A snap-on pipe pile joint and a design method thereof

Abstract

The application relates to a buckle type pipe pile joint and a design method thereof, the buckle type pipe pile joint comprising a pipe pile, an end plate, a buckle connecting piece, a mounting groove, a cover plate and a buckle groove, two sections of pipe piles are butted through the end plate, a plurality of uniformly distributed openings are arranged on the end plate in the circumferential direction, the cover plates are arranged on the opposite plate surfaces of the two butted end plates, the cover plates close the openings to form the mounting grooves, the two corresponding mounting grooves are butted to form a mounting cavity, the buckle connecting piece matched with the mounting cavity is arranged in the mounting cavity, buckle grooves are arranged on the two sides of the front end of the mounting cavity, a deformation joint is arranged at the center of the front end of the buckle connecting piece, and the two sides of the front end of the buckle connecting piece are outwardly protruded at the deformation joint to form buckles matched with the buckle grooves. The application has the beneficial effects that the vertical connection of the traditional mechanical joint is changed into horizontal connection, the joint is simple and reliable, the stress of the joint is changed from point stress of the vertical connection into surface stress, the stress of the joint is uniform, and the bearing capacity is higher.

Description

Technical Field

[0001] This invention relates to the technical field, specifically to a snap-fit ​​pipe pile joint and its design method. Background Technology

[0002] Prestressed high-strength concrete pipe pile splicing methods typically employ welding and mechanical joints. Welding is the most common method, but weld defects can affect the pile's bearing capacity, and uneven weld thickness can impact the pile's verticality. In particular, welded joints significantly delay pile driving time, with each joint requiring 30-60 minutes for weld application and cooling. Mechanical joints are increasingly being adopted, offering diverse methods. Commonly used mechanical joints are designed with vertical socket-type driving, employing rack-and-pinion or convex-head vertical connections, and horizontal spring clamping. The biggest drawback of commonly used socket-type mechanical joints is that, due to the socket method and spring clamping, the joint experiences a certain amount of opening displacement under vertical pull-out forces and horizontal bending moments, reducing its bearing capacity and affecting its durability. Furthermore, the complex structure and higher cost of mechanical joints compared to welded joints are also significant factors hindering their widespread adoption. The key technical problem that needs to be solved in pipe pile splicing is how to facilitate pipe pile manufacturing, solve the problem of pile splicing, ensure that the pipe pile manufacturing process is simple, the pile driving method is highly adaptable, and the bearing capacity of the pipe pile joint is not lower than the strength of the pile body. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a snap-fit ​​pipe pile joint and its design method, which changes the vertical connection of the traditional mechanical joint to a horizontal connection. The joint is simple and reliable, and the stress on the joint changes from point stress in vertical connection to surface stress, resulting in uniform stress distribution and higher load-bearing capacity.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A snap-fit ​​pipe pile connector includes a pipe pile, an end plate, a snap-fit ​​connector, an installation groove, a cover plate, and a snap-fit ​​slot. The pipe pile has an end plate at its end, and two pipe pile sections are joined together via the end plate. Multiple evenly distributed openings are formed on the end plate along its circumferential direction, extending radially from the outer circumference of the end plate towards its center. The openings on the two joined end plates correspond one-to-one. Cover plates are provided at the openings on opposite surfaces of the two joined end plates, closing the openings to form a funnel-shaped installation groove. Two corresponding installation grooves are joined to form a closed installation cavity. A snap-fit ​​connector adapted to the installation cavity is provided within the cavity. Snap-fit ​​slots are provided on both sides of the front end of the installation cavity. An expansion joint is formed at the center of the front end of the snap-fit ​​connector along its length. Both sides of the front end of the snap-fit ​​connector protrude outwards at the expansion joint to form a snap that adapts to the snap-fit ​​slot. The snap-fit ​​slot is formed by the joining of two grooves, which are respectively located on the two joined end plates.

[0006] Furthermore, the cover plate has a trumpet-shaped cross-section, and the internal space of the cover plate and the opening form an installation groove.

[0007] Furthermore, the rear end of the snap-fit ​​connector gradually tapers from the front end to the rear end, forming a taper of 1° to 3° along its length.

[0008] Furthermore, the length of the expansion joint is more than 1.2 times the length of the clip, and the width of the expansion joint is twice the width of the clip plus the installation gap.

