Dumbbell pin plug pipe pile joint and design method thereof

Abstract

The present application relates to a kind of dumbbell pin bolt pipe pile joint and its design method, dumbbell pin bolt pipe pile joint includes upper section pipe pile, lower section pipe pile, upper end plate, lower end plate and dumbbell pin bolt, it is uniformly distributed to be equipped with multiple prestressed tendon anchorage hole on the upper end plate and lower end plate along circumference, it is equipped with opening between adjacent two prestressed tendon anchorage holes, it is equipped with cover plate on the upper end plate and lower end plate at opening, cover plate is closed to form T-shaped groove to opening, corresponding two T-shaped grooves butt joint form I-shaped pin bolt groove, half-round fastening hole is equipped in one side of pin bolt groove, dumbbell pin bolt is equipped in pin bolt groove and is adapted to pin bolt groove, and fastening pin is hit into fastening hole to lock dumbbell pin bolt.The beneficial effects of the present application are that the vertical socket connection of the commonly used mechanical joint is changed to horizontal pin connection, the linear connection of the welded joint and the point connection of the vertical pin connection are changed to surface connection, the joint is simple to manufacture, the stress is uniform, and the bearing capacity is higher.

Description

Technical Field

[0001] This invention relates to the field of pile foundation engineering technology, specifically to a dumbbell pin-type pipe pile joint and its design method. Background Technology

[0002] Prestressed concrete pipe piles are typically spliced ​​using welding and mechanical joints. Welding is the most common method, but weld quality defects can affect the pile's bearing capacity. The weld between the two end plates of the pipe pile joint is a circumferential contact with a small contact area, resulting in a joint bearing capacity generally lower than the pile's bearing capacity. Furthermore, uneven weld thickness affects the verticality of the pipe pile. Welded joints also consume significant time during pile driving, requiring 30-60 minutes for weld application and cooling. Mechanical joints offer various splicing methods. Commonly used mechanical joints employ a vertical insertion design, using racks or pinions for vertical connection and horizontal spring clamping. The disadvantages of this type of joint include the need for complete alignment of all pins during the connection of upper and lower pipe pile sections, which is time-consuming. Additionally, the use of a socket joint and spring clamping causes a certain amount of opening displacement under vertical pull-out forces and lateral bending moments, reducing the joint's bearing capacity and affecting its durability. The key technical problem that needs to be solved is how to simplify the manufacturing process of pipe piles, facilitate pile splicing during on-site construction, and ensure that the bearing capacity of the pipe pile joints 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 dumbbell-shaped pin-type pipe pile joint and its design method. It transforms the vertical socket connection of commonly used mechanical joints into a horizontal driven pin connection, and transforms the line connection of welded joints and the point connection of vertical pin connections into a surface connection. The joint is simple to manufacture, has uniform stress, and higher load-bearing capacity.

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

[0005] A dumbbell-shaped pin-type pipe pile joint includes an upper pipe pile, a lower pipe pile, an upper end plate, a lower end plate, and a dumbbell-shaped pin. The upper end plate is located at the end of the upper pipe pile, and the lower end plate is located at the end of the lower pipe pile. The upper and lower pipe piles are joined together by the upper and lower end plates. Multiple evenly distributed prestressed tendon anchor holes are formed along the circumference of both the upper and lower end plates. An opening is provided between adjacent prestressed tendon anchor holes on both the upper and lower end plates, extending radially from the outer circumference of the end plate towards its center. The opposite surfaces of the upper and lower end plates are positioned at the top. A cover plate is provided at each opening, and the cover plate closes the opening to form a T-shaped groove. The T-shaped grooves on the upper end plate and the T-shaped grooves on the lower end plate correspond one-to-one. The two corresponding T-shaped grooves are joined together to form an I-shaped pin groove. A semi-circular fastening hole is provided on one side of the pin groove at the junction of the upper end plate (101) and the lower end plate (201). The fastening hole is formed by two arc-shaped grooves respectively provided on the upper end plate and the lower end plate. An I-shaped dumbbell pin is provided in the pin groove to match the pin groove. A fastening pin (4) is driven into the fastening hole to lock the dumbbell pin (3).

