Buckle type pipe pile connector and design method thereof

Abstract

The invention relates to a buckle type pipe pile connector and a design method thereof.The buckle type pipe pile connector comprises pipe piles, end plates, buckle connecting pieces, mounting grooves, cover plates and buckle grooves, the two sections of pipe piles are in butt joint through the end plates, a plurality of evenly-distributed openings are formed in the end plates in the circumferential direction, the cover plates are arranged on the plate faces, opposite to each other, of the two butt-joint end plates, and the buckle grooves are formed in the end plates. The cover plate seals the opening to form mounting grooves, two corresponding mounting grooves are in butt joint to form a mounting cavity, a buckle connecting piece matched with the mounting cavity is arranged in the mounting cavity, buckle grooves are formed in the two sides of the front end of the mounting cavity, and a deformation joint is formed in the center of the front end of the buckle connecting piece. The two sides of the front end of the buckle connecting piece are located at the deformation joint and protrude outwards to form buckles matched with the buckle grooves. The joint has the beneficial effects that vertical connection of a traditional mechanical joint is changed into horizontal connection, the joint is simple and reliable, the stress of the joint is changed into surface stress from point stress of vertical connection, the stress of the joint is uniform, and the bearing performance is higher.

Description

Technical Field

[0001] The present invention relates to the technical field, and in particular to a snap-on pipe pile joint and a design method thereof. Background Art

[0002] Prestressed high-strength concrete pipe piles are typically connected using welding and mechanical joints. Welding is the most commonly used method, but weld defects can affect the pile's bearing capacity, and uneven weld thickness can affect the verticality of the pile. Welded joints, in particular, can significantly delay pile driving, with the weld installation and cooling of each joint taking 30 to 60 minutes. Mechanical joints are now becoming increasingly common, with a variety of joint methods available. Commonly used mechanical joints generally utilize vertical socket-type driving, rack-type or nose-type vertical connections, and horizontal spring clamping. The most significant drawback of the commonly used socket-type mechanical joint is that, due to its socket-type structure and spring clamping, the joint experiences a certain amount of opening displacement when subjected to vertical pullout and horizontal bending moments, reducing its bearing capacity and impacting its durability. Furthermore, the structural complexity and higher cost of mechanical joints compared to welded joints also significantly hinder their widespread use. How to facilitate the manufacture of pipe piles and solve the problem of pile connection, make the pipe pile manufacturing process simple, make the pile sinking method highly adaptable, and ensure that the bearing capacity of the pipe pile joints is not lower than the strength of the pile body, is the key technical problem that needs to be solved in the current pipe pile connection. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a snap-on pipe pile joint and a design method thereof, which transforms the vertical connection of a traditional mechanical joint into a horizontal connection. The joint is simple and reliable, and the force on the joint is transformed from the point force of the vertical connection to the surface force. The joint is evenly stressed and has higher bearing performance.

[0004] The purpose of the present invention is achieved through the following technical solutions: The lockhole engages with the lockhole that engages with the lockhole on the lockhole, and the lockhole engages with the lockhole on the lockhole.

[0005] Furthermore, the cross section of the cover plate is trumpet-shaped, and the internal space of the cover plate and the opening form a mounting groove.

[0006] Furthermore, the snap connector gradually tapers from thick to thin from the rear end to the front end and forms a taper of 1° to 3° along the length direction.

[0007] Furthermore, the length of the deformation joint is more than 1.2 times the length of the buckle, and the width of the deformation joint is twice the width of the buckle + the installation gap.

[0008] Furthermore, based on the above-mentioned snap-on pipe pile joint, the present invention also provides a design method of the snap-on pipe pile joint, comprising: Process anchor holes and tension bolt holes on the end plates, and cut openings and grooves on the end plates; The cover plate is made by cutting and bending the steel plate, and the cover plate is welded at the opening on the end plate to form the installation groove; Tie up the pipe pile reinforcement cage and embed prestressed steel rods in the pipe pile reinforcement cage, install end plates at the ends of the pipe pile reinforcement cage, anchor the swaged heads of the prestressed steel rods in the anchor holes on the end plates, install tension bolts in the tension bolt holes and apply prestress to the prestressed steel rods through the tension bolts, then install steel formwork and pour pipe pile concrete to complete pipe pile prefabrication; Connect the two pipe piles through the end plates so that the installation grooves on the two end plates connect to form an installation cavity, and the grooves on the two end plates connect to form a buckle groove; Insert the snap connector into the installation cavity until the buckle on the snap connector is completely embedded in the buckle groove; Design and verify the cross-section and bearing capacity of snap-on connectors.