[0009] Furthermore, based on the above-mentioned snap-fit ​​pipe pile joint, the present invention also provides a design method for a snap-fit ​​pipe pile joint, comprising:

[0010] Anchor holes and tension bolt holes are machined on the end plate, and openings and grooves are cut on the end plate;

[0011] The cover plate is made by cutting and bending steel plates, and the cover plate is welded to the opening on the end plate to form an installation groove;

[0012] The pipe pile reinforcement cage is tied and prestressed steel bars are pre-embedded in the pipe pile reinforcement cage. End plates are installed at the ends of the pipe pile reinforcement cage. The upset heads of the prestressed steel bars are anchored in the anchor holes on the end plates. Tensioning bolts are installed at the tensioning bolt holes and prestress is applied to the prestressed steel bars through the tensioning bolts. Then, steel formwork is installed and the pipe pile concrete is poured to complete the pipe pile prefabrication.

[0013] Two pipe piles are joined together through end plates, so that the mounting grooves on the two end plates are joined together to form an mounting cavity, and the grooves on the two end plates are joined together to form a snap-fit ​​groove.

[0014] Drive the snap-fit ​​connector into the mounting cavity until the snap-fit ​​connector is fully embedded in the snap-fit ​​groove;

[0015] The cross-section and load-bearing capacity of the snap-fit ​​connectors were designed and verified.

[0016] Furthermore, the front end of the snap-fit ​​connector is provided with an expansion joint. During the process of driving the snap-fit ​​connector into the installation cavity, the expansion joint contracts. After the snap on the snap-fit ​​connector is fully embedded in the snap slot, the expansion joint recovers and the snap-fit ​​connector automatically locks.

[0017] Furthermore, multiple tension bolt holes are provided, and these multiple tension bolt holes are evenly distributed along the circumferential direction of the end plate.

[0018] Furthermore, when performing design verification of the cross-section and load-bearing capacity of the snap-fit ​​connector, the following should be included:

[0019] The design value of the tensile load of the snap-fit ​​connector under the action of pull-out load in the pipe pile foundation. In the formula, N is the design value of the pull-out load of the pipe pile foundation, in kN; The side wall friction of the pipe pile, in kN / m 2 ; The length of the pipe pile section is in meters (m). The radius of the pipe pile is in meters. This refers to the number of snap-fit ​​connectors at the joint of the pipe pile;

[0020] The design value of the shear load on the snap-fit ​​connector of the pipe pile foundation under horizontal load. In the formula This represents the design value of the horizontal load for the pipe pile foundation, in kN. Earth pressure on the top surface of the i-th layer of soil on the active side of the pipe pile Unit: kN / m 2 ; Earth pressure at the bottom of the i-th layer of soil on the active side of the pipe pile Unit: kN / m 2 ; The thickness of the i-th soil layer is in meters; n is the number of soil layers through which the horizontal load passes to the pipe pile joint.

[0021] Under bending moment load, the pipe pile foundation exhibits a relationship due to the linear stress distribution at the pipe pile joints. The design value of the tensile load of the snap-fit ​​connector with the greatest tensile force is... In the formula The design value of the bending moment load of the pipe pile joint is given in kN·m. The first one on one side of the neutral axis of the pipe pile Design value of tensile load for each snap-fit ​​connector Unit: kN; The first one on one side of the neutral axis of the pipe pile The distance between each snap-fit ​​connector and the neutral axis of the pipe pile, in meters; The distance between the snap-fit ​​connector furthest from the neutral axis of the pipe pile and the neutral axis of the pipe pile, in meters;

[0022] Tensile stress on the web of the snap-fit ​​connector , In the formula The width of the snap-fit ​​connector is in meters (m). The length of the expansion joint is in meters (m). The length of the snap-fit ​​connector is in meters (m). The tensile yield strength of the material for the snap-fit ​​connector, in kN / m. 2 ;

[0023] Shear stress on the web of the snap-fit ​​connector , In the formula The shear yield strength of the material for the snap-fit ​​connector is given in kN / m.2 ;

[0024] Shear stress on both wings of the snap-fit ​​connector , In the formula The height of the two wings of the snap-fit ​​connector is in meters (m).

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. When connecting pipe piles, this invention only requires aligning the mounting grooves on the upper and lower end plates to form a closed mounting cavity, which is less difficult than the traditional mechanical vertical connection.

[0027] 2. The pipe pile joint of the present invention adopts the method of driving the snap-fit ​​connector into the installation cavity from the outer peripheral surface of the end plate along the radial direction of the end plate towards the center of the end plate. The front end of the snap-fit ​​connector is provided with an expansion joint. During the driving process, the expansion joint shrinks. After the snap on the snap-fit ​​connector is fully embedded in the snap-fit ​​groove, the expansion joint recovers and the snap-fit ​​connector automatically locks. It is easier, saves time and has a fast docking speed than the vertical socket method pipe pile joint.