[0006] Furthermore, the opening has a T-shaped cross-section, the cover plate has a rectangular cross-section, and the bottom surface of the cover plate is welded to the surface of the end plate.

[0007] Furthermore, the opening has a rectangular cross-section, the cover plate has an inverted U-shaped cross-section, and the inner space of the cover plate and the opening form a T-shaped groove.

[0008] Furthermore, the dumbbell pin gradually tapers from its outer end to its inner end, forming a 1° to 3° taper along its length. The inner end of the dumbbell pin is inserted into the pin groove, and the outer end face of the dumbbell pin is a cylindrical surface that fits the outer wall of the pipe pile.

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

[0010] When precast pipe piles, the installation position of the wing plate (303) of the dumbbell pin (3) is determined according to the thickness of the end plate. Then, an opening and an arc groove are cut on the end plate, and a cover plate (102) is welded at the opening to form a T-groove.

[0011] Align the upper end plate (101) and the lower end plate (201), and connect the upper section pipe pile (1) and the lower section pipe pile (2) so that the T-slots on the upper end plate (101) and the lower end plate (201) are connected to form a pin groove (301), and the arc grooves on the upper end plate (101) and the lower end plate (201) are connected to form a fastening hole (401).

[0012] Drive the dumbbell pin (3) into the pin groove (301), and then drive the fastening pin (4) into the fastening hole (401) to lock the dumbbell pin (3).

[0013] The pipe pile joints are designed and their bearing capacity is verified.

[0014] Furthermore, when the end plate thickness is greater than 20mm, a T-shaped opening is cut into the end plate at the designed location of the pin groove, and then a rectangular cover plate is welded at the opening so that the flange of the dumbbell pin is flush with the end plate surface after the dumbbell pin is driven in; when the end plate thickness is less than 20mm, a rectangular opening is cut into the end plate at the designed location of the pin groove, and then an inverted U-shaped cover plate is welded at the opening so that the flange of the dumbbell pin is placed on the end plate after the dumbbell pin is driven in.

[0015] Furthermore, the length of the dumbbell pin (3) is 2 / 3 to 3 / 4 of the width of the end plate.

[0016] Furthermore, the design and bearing capacity verification of pipe pile joints include:

[0017] The design value of the tensile load of the dumbbell pin in a pipe pile foundation under pull-out load. In the formula This represents the design value of the pull-out load for the pipe pile foundation, in kN. Frictional resistance of the pipe pile sidewall, unit: kN / m 2 , The length of the pipe pile section is in meters (m). The radius of the pipe pile is in meters. The number of dumbbell pins at the pipe pile joint;

[0018] Design value of shear load on dumbbell pin in pipe pile foundation under horizontal load In the formula This represents the design value of the horizontal load on the pipe pile foundation, in kN. and These are the top surface earth pressure and bottom surface earth pressure of the i-th layer of soil on the active side of the pipe pile, respectively. ), 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.

[0019] 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 dumbbell pin with the greatest tensile force is... In the formula This represents the design value of the bending moment load at the pipe pile joint, in kN·m. The first one on one side of the neutral axis Design value of tensile load on each dumbbell pin ( ), unit kN, The first one on one side of the neutral axis The distance from the dumbbell pin to the neutral axis, in meters. The distance between the dumbbell pin furthest from the neutral axis and the neutral axis, in meters;

[0020] Design value of web tensile bearing capacity of dumbbell pin , + In the formula The tensile yield strength of the dumbbell pin material, in kN / m. 2 ; Width of the web of the dumbbell pin, in meters (m). The length of the dumbbell pin, in meters;

[0021] Design value of web shear capacity of dumbbell pin , In the formula The shear yield strength of the dumbbell pin material, in kN / m. 2 ;

[0022] Design value of shear capacity of the flange of the dumbbell pin , In the formula The height of the flange of the dumbbell pin, in meters (m).