[0009] Furthermore, a deformation seam is provided at the front end of the snap connector. When the snap connector is driven into the installation cavity, the deformation seam shrinks. After the buckle on the snap connector is fully embedded in the buckle groove, the deformation seam recovers and the snap connector is automatically locked.

[0010] Furthermore, a plurality of tensioning bolt holes are provided, and the plurality of tensioning bolt holes are evenly distributed along the circumferential direction of the end plate.

[0011] Furthermore, the design and verification of the cross-section and bearing capacity of the snap connector includes: Design value of tensile load of snap connector under pull-out load of pipe pile foundation , where N is the design value of the pull-out load of the pile foundation, in kN; is the side wall friction resistance of the pile, unit is kN / m 2 ; is the length of the pile section, in m; is the radius of the pile, in m; The number of snap connectors at the pipe-pile joint; Design value of shear load of snap connector under horizontal load of pipe pile foundation , where is the design value of horizontal load of pipe pile foundation, unit is kN; is the top surface earth pressure of the i-th soil layer on the active side of the pipe pile , unit kN / m 2 ; is the bottom earth pressure of the i-th layer of soil on the active side of the pipe pile , unit kN / m 2 ; is the thickness of the i-th soil layer, in m; n is the number of soil layers that the horizontal load passes through to the pipe pile joint; Under the action of bending moment load, the stress at the pipe pile joint is linearly distributed, so there is a relationship , then the tensile load design value of the snap connector with the largest tensile force is , where is the design value of the bending moment load of the pipe pile joint, in kN▪m; The first side of the neutral axis of the pile Design value of tensile load for each snap-on connector , unit kN; The first side of the neutral axis of the pile The distance between the snap connector and the neutral axis of the pile, in meters; The distance between the snap connector farthest from the neutral axis of the pile and the neutral axis of the pile, in meters; Abdominal tensile stress of snap-fit ​​connectors , , where is the belly width of the snap connector, in m; is the length of the expansion joint, in m; is the length of the snap connector, in meters; The tensile yield strength of the material of the snap connector, in kN / m 2 ; Belly shear stress of snap-fit ​​connectors , , where is the shear yield strength of the material of the snap connector, kN / m 2 ; Shear stress on both wings of the snap-fit ​​connector , , where The height of the two wings of the snap connector, in meters.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. When connecting the pipe piles, the present invention only requires aligning the installation grooves on the upper and lower end plates to form a closed installation cavity. Compared with the traditional mechanical vertical connection, the connection difficulty is less.

[0013] 2. The pipe pile joint of the present invention drives the snap connector into the installation cavity from the outer peripheral surface of the end plate along the radial direction of the end plate toward the center of the end plate. A deformation seam is provided at the front end of the snap connector. The deformation seam shrinks during the driving process. After the snap on the snap connector is fully embedded in the snap groove, the deformation seam is restored and the snap connector is automatically locked. It is easier than the vertical socket pipe pile joint, saves time, and has a faster docking speed.