[0028] 3. This invention changes the line connection of the welded joint and the point connection of the traditional mechanical connection to the surface connection of the snap-fit ​​connector, so that the joint is more evenly stressed and has a higher load-bearing capacity. Attached Figure Description

[0029] Figure 1 This is a cross-sectional schematic diagram of the pipe pile along the snap-fit ​​groove in this invention;

[0030] Figure 2 This is a schematic cross-sectional view of the pipe pile along the deformation joint in this invention;

[0031] Figure 3 This is a schematic diagram of the planar structure of the end plate in this invention;

[0032] Figure 4 This is a schematic diagram of the overall structure of the pipe pile joint in this invention;

[0033] Figure 5 for Figure 3 Schematic diagram of AA section in the middle;

[0034] Figure 6 for Figure 3 Schematic diagram of the BB cross section in the middle;

[0035] Figure 7 This is a three-dimensional structural diagram of the snap-fit ​​connector in this invention;

[0036] Figure 8 This is a three-dimensional structural diagram of the snap-fit ​​groove in this invention;

[0037] Figure 9This is a schematic diagram of the installation of the snap-fit ​​connector in this invention;

[0038] Figure 10 This is a schematic diagram of the pull-out stress analysis of the pipe pile joint in this invention;

[0039] Figure 11 This is a schematic diagram of the shear stress analysis of the pipe pile joint in this invention;

[0040] Figure 12 This is a schematic diagram of the bending stress analysis of the pipe pile joint in this invention;

[0041] Figure 13 This is a schematic diagram of the tensile stress analysis of the abdominal part of the snap-fit ​​connector in this invention;

[0042] Figure 14 This is a schematic diagram of the shear stress analysis of the two wings of the snap-fit ​​connector in this invention.

[0043] In the diagram: 1. Pipe pile; 101. End plate; 2. Anchor hole; 201. Prestressed steel bar; 202. Upsetting head; 3. Clip connector; 301. Clip; 302. Expansion joint; 4. Installation groove; 401. Cover plate; 402. Clip groove; 403. Weld; 5. Tensioning bolt hole. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0045] like Figures 1-9 As shown, a snap-fit ​​pipe pile connector includes a pipe pile 1, an end plate 101, a snap-fit ​​connector 3, an installation groove 4, a cover plate 401, and a snap-fit ​​groove 402. The end plate 101 is fixed to the end of the pipe pile 1. During splicing, two sections of pipe pile 1 are joined together via the end plate 101. Each of the two end plates 101 has a funnel-shaped installation groove 4. During splicing, the installation grooves 4 on the two end plates 101 are joined to form a closed installation cavity. By inserting a snap-fit ​​connector 3 into the installation cavity and automatically locking it within the cavity, a fixed connection between the two end plates 101 is achieved, thus completing the splicing.

[0046] like Figure 3 , Figure 4 , Figure 6 , Figure 8 , Figure 9As shown, multiple evenly distributed openings are formed on the end plate 101 along its circumferential direction. These openings extend radially from the outer circumference of the end plate 101 towards its center. The openings on two mating end plates 101 correspond one-to-one. Cover plates 401 are provided at the openings on the opposite surfaces of the two mating end plates 101. The cover plates 401 are welded to the end plates 101, forming a weld 403, thus closing the openings to form a funnel-shaped mounting groove 4. Two corresponding mounting grooves 4 are mated to form a closed mounting cavity. 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.

[0047] like Figure 1 , Figure 2 , Figure 5 , Figure 7 , Figure 8 As shown, snap-fit ​​grooves 402 are provided on both sides of the front end of the mounting cavity. An expansion joint 302 is formed at the center of the front end of the snap-fit ​​connector 3 along the length direction of the snap-fit ​​connector 3. The two sides of the front end of the snap-fit ​​connector 3 protrude outward at the expansion joint 302 to form snaps 301 that are adapted to the snap-fit ​​grooves 402. The snap-fit ​​groove 402 is formed by two grooves mating together, and the two grooves are respectively provided on the two mating end plates 101. When the snap-fit ​​connector 3 is driven into the mounting cavity, the front end of the snap-fit ​​connector 3 is inserted into the mounting cavity. The snap-fit ​​connector is squeezed, which narrows the expansion joint 302. When the snaps 301 on the snap-fit ​​connector 3 reach the position of the snap-fit ​​groove 402, the expansion joint 302 elastically recovers, so that the snaps 301 are completely embedded in the snap-fit ​​groove 402, thereby automatically locking the snap-fit ​​connector 3 in the mounting cavity.