[0023] Design value of compressive bearing capacity of the flange of the dumbbell pin , In the formula The compressive yield strength of the dumbbell pin material, in kN / m. 2 ; Width of the flange of the dumbbell pin, in meters;

[0024] Design value of shear bearing capacity of pin groove , In the formula The height of the web of the dumbbell pin, in meters (m).

[0025] Design value of compressive bearing capacity of pin groove , .

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. When connecting the upper and lower sections of the pipe pile, this invention only requires aligning half of the open T-shaped groove of the upper end plate with half of the open T-shaped groove of the lower end plate to form an I-shaped closed dumbbell pin groove, which is easier to connect than the traditional mechanical vertical connection.

[0028] 2. This invention completes a pipe pile joint by driving dumbbell-shaped pins horizontally around the perimeter of the pipe pile joint end plate, inserting fastening pins, and tightening with a hammer. This method saves time and increases the jointing speed compared to the vertical socketing method.

[0029] 3. This invention transforms the line connection of the welded joint and the point connection of the traditional mechanical connection into an I-shaped surface connection, which makes the joint simple to manufacture, uniformly stressed, and has high load-bearing capacity. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the connection between the upper and lower sections of the pipe pile in this invention;

[0031] Figure 2 This is a schematic diagram of the upper end plate structure in this invention;

[0032] Figure 3 This is a schematic diagram of the installation of the dumbbell pin in this invention. Figure 1 ;

[0033] Figure 4 This is a schematic diagram of the installation of the dumbbell pin in this invention. Figure 2 ;

[0034] Figure 5 for Figure 3 A cross-sectional schematic diagram, with the fastening pins removed from the diagram;

[0035] Figure 6 for Figure 4 A cross-sectional schematic diagram, with the fastening pins removed from the diagram;

[0036] Figure 7 This is a three-dimensional structural diagram of the dumbbell pin in this invention;

[0037] Figure 8 This is a schematic diagram of the pull-out stress of the dumbbell pin-type pipe pile joint in this invention;

[0038] Figure 9 This is a schematic diagram of the shear stress of the dumbbell pin-type pipe pile joint in this invention;

[0039] Figure 10 This is a schematic diagram of the bending stress of the dumbbell pin-type pipe pile joint in this invention.

[0040] In the diagram: 1. Upper section pipe pile; 101. Upper end plate; 102. Cover plate; 103. Weld; 2. Lower section pipe pile; 201. Lower end plate; 3. Dumbbell pin; 301. Pin groove; 302. Web plate; 303. Wing plate; 4. Fastening pin; 401. Fastening hole; 5. Prestressed tendon anchorage hole. Detailed Implementation

[0041] 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.

[0042] When splicing pipe piles, two pipe piles that are to be joined together are divided into an upper pipe pile 1 and a lower pipe pile 2. The upper and lower pipe piles are joined together by end plates at the ends of the pile bodies. The two end plates are divided into an upper end plate 101 and a lower end plate 201. The upper end plate 101 is fixed to the end of the upper pipe pile 1, and the lower end plate 201 is fixed to the end of the lower pipe pile 2.