[0014] 3. The present invention changes the line connection of the welding joint and the point connection of the traditional mechanical connection into a surface connection of the snap connector, so that the joint is more evenly stressed and has a higher bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic cross-sectional view of the pipe pile along the buckle groove in the present invention; Figure 2 Schematic cross-sectional view of the pipe pile along the deformation joint in the present invention; Figure 3 Schematic diagram of the planar structure of the end plate of the present invention; Figure 4 Schematic diagram of the overall structure of the pipe pile joint in the present invention; Figure 5 for Figure 3 AA cross-sectional diagram in; Figure 6 for Figure 3 BB cross-section diagram in; Figure 7 Schematic diagram of the three-dimensional structure of the snap connector in the present invention; Figure 8 Schematic diagram of the three-dimensional structure of the buckle slot in the present invention; Figure 9 Schematic diagram of the installation of the snap connector in the present invention; Figure 10 Schematic diagram of pull-out analysis of the pipe pile joint in the present invention; Figure 11 Schematic diagram of shear stress analysis of the pipe pile joint in the present invention; Figure 12 Schematic diagram of bending stress analysis of the pipe pile joint in the present invention; Figure 13 Schematic diagram of the tensile stress analysis of the belly of the snap connector in the present invention; Figure 14 Schematic diagram of shear stress analysis of the two wings of the snap connector in the present invention.

[0016] In the figure: 1. Pipe pile; 101. End plate; 2. Anchor hole; 201. Prestressed steel rod; 202. Head; 3. Snap connector; 301. Snap; 302. Expansion joint; 4. Mounting groove; 401. Cover plate; 402. Snap groove; 403. Weld; 5. Tension bolt hole. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0018] like Figures 1-9 As shown, a snap-on pipe pile joint comprises a pipe pile 1, an end plate 101, a snap-on connector 3, a mounting groove 4, a cover plate 401, and a snap-on groove 402. The end plate 101 is fixed to the end of the pipe pile 1. When connecting the piles, two sections of the pipe pile 1 are butted together via the end plates 101. Both end plates 101 are provided with mounting grooves 4 having a trumpet-shaped cross-section. When butt-jointed, the mounting grooves 4 on the two end plates 101 abut to form a closed mounting cavity. By driving a snap-on connector 3 adapted for the mounting cavity into the cavity and automatically locking the snap-on connector 3 within the cavity, a fixed connection is achieved between the two end plates 101, thereby completing the pile connection.

[0019] like Figure 3 、 Figure 4 、 Figure 6 、 Figure 8 、 Figure 9 As shown, a plurality of evenly distributed openings are provided on the end plate 101 along the circumferential direction of the end plate 101. The openings extend from the outer peripheral surface of the end plate 101 along the radial direction of the end plate 101 toward the center of the end plate 101. The openings on the two butted end plates 101 correspond to each other. Cover plates 401 are provided on the opposite surfaces of the two butted end plates 101 at the openings. The cover plates 401 are welded to the end plates 101 and form welds 403, so that the cover plates 401 close the openings to form a mounting groove 4 with a trumpet-shaped cross section. The corresponding two mounting grooves 4 are butted together to form a mounting cavity that is closed on all sides. Figure 8 As shown, the cross section of the cover plate 401 is trumpet-shaped, and the internal space of the cover plate 401 and the opening form the mounting groove 4 .

[0020] like Figure 1 、 Figure 2 、 Figure 5 、 Figure 7 、 Figure 8As shown, snap grooves 402 are provided on both sides of the front end of the installation cavity, and a deformation gap 302 is provided at the center of the front end of the snap connector 3 along the length direction of the snap connector 3. Both sides of the front end of the snap connector 3 are located at the deformation gap 302 and protrude outward to form snaps 301 that adapt to the snap grooves 402. The snap grooves 402 are formed by two grooves connected together, and the two grooves are respectively provided on the two connected end plates 101. When the snap connector 3 is driven into the installation cavity, the front end of the snap connector 3 is inserted into the installation cavity. The snap connector is squeezed, causing the deformation gap 302 to narrow. When the snap 301 on the snap connector 3 reaches the snap groove 402 position, the deformation gap 302 elastically recovers, allowing the snap 301 to be completely embedded in the snap groove 402, thereby automatically locking the snap connector 3 in the installation cavity.

[0021] like Figure 7 As shown, in order to facilitate the insertion of the snap connector 3 into the installation cavity, the rear end of the snap connector 3 gradually becomes thinner from thick to the front end and forms a taper of 1° to 3° along the length direction. The installation error between the snap connector 3 and the installation cavity is less than 0.5mm; accordingly, the snap connector 3 is adapted to the installation cavity, so the cover plate 401 and the installation cavity also have a taper of 1° to 3° in the length direction.