[0048] like Figure 7 As shown, in order to facilitate the insertion of the snap-fit ​​connector 3 into the mounting cavity, the snap-fit ​​connector 3 gradually tapers from the rear end to the front end and forms a taper of 1° to 3° along the length direction. The installation error between the snap-fit ​​connector 3 and the mounting cavity is less than 0.5mm. Correspondingly, the snap-fit ​​connector 3 is adapted to the mounting cavity, so the cover plate 401 and the mounting cavity also have a taper of 1° to 3° in the length direction.

[0049] like Figure 7 , Figure 9 As shown, in this embodiment, the upper and lower surfaces of the snap fastener 3 are horizontal, and the cross-section of the snap fastener 3 is symmetrically flared. The angle θ between the upper and lower inclined surfaces and the horizontal surface is 45° to 60°. The length l3 of the expansion joint 302 is more than 1.2 times the length of the snap fastener 301, and the width l5 of the expansion joint 302 is twice the width of the snap fastener 301 plus 1.0 mm to 2.0 mm of installation gap.

[0050] A design method for the above-mentioned snap-fit ​​pipe pile joint includes the following steps:

[0051] (1) Machining the end plate 101. Specifically, anchor holes 2 and tension bolt holes 5 are machined on the end plate 101, and openings and grooves are cut into the end plate 101. Figure 3 As shown, there are multiple tension bolt holes 5, which are evenly distributed along the circumferential direction of the end plate 101.

[0052] (2) Process and install cover plate 401. Specifically, steel plate is cut and bent to make cover plate 401, and cover plate 401 is welded to the opening on end plate 101 to form installation groove 4; correspondingly, in order to adapt to the snap fastener 3, the bottom edge included angle of cover plate 401 is also 45°~60°.

[0053] (3) Precast Pipe Pile 1. Specifically, the pipe pile reinforcement cage is tied on the formwork and prestressed steel bars 201 are pre-embedded in the reinforcement cage of pipe pile 1. The end plate 101 is installed at the end of the pipe pile reinforcement cage. The upset head 202 of the prestressed steel bar 201 is anchored in the anchor hole 2 on the end plate 101. The tension bolt is installed at the tension bolt hole 5. The prestressed steel bar 201 is applied to the tension bolt by connecting the external loading device through the tension bolt. Then the steel formwork is installed and the concrete of pipe pile 1 is poured. After centrifugal molding, steam curing and release, the precast pipe pile 1 is completed and the finished pipe pile 1 is inspected.

[0054] (4) Splicing the piles. Specifically, the two sections of pipe pile 1 are joined together through the end plates 101, so that the mounting grooves 4 on the two end plates 101 are joined together to form a mounting cavity, and the grooves on the two end plates 101 are joined together to form a snap-fit ​​groove 402.

[0055] (5) Installation of the pipe pile 1 joint. Specifically, drive the snap fastener 3 into the installation cavity until the snap fastener 301 on the snap fastener 3 is fully embedded in the snap fastener groove 402, so that the snap fastener 3 automatically locks in the installation cavity, thereby fixing the two end plates 101 together and completing the docking of the two pipe piles 1.

[0056] (6) Perform design verification on the cross-section and bearing capacity of the snap-fit ​​connector 3, specifically including the following design verification contents:

[0057] like Figure 10 As shown, the design value of the tensile load of the snap-fit ​​connector 3 under the action of pull-out load in the pipe pile foundation is... In the formula, N is the design value of the pull-out load of the pipe pile foundation, in kN; The side wall friction of the pipe pile, in kN / m 2 ; The length of the pipe pile section is in meters (m). The radius of the pipe pile is in meters. This refers to the number of snap-fit ​​connectors at the joint of the pipe pile.

[0058] like Figure 11 As shown, the design value of the shear load of the snap-fit ​​connector 3 under horizontal load on the pipe pile foundation is... In the formula This represents the design value of the horizontal load for the pipe pile foundation, in kN. Earth pressure on the top surface of the i-th layer of soil on the active side of the pipe pile Unit: kN / m 2 ; Earth pressure at the bottom 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 meters; n is the number of soil layers through which the horizontal load passes to the pipe pile joint.