[0043] like Figures 1-7 As shown, a dumbbell-shaped pin-type pipe pile joint includes an upper pipe pile 1, a lower pipe pile 2, an upper end plate 101, a lower end plate 201, and a dumbbell-shaped pin 3. The upper pipe pile 1 and the lower pipe pile 2 are connected by the upper end plate 101 and the lower end plate 201. Multiple evenly distributed prestressed tendon anchoring holes 5 are opened along the circumference on both the upper end plate 101 and the lower end plate 201. During the prefabrication of the pipe pile, the prestressed tendons inside the pipe pile are anchored to the end plate through the prestressed tendon anchoring holes 5, thereby fixing the end plate to the end of the pipe pile. An opening is provided between two adjacent prestressed tendon anchorage holes 5 on the upper end plate 101 and the lower end plate 201. The opening extends from the outer circumference of the end plate along the radial direction of the end plate towards the center of the end plate. Cover plates 102 are welded to the openings on the opposite sides of the upper end plate 101 and the lower end plate 201 to form welds 103. The openings are closed by the cover plates 102 to form T-slots. The T-slots on the upper end plate 101 and the T-slots on the lower end plate 201 correspond one-to-one. During pile splicing, the two corresponding T-slots are joined together to form an I-shaped pin groove 301. An arc-shaped groove is provided on the upper end plate 101 and the lower end plate 201 on one side of the pin groove 301 along the length of the pin groove 301. During pile splicing, the two arc-shaped grooves are joined at the junction of the upper end plate 101 and the lower end plate 201 to form a semi-circular fastening hole 401. After the upper section of pipe pile 1 and the lower section of pipe pile 2 are joined, an I-shaped dumbbell pin 3 that is compatible with the pin groove 301 is driven into the pin groove 301. Then, a fastening pin 4 is driven into the fastening hole 401 to lock the dumbbell pin 3, thus completing the pile splicing.

[0044] like Figure 3 , Figure 5 As shown, the cross-section of the opening can be T-shaped, and the cross-section of the cover plate 102 is correspondingly rectangular. The bottom surface of the cover plate 102 is welded to the surface of the end plate. After the cover plate 102 is welded to the upper end plate 101 and the lower end plate 201, the cover plate 102 closes the opening to form a T-shaped groove.

[0045] like Figure 4 , Figure 6 As shown, the cross-section of the opening can also be rectangular, and the cross-section of the cover plate 102 is correspondingly inverted U-shaped. After the cover plate 102 is welded onto the upper end plate 101 and the lower end plate 201, the inner space of the cover plate 102 and the opening form a T-shaped groove.

[0046] like Figure 7As shown, the dumbbell pin 3 is welded from the web plate 302 and the wing plate 303. In order to facilitate the insertion of the dumbbell pin 3 into the pin groove 301, the outer end of the dumbbell pin 3 gradually tapers from the inner end and forms a taper of 1° to 3° along the length direction. When the dumbbell pin 3 is inserted, the inner end of the dumbbell pin 3 is inserted into the pin groove 301. The outer end face of the dumbbell pin 3 is a cylindrical surface that is adapted to the outer wall of the pipe pile.

[0047] A design method for the above-mentioned dumbbell-shaped pin-type pipe pile joint includes:

[0048] (1) When prefabricating pipe piles, the installation position of the wing plate 303 of the dumbbell pin 3 is determined according to the thickness of the end plate. Then, an opening and an arc groove are cut on the end plate, and a cover plate 102 is welded at the opening to form a T-shaped groove.

[0049] Specifically, such as Figure 3 , Figure 5 As shown, when the end plate thickness is greater than 20mm, a T-shaped opening is cut into the end plate at the designed position of the pin groove 301. Then, a rectangular cover plate 102 is welded to the opening so that the flange 303 of the dumbbell pin 3 is flush with the end plate surface after the dumbbell pin 3 is driven in. Figure 4 , Figure 6 As shown, when the end plate thickness is less than 20mm, a rectangular opening is cut into the end plate at the designed position of the pin groove 301. Then, a cover plate 102 with an inverted U-shaped cross-section is welded at the opening, so that the wing plate 303 of the dumbbell pin 3 rests on the end plate after the dumbbell pin 3 is driven in. In this embodiment, the thickness of the cover plate 102 is not less than 1 / 2 of the end plate thickness, the width of the cover plate 102 is the width of the pin groove 301 + 2 times the thickness of the cover plate 102, and the length of the cover plate 102 is equal to the length of the dumbbell pin 3.