[0022] like Figure 7 、 Figure 9 As shown, in this embodiment, the upper and lower surfaces of the snap connector 3 are horizontal, and the cross-section of the snap connector 3 is symmetrical trumpet-shaped, wherein the angle θ between the upper and lower inclined surfaces and the horizontal plane is 45° to 60°, the length l3 of the deformation gap 302 is more than 1.2 times the length of the snap 301, and the width l5 of the deformation gap 302 is twice the width of the snap 301 + an installation gap of 1.0 mm to 2.0 mm.

[0023] A design method for the above-mentioned snap-on pipe pile joint includes the following steps: (1) Process the end plate 101. Specifically, process the anchor holes 2 and the tension bolt holes 5 on the end plate 101, and cut openings and grooves on the end plate 101. Figure 3 As shown, there are multiple tensioning bolt holes 5 , and the multiple tensioning bolt holes 5 are evenly distributed along the circumferential direction of the end plate 101 .

[0024] (2) Process and install the cover plate 401. Specifically, the cover plate 401 is made by cutting and bending a steel plate, and the cover plate 401 is welded to the opening on the end plate 101 to form the installation groove 4; accordingly, in order to adapt to the snap connector 3, the bottom edge angle of the cover plate 401 is also 45° to 60°.

[0025] (3) Prefabricate pipe pile 1. Specifically, tie the pipe pile reinforcement cage on the table formwork and embed the prestressed steel rod 201 in the pipe pile reinforcement cage. Install the end plate 101 at the end of the pipe pile reinforcement cage. Anchor the swaged head 202 of the prestressed steel rod 201 in the anchor hole 2 on the end plate 101. Install the tensioning bolt in the tensioning bolt hole 5. Connect the external loading device through the tensioning bolt to apply prestress to the prestressed steel rod 201. Then install the steel formwork and pour the concrete of the pipe pile 1. After centrifugal forming, steam curing and tensioning, the prefabrication of the pipe pile 1 is completed and the finished pipe pile 1 is inspected.

[0026] (4) Connect the piles. Specifically, connect the two sections of pipe piles 1 through the end plates 101 so that the installation grooves 4 on the two end plates 101 are connected to form an installation cavity, and the grooves on the two end plates 101 are connected to form a buckle groove 402.

[0027] (5) Installation of the pipe pile 1 joint. Specifically, the snap connector 3 is driven into the installation cavity until the snap 301 on the snap connector 3 is completely embedded in the snap groove 402, so that the snap connector 3 is automatically locked in the installation cavity, thereby fixing the two end plates 101 and completing the docking of the two pipe piles 1.

[0028] (6) Design and verify the cross section and bearing capacity of the snap connector 3, including the following design and verification contents: like Figure 10 As shown in the figure, under the action of pull-out load, the design value of the tensile load of the snap connector 3 is , where N is the design value of the pull-out load of the pile foundation, in kN; is the side wall friction resistance of the pile, unit is kN / m 2 ; is the length of the pile section, in m; is the radius of the pile, in m; It is the number of snap connectors at the pipe-pile joint.

[0029] like Figure 11 As shown, under the horizontal load of the pile foundation, the shear load design value of the snap connector 3 is , where is the design value of horizontal load of pipe pile foundation, unit is kN; is the top surface earth pressure of the i-th soil layer on the active side of the pipe pile , unit kN / m 2 ; is the bottom earth pressure of the i-th layer of soil on the active side of the pipe pile , unit kN / m 2 ; is the thickness of the i-th soil layer, in m; n is the number of soil layers that the horizontal load passes through to the pipe pile joint.

[0030] like Figure 12 As shown, under the action of bending moment load, due to the linear distribution of stress at the pipe pile joint, there is a relationship , then the tensile load design value of the snap connector 3 with the largest tensile force is , where is the design value of the bending moment load of the pipe pile joint, in kN▪m; The first side of the neutral axis of the pile Design value of tensile load of snap connector 3 , unit kN; The first side of the neutral axis of the pile The distance between the snap connector 3 and the neutral axis of the pile, in meters; The distance between the snap connector 3 farthest from the neutral axis of the pile and the neutral axis of the pile, in meters. The neutral axis of the pile is the axis where the normal stress of the pile cross section is zero. The two sides of the neutral axis of the pile are tensile stress and compressive stress respectively.