[0059] like Figure 12 As shown, under bending moment load, the pipe pile foundation exhibits a relationship due to the linear stress distribution at the pipe pile joints. The design value of the tensile load of the buckle connector 3, which is subjected to the greatest tensile force, is... In the formula The design value of the bending moment load of the pipe pile joint is given in kN·m. The first one on one side of the neutral axis of the pipe pile The design value of the tensile load of the snap-fit ​​connector 3 Unit: kN; The first one on one side of the neutral axis of the pipe pile The distance between each snap-fit ​​connector 3 and the neutral axis of the pipe pile, in meters; The distance between the snap-fit ​​connector 3, which is furthest from the neutral axis of the pipe pile, and the neutral axis of the pipe pile is expressed in meters. The neutral axis of the pipe pile is the axis on which the normal stress of the pipe pile cross section is zero. Tensile stress and compressive stress are on both sides of the neutral axis of the pipe pile, respectively.

[0060] like Figure 7 , Figure 13 As shown, the tensile stress on the abdominal side of the snap-fit ​​connector 3 , In the formula The width of the abdomen of the snap fastener 3 is in meters (m). The length of expansion joint 302 is in meters (m). The length of the snap-fit ​​connector 3 is in meters (m). The tensile yield strength of the material of the snap-fit ​​connector 3 is given in kN / m. 2 ;

[0061] Abdominal shear stress of snap-fit ​​connector 3 , In the formula The shear yield strength of the material for the snap-fit ​​connector 3 is given in kN / m. 2 ;

[0062] like Figure 7 , Figure 14 As shown, the tensile force of the snap-fit ​​connector 3 Shear stress at the shear interface of the two wings Balance, thus the shear stress on both wings , In the formula The height of the two wings of the snap fastener 3 is in meters (m).

[0063] Based on the above-mentioned snap-fit ​​pipe pile joint and its corresponding design method, when performing pile splicing operations on the construction site, the slag in the installation groove 4 on the end plate 101 should be cleaned before pile driving. Pipe piles 1 with a diameter of 600mm or less can be driven by hammer driving or static pressure driving, while pipe piles 1 with a diameter of more than 600mm can be driven by pile planting. When splicing, the lower section of pipe pile 1 is driven in first. When the top surface of the lower section of pipe pile 1 is about 1.0m above the ground, the upper section of pipe pile 1 is hoisted. When the axes of the upper and lower sections of pipe pile 1 are completely coincident on a vertical line and the upper and lower installation grooves 4 are aligned to form an installation cavity, the snap-fit ​​connector 3 is driven into each installation cavity with a hammer until the snap 301 on the snap-fit ​​connector 3 is completely embedded in the snap 402, so that the snap-fit ​​connector 3 is automatically locked in the installation cavity, thereby completing the pile splicing construction. During the pile splicing process, it is only necessary to align the mounting grooves 4 on the upper and lower end plates 101 to form a closed mounting cavity. Then, the snap-fit ​​connector 3 is driven into the mounting cavity from the outer circumference of the end plate 101 along the radial direction of the end plate 101 towards the center of the end plate 101. Compared with the traditional mechanical vertical connection, the splicing difficulty is small and the splicing speed is faster. The entire joint is simple to manufacture. By changing the line connection of the welded joint and the point connection of the traditional mechanical connection to the surface connection of the snap-fit ​​connector 3, the joint is subjected to uniform force and has a higher load-bearing capacity.

[0064] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A snap-fit ​​pipe pile connector, characterized in that: Includes pipe piles (1), end plates (101), snap-fit ​​connectors (3), mounting grooves (4), cover plates (401), and snap-fit ​​grooves (402). The pipe piles (1) are fitted with end plates (101) at their ends. Two sections of pipe piles (1) are joined together via the end plates (101). Multiple evenly distributed openings are provided on the end plates (101) along their circumferential direction. These openings extend from the outer circumference of the end plates (101) towards the center of the end plates (101) in the radial direction. The openings on the two joined end plates (101) correspond one-to-one. Cover plates (401) are provided on the opposite surfaces of the two joined end plates (101) at the openings. 401) The opening is closed to form a funnel-shaped mounting groove (4). The two corresponding mounting grooves (4) are joined together to form a closed mounting cavity. The mounting cavity is provided with a snap fastener (3) that is compatible with the mounting cavity. The front end of the mounting cavity is provided with snap fastener grooves (402) on both sides. The front end center of the snap fastener (3) is provided with a deformation joint (302) along the length direction of the snap fastener (3). The front end of the snap fastener (3) protrudes outward at the deformation joint (302) to form a snap fastener (301) that is compatible with the snap fastener groove (402). The snap fastener groove (402) is formed by two grooves joining together. The two grooves are respectively provided on the two joined end plates (101).