[0050] (2) Align the upper end plate 101 and the lower end plate 201, and connect the upper section of pipe pile 1 and the lower section of pipe pile 2 so that the T-slots on the upper end plate 101 and the lower end plate 201 connect to form a pin groove 301 (with a taper of 1° to 3°), and the arc-shaped grooves on the upper end plate 101 and the lower end plate 201 connect to form a fastening hole 401. In this embodiment, the depth of the pin groove 301 and the fastening hole 401 is 1 / 2 to 2 / 3 of the end plate width, and the number of pin grooves 301 and the number of fastening holes 401 are equal to the number of prestressing tendons in the pipe pile.

[0051] (3) Drive the dumbbell pin 3 into the pin groove 301, and then drive the fastening pin 4 into the fastening hole 401 to lock the dumbbell pin 3. In this embodiment, the length of the dumbbell pin 3 is 2 / 3 to 3 / 4 of the width of the end plate, the thickness of the wing plate 303 of the dumbbell pin 3 is not less than 1 / 2 of the thickness of the end plate, the thickness of the web plate 302 of the dumbbell pin 3 is not less than 1.5 times the thickness of the end plate, and is determined by strength calculation. The installation error of the dumbbell pin 3 is less than 0.5 mm; the diameter of the fastening pin 4 is not less than 1 / 2 of the thickness of the end plate, and the diameter of the fastening hole 401 is slightly larger than the diameter of the fastening pin 4.

[0052] (4) Design and load-bearing capacity calculation of the pipe pile joints. For example... Figures 7-10 As shown, the design and bearing capacity verification of pipe pile joints include:

[0053] like Figure 8 As shown, the design value of the tensile load of dumbbell pin 3 under pull-out load in the pipe pile foundation is... In the formula This represents the design value of the pull-out load for the pipe pile foundation, in kN. Frictional resistance of the pipe pile sidewall, unit: kN / m 2 , The length of the pipe pile section is in meters (m). The radius of the pipe pile is in meters. The number of dumbbell pins 3 at the pipe pile joint.

[0054] like Figure 9 As shown, under horizontal load, the design value of the shear load on the dumbbell pin 3 of the pipe pile foundation is... In the formula This represents the design value of the horizontal load on the pipe pile foundation, in kN. and These are the top surface earth pressure and bottom surface earth pressure of the i-th layer of soil on the active side of the pipe pile, respectively. ), 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.

[0055] like Figure 10 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 dumbbell pin 3, which experiences the greatest tensile force, is... In the formula This represents the design value of the bending moment load at the pipe pile joint, in kN·m. The first one on one side of the neutral axis The design value of tensile load for each dumbbell pin (3) ), unit kN, The first one on one side of the neutral axis The distance from the dumbbell pin 3 to the neutral axis, in meters. The distance between the dumbbell pin 3, which is furthest from the neutral axis, and the neutral axis, is expressed in meters (m).

[0056] Design value of tensile bearing capacity of web plate 302 of dumbbell pin 3 , + In the formula The tensile yield strength of dumbbell pin 3 is given by kN / m. 2 ; Width of the web 302 of dumbbell pin 3, in meters; The length of dumbbell pin 3 is in meters (m).

[0057] Design value of shear bearing capacity of web plate 302 of dumbbell pin 3 , In the formula The shear yield strength of dumbbell pin 3 is given by the material, in kN / m. 2 .

[0058] Design value of shear bearing capacity of flange 303 for dumbbell pin 3 , In the formula The height of the flange 303 of dumbbell pin 3 is in meters.

[0059] Design value of compressive bearing capacity of flange 303 of dumbbell pin 3 , In the formula The compressive yield strength of the material for dumbbell pin 3 is given in kN / m. 2 ; Width of the flange 303 of dumbbell pin 3, in meters.