[0031] like Figure 7 、 Figure 13 As shown, the tensile stress of the belly of the snap connector 3 is , , where is the belly width of the snap connector 3, in m; is the length of the deformation joint 302, in m; is the length of the snap connector 3, in m; is the tensile yield strength of the material of the snap connector 3, in kN / m 2 ; Abdominal shear stress of snap connector 3 , , where is the shear yield strength of the material of the snap connector 3, kN / m 2 ; like Figure 7 、 Figure 14 As shown, the tension of the snap connector 3 Shear stress at the shear interface of the two wings Balance, so the shear stress on both wings , , where is the height of the two wings of the snap connector 3, in m.

[0032] Based on the above-mentioned snap-on pipe pile joint and its corresponding design method, when performing pile connection operations at the construction site, first clean the debris in the installation groove 4 on the end plate 101 before sinking the piles. When sinking the piles, pipe piles 1 with a diameter of 600 mm or less can be sunk by hammering or static pressure, and pipe piles 1 with a diameter of more than 600 mm can be sunk by planting piles. When connecting the piles, first drive in the lower section of the pipe pile 1. When the top surface of the lower section of the pipe pile 1 is about 1.0 m above the ground, hoist the upper section of the pipe pile 1. When the axes of the upper and lower sections of the pipe pile 1 completely coincide with each other on a vertical line and the upper and lower installation grooves 4 are aligned to form an installation cavity, use a hammer to drive the snap connector 3 into each installation cavity until the snap 301 on the snap connector 3 is completely embedded in the snap groove 402, so that the snap connector 3 is automatically locked in the installation cavity, thereby completing the pile connection construction. During the pile connection process, it is only necessary to align the installation grooves 4 on the upper and lower end plates 101 to form a closed installation cavity, and then drive the snap connector 3 into the installation cavity from the outer peripheral surface of the end plate 101 along the radial direction of the end plate 101 toward the center of the end plate 101. Compared with the traditional mechanical vertical connection, the docking difficulty is small and the docking speed is faster; the entire joint is simple to manufacture, and the line connection of the welded joint and the point connection of the traditional mechanical connection are changed to a 3-surface connection of the snap connector, so that the joint is evenly stressed and has a higher bearing capacity.

[0033] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A snap-on pipe pile joint, characterized in that: The invention comprises a pipe pile (1), an end plate (101), a snap connector (3), an installation groove (4), a cover plate (401) and a snap groove (402), wherein the end of the pipe pile (1) is provided with an end plate (101), two sections of the pipe pile (1) are butt-jointed via the end plate (101), a plurality of evenly distributed openings are provided on the end plate (101) along the circumferential direction of the end plate (101), the openings extend from the outer peripheral surface of the end plate (101) along the radial direction of the end plate (101) toward the center of the end plate (101), the openings on the two butted end plates (101) correspond to each other, and the cover plates (401) are provided on the opposite plate surfaces of the two butted end plates (101) at the openings, and the cover plates ( 401) closes the opening to form a mounting groove (4) with a trumpet-shaped cross section, and the corresponding two mounting grooves (4) are butted together to form a mounting cavity that is closed on all sides. A snap connector (3) adapted to the mounting cavity is provided in the mounting cavity, and snap connector grooves (402) are provided on both sides of the front end of the mounting cavity. A deformation seam (302) is provided at the center of the front end of the snap connector (3) along the length direction of the snap connector (3). Both sides of the front end of the snap connector (3) are located at the deformation seam (302) and protrude outward to form snaps (301) adapted to the snap connector groove (402). The snap connector groove (402) is formed by butting together two grooves, and the two grooves are respectively provided on the two butted end plates (101).

2. The snap-on pipe pile joint according to claim 1, characterized in that: The cross section of the cover plate (401) is trumpet-shaped, and the internal space of the cover plate (401) and the opening form a mounting groove (4).

