pipe pile 2, and a ring-shaped connecting plate is welded to the top pipe pile end plate, and anchor steel bars 2-8 are installed; anchor ring pads 1-2 and upper anchor rings 1-1 are set on the top of the hollow sleeve 2-5; the foundation steel mesh is tied.

[0069] Continue releasing the steel strand bundle 1-3, causing the positioning plate 3-5 to continue sliding down until it contacts the V-groove 3-3;

[0070] Understandably, the steel strand bundle 1-3 cannot rotate during the above process because the pointed lock head 1-4 is restricted from rotating by the compression plate 3-18, and the positioning plate 3-5 cannot rotate due to the restriction of the protrusion and the groove.

[0071] When the V-protrusion 3-7 of the positioning plate 3-5 falls into the V-groove 3-3, the pin head of the spring pin 3-19 is pressed back into the spring pin hole 3-13, the spring 3-16 pushes the second rod 3-15 to make the pressing plate 3-18 move away from the pointed lock head 1-4, the pointed lock head 1-4 is released and falls directly through the lock hole 3-4.

[0072] Rotate the steel strand bundle 1-3 by 90° to rotate the pointed lock head 1-4 by 90°, then tighten the steel strand bundle 1-3; then pour concrete.

[0073] After the foundation 5 is properly cured, prestress is applied to one end of the steel strand bundle 1-3 located on the anchor ring pad 1-2 and the upper anchor ring 1-1. Once the design standard value is reached, an overall prestressed system is formed, and then the anchor is sealed.

[0074] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A prestressed tensile-shear multi-joint PHC pile connection structure, comprising multiple PHC pipe piles and a pile cap foundation, wherein the PHC pipe piles comprise prestressed steel bars and high-strength concrete, and the top and bottom ends of the PHC pipe piles are provided with pipe pile sleeves and pipe pile end plates; characterized in that, A fixing lock head connection device is pre-embedded at the base of the PHC pipe pile, and the bottom end is connected to the steel pile tip; the prestressed steel strand kit passes through the interior of multiple PHC pipe piles and is used in conjunction with the lock head connection device. The locking head connection device includes an anchor ring pre-embedded at the root of the PHC pipe pile at the bottom. Two symmetrical baffles are set at the bottom of the anchor ring, and a V-groove is opened in the middle of the anchor ring. A locking hole is opened at the bottom of the V-groove. The prestressed steel strand kit includes a bundle of steel strands, one end of which passes through the anchor ring pad and the upper anchor ring, and the other end is fixedly connected to a pointed lock head; a positioning plate is also provided, which can drive the pointed lock head through the lock hole.

2. The prestressed tensile-shear multi-joint PHC pile connection structure as described in claim 1, characterized in that, The upper PHC pipe pile is equipped with a hollow sleeve, and the bottom end of the hollow sleeve is fixedly connected to an annular sealing plate; the top of the hollow sleeve is provided with an anchor ring pad, the top of the anchor ring pad is flush with the top of the foundation, and an upper anchor ring is provided on the top of the anchor ring pad; reinforcing bars are fixedly connected to the outer wall of the top of the hollow sleeve and tied together with the steel mesh of the foundation.

3. The prestressed tensile-shear multi-joint PHC pile connection structure as described in claim 1, characterized in that, A ring-shaped connecting plate is welded to the top end plate of the PHC pipe pile. Multiple fixing blocks are arranged in a circular array on the upper part of the connecting plate. Mechanical connecting sleeves are fixedly installed inside the fixing blocks, and the mechanical connecting sleeves are connected to the anchoring steel bars.

4. The prestressed tensile-shear multi-joint PHC pile connection structure as described in claim 1, characterized in that, The pointed lock head includes a cylindrical cone with symmetrical auxiliary plates on the cylindrical cone, and the shape of the keyhole matches the shape of the pointed lock head.

5. The prestressed tensile-shear multi-joint PHC pile connection structure as described in claim 1, characterized in that, The positioning disk includes a cylindrical counterweight disk with a V-shaped protrusion fixedly connected to its bottom. The V-shaped protrusion can be placed into a V-groove. A wire harness through hole is provided in the center of the positioning disk, and a first groove is provided on both sides, which are vertically connected to the top surface of the positioning disk. The bottom of the first groove is connected to a horizontal second groove, which is not connected to the wire harness through hole. Above the second groove, the first groove is connected to a horizontal third groove, which is connected to the wire harness through hole. The bottom of the second groove is connected to a vertical fourth groove, and a spring pin hole is opened on the bottom side of the fourth groove near the wire harness through hole.

6. The prestressed tensile-shear multi-joint PHC pile connection structure as described in claim 5, characterized in that, The positioning plate is equipped with a linkage mechanism, which includes a first rod in the first groove, a second rod in the second groove, a third rod in the third groove, and a spring pin in the fourth groove. One end of the second rod is fixedly connected to the first rod, and the other end is connected to a spring, which abuts against the inner wall of the second groove away from the first groove. One end of the third rod is fixedly connected to the first rod, and the other end extends out of the third groove and connects to the extrusion plate. The spring pin is fixedly connected to the second rod with the pin head facing downward.

7. The prestressed tensile-shear multi-joint PHC pile connection structure as described in claim 1, characterized in that, The PHC pipe pile has corresponding grooves inside, and the side wall of the positioning plate has protrusions that can be inserted into the grooves. The outer diameter of the positioning plate matches the inner diameter of the PHC pipe pile.

8. A construction method for a prestressed tensile-shear multi-joint PHC pile connection structure as described in any one of claims 1-7, characterized in that, The specific steps include: All PHC pipe piles are driven into the formation. Then, the pointed lock head is placed in the positioning plate and clamped by the extrusion plate. The other end of the steel strand bundle passes through the hollow sleeve first, and then through the anchor ring pad and the upper anchor ring. Insert the protrusion of the positioning plate into the groove inside the PHC pipe pile, place the positioning plate inside the PHC pipe pile, and let it slide down a certain distance to reserve the position for installing the hollow sleeve. Hollow sleeves are installed inside the upper PHC pipe piles, and annular connecting plates are welded to the top pipe pile end plates and anchoring steel bars are installed; anchor ring pads and upper anchor rings are set at the top of the hollow sleeves; and the foundation steel mesh is tied. Continue releasing the steel strand bundle, causing the V-bump to fall into the V-groove, the spring pin head to be pressed back into the spring pin hole, the spring to push the second rod to move the extrusion plate away from the pointed lock head, and the pointed lock heads 1-4 to be released and fall through the lock hole; Rotate the steel strand bundle 90° to turn the pointed lock head, then tighten the steel strand bundle; then pour concrete. After the foundation is properly cured, prestress is applied to one end of the steel strand bundle located at the upper anchor ring. Once the design standard value is reached, an overall prestressed system is formed, and then the anchor is sealed.

9. The construction method of a prestressed tensile-shear multi-joint PHC pile connection structure as described in claim 8, characterized in that, When driving all PHC pipe piles into the stratum, first weld and fix the steel pile tip at the bottom end of the bottom PHC pipe pile, and then drive the bottom end of the bottom PHC pipe pile into the stratum; then align the bottom end plate of the PHC pipe pile to be driven with the top end plate of the PHC pipe pile driven into the stratum, and weld them together as one piece. After cleaning the weld and applying anti-corrosion material to the connection, continue driving the pile.

10. The construction method of a prestressed tensile-shear multi-joint PHC pile connection structure as described in claim 9, characterized in that, When the PHC pipe pile to be driven is aligned with the PHC pipe pile driven into the stratum, the grooves need to be aligned vertically.

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