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

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

4. The snap-fit ​​pipe pile joint according to claim 1, characterized in that: The length of the expansion joint (302) is more than 1.2 times the length of the clip (301), and the width of the expansion joint (302) is twice the width of the clip (301) plus the installation gap.

5. A design method for a snap-fit ​​pipe pile joint as described in any one of claims 1-4, 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 made by cutting and bending steel plate, and a mounting groove (4) is formed by welding the cover plate (401) at the opening on the end plate (101). The pipe pile reinforcement cage is tied and prestressed steel bars (201) are pre-embedded in the pipe pile reinforcement cage. The end plate (101) is installed at the end of the pipe pile reinforcement cage. The upset head of the prestressed steel bar (201) is anchored in the anchor hole (2) on the end plate (101). The tension bolt is installed at the tension bolt hole (5) and the prestressed steel bar (201) is prestressed through the tension bolt. Then the steel formwork is installed and the pipe pile (1) concrete is poured to complete the prefabrication of the pipe pile (1). Two pipe piles (1) are connected through end plates (101) so that the mounting grooves (4) on the two end plates (101) are connected to form a mounting cavity, and the grooves on the two end plates (101) are connected to form a snap-fit ​​groove (402). Drive the snap fastener (3) into the mounting cavity until the snap fastener (301) on the snap fastener (3) is fully embedded in the snap fastener groove (402); The cross-section and bearing capacity of the snap-fit ​​connector (3) are designed and verified.

6. The design method for the snap-fit ​​pipe pile joint according to claim 5, characterized in that: The front end of the snap fastener (3) is provided with an expansion joint (302). During the process of driving the snap fastener (3) into the installation cavity, the expansion joint (302) shrinks. After the snap fastener (301) on the snap fastener (3) is fully embedded in the snap fastener groove (402), the expansion joint (302) recovers and the snap fastener (3) automatically locks.

7. The design method for the snap-fit ​​pipe pile joint according to claim 5, characterized in that, When performing design verification of the cross-section and bearing capacity of the snap-fit ​​connector (3), the following should be included: The design value of the tensile load of the snap-fit ​​connector under the action of pull-out load in the pipe pile foundation. In the formula, N is the design value of the pull-out load of the pipe pile foundation, in kN; The side wall friction of the pipe pile, in kN / m 2 ; The length of the pipe pile section is in meters (m). The radius of the pipe pile is in meters. This refers to the number of snap-fit ​​connectors at the joint of the pipe pile; The design value of the shear load of the snap-fit ​​connector (3) under horizontal load on the pipe pile foundation. In the formula This represents the design value of the horizontal load for the pipe pile foundation, in kN. Earth pressure on the top surface of the i-th layer of soil on the active side of the pipe pile Unit: kN / m 2 ; Earth pressure at the bottom of the i-th layer of soil on the active side of the pipe pile Unit: kN / m 2 ; The thickness of the i-th soil layer is in meters; n is the number of soil layers through which the horizontal load passes to the pipe pile joint. Under bending moment load, the pipe pile foundation exhibits a relationship due to the linear stress distribution at the pipe pile joints. The design value of the tensile load of the snap fastener (3) with the greatest tensile force is... In the formula The design value of the bending moment load of the pipe pile joint is given in kN·m. The first one on one side of the neutral axis of the pipe pile Design value of tensile load for each snap-fit ​​connector (3) Unit: kN; The first one on one side of the neutral axis of the pipe pile The distance between each snap-fit ​​connector (3) and the neutral axis of the pipe pile, in meters; The distance between the snap-fit ​​connector (3) furthest from the neutral axis of the pipe pile and the neutral axis of the pipe pile, in meters; Tensile stress on the abdomen of the snap-fit ​​connector (3) , In the formula The width of the abdomen of the snap fastener (3) is in meters; The length of the expansion joint (302) is in meters (m). The length of the snap-fit ​​connector (3) is in meters (m). The tensile yield strength of the material of the snap-fit ​​connector (3) is given in kN / m. 2 ; Abdominal shear stress of snap-fit ​​connector (3) , In the formula The shear yield strength of the material for the snap-fit ​​connector (3) is kN / m. 2 ; Shear stress on both wings of the snap-fit ​​connector (3) , In the formula The height of the two wings of the snap fastener (3) is in meters.

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