3. The snap-on pipe pile joint according to claim 1, characterized in that: The snap connector (3) gradually tapers from thick to thin from the rear end to the front end and forms a taper of 1° to 3° along the length direction.

4. The snap-on pipe pile joint according to claim 1, characterized in that: The length of the deformation joint (302) is more than 1.2 times the length of the buckle (301), and the width of the deformation joint (302) is twice the width of the buckle (301) + the installation gap.

5. A design method for a snap-on pipe pile joint, characterized in that: include: Anchor holes (2) and tension bolt holes (5) are machined on the end plate (101), and openings and grooves are cut on the end plate (101); A cover plate (401) is formed by cutting and bending a steel plate, and the cover plate (401) is welded to the opening on the end plate (101) to form a mounting groove (4); Binding the pipe pile reinforcement cage and pre-embedding the prestressed steel rod (201) in the pipe pile reinforcement cage, installing the end plate (101) at the end of the pipe pile reinforcement cage, anchoring the swaged head of the prestressed steel rod (201) in the anchor hole (2) on the end plate (101), installing the tensioning bolt hole (5) and applying prestress to the prestressed steel rod (201) through the tensioning bolt, and then installing the steel formwork to cast the pipe pile (1) concrete, thereby completing the prefabrication of the pipe pile (1); The two pipe piles (1) are butted together through the end plates (101), so that the mounting grooves (4) on the two end plates (101) are butted together to form a mounting cavity, and the grooves on the two end plates (101) are butted together to form a buckle groove (402); Insert the snap connector (3) into the installation cavity until the snap (301) on the snap connector (3) is completely embedded in the snap groove (402); The cross section and bearing capacity of the snap connector (3) are designed and verified.

6. The design method of the snap-on pipe pile joint according to claim 5, characterized in that: A deformation seam (302) is provided at the front end of the snap connector (3). When the snap connector (3) is driven into the installation cavity, the deformation seam (302) contracts. After the snap connector (301) on the snap connector (3) is completely embedded in the snap groove (402), the deformation seam (302) is restored and the snap connector (3) is automatically locked.

7. The design method of the snap-on pipe pile joint according to claim 5, characterized in that: The design and verification of the cross section and bearing capacity of the snap connector (3) includes: Design value of tensile load of snap connector under pull-out load of pipe pile foundation , where N is the design value of the pull-out load of the pile foundation, in kN; is the side wall friction resistance of the pile, unit is kN / m 2 ; is the length of the pile section, in m; is the radius of the pile, in m; The number of snap connectors at the pipe-pile joint; Design value of shear load of snap connector (3) under horizontal load of pipe pile foundation , where is the design value of horizontal load of pipe pile foundation, unit is kN; is the top surface earth pressure of the i-th soil layer on the active side of the pipe pile , unit kN / m 2 ; is the bottom earth pressure of the i-th layer of soil on the active side of the pipe pile , unit kN / m 2 ; is the thickness of the i-th soil layer, in m; n is the number of soil layers that the horizontal load passes through to the pipe pile joint; Under the action of bending moment load, the stress at the pipe pile joint is linearly distributed, so there is a relationship , then the tensile load design value of the snap connector (3) with the largest tensile force is , where is the design value of the bending moment load of the pipe pile joint, in kN▪m; The first side of the neutral axis of the pile Design value of tensile load of snap-on connector (3) , unit kN; The first side of the neutral axis of the pile The distance between the snap connector (3) and the neutral axis of the pile, in m; The distance between the snap connector (3) farthest from the neutral axis of the pile and the neutral axis of the pile, in meters; Tensile stress in the belly of the snap connector (3) , , where is the belly width of the snap connector (3), in m; is the length of the expansion joint (302), in m; is the length of the snap connector (3), in m; is the tensile yield strength of the material of the snap connector (3), in kN / m 2 ; Abdominal shear stress of the snap connector (3) , , where is the shear yield strength of the material of the snap connector (3), kN / m 2 ; Shear stress on both wings of the snap connector (3) , , where is the height of the two wings of the snap connector (3), in m.

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