[0060] Design value of shear bearing capacity of 301 pin groove , In the formula The height of the web 302 of the dumbbell pin 3 is in meters.

[0061] Design value of compressive bearing capacity of pin groove 301 , .

[0062] Based on the above-mentioned dumbbell pin-type pipe pile joint and its corresponding design method, when performing pile splicing operations on the construction site, first drive in one section of pipe pile. When the top surface of the pipe pile is about 1.0m above the ground, stop driving and then use a crane to lift another section of pipe pile. After all the T-slots on the two sections of pipe pile are aligned, drive the dumbbell pins into each pin slot 301, and then drive the fastening pins 4 into the fastening holes 401 to lock the dumbbell pins 3. During the pile splicing process, it is only necessary to align the T-slots on the upper end plate 101 with the T-slots on the lower end plate 201 to form an I-shaped pin slot 301. Then, drive the dumbbell pins 3 into the pin slots 301 from the outer circumference of the end plate along the radial direction towards the center of the end plate. Compared with the traditional mechanical vertical connection, the connection is easier and 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 I-shaped surface connection, the joint is subjected to uniform stress and has high load-bearing capacity.

[0063] 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 dumbbell pin plug pile joint, characterized by: The utility model relates to a kind of pipe pile joint, including upper section pipe pile (1), lower section pipe pile (2), upper end plate (101), lower end plate (201) and dumbbell pin bolt (3), upper end plate (101) is located in upper section pipe pile (1) end part, lower end plate (201) is located in lower section pipe pile (2) end part, upper section pipe pile (1) and lower section pipe pile (2) are butted by upper end plate (101) and lower end plate (201), and upper end plate (101) and lower end plate (201) are all set with a plurality of evenly distributed prestressed tendon anchorage hole (5) along circumference, and upper end plate (101) and lower end plate (201) are all set with opening between adjacent two prestressed tendon anchorage hole (5), and opening extends from end plate peripheral surface to end plate center along end plate radial direction, and the board face of upper end plate (101) and lower end plate (201) is located in opening and is all set with cover plate (102), and cover plate (102) closes opening and forms T-shaped groove, and the T-shaped groove on upper end plate (101) and the T-shaped groove on lower end plate (201) are one to one correspondence, and corresponding two T-shaped grooves are butted to form I-shaped pin bolt groove (301), and one side of pin bolt groove (301) is located in the junction of upper end plate (101) and lower end plate (201) and is provided with semicircular fastening hole (401), and fastening hole (401) is formed by the butt joint of two arc grooves respectively arranged on upper end plate (101) and lower end plate (201), and pin bolt groove (301) is provided with dumbbell pin bolt (3) of I-shaped shape matched with pin bolt groove (301), and fastening pin (4) is driven into fastening hole (401) to lock dumbbell pin bolt (3), and the outer end of dumbbell pin bolt (3) gradually tapers to inner end, and forms 1 ° ~ 3 ° taper along length direction, and the inner end of dumbbell pin bolt (3) is inserted into pin bolt groove (301), and the outer end face of dumbbell pin bolt (3) is cylindrical surface matched with pipe pile outer wall, and the length of dumbbell pin bolt (3) is 2 / 3 ~ 3 / 4 of end plate width.

2. The dumbbell pin plug post joint of claim 1, wherein: The cross section of the opening is T-shaped, the cross section of the cover plate (102) is rectangular, and the bottom surface of the cover plate (102) is welded with the surface of the end plate.

3. The dumbbell pin plug post joint of claim 1, wherein: The cross section of the opening is rectangular, the cross section of the cover plate (102) is inverted U-shaped, and the inner space of the cover plate (102) and the opening form a T-shaped groove.

4. A method of designing a dumbbell pin plug pile joint as claimed in claim 2 or 3, characterized in that, The utility model relates to a kind of pipe pile joint, including upper section pipe pile (1), lower section pipe pile (2), upper end plate (101), lower end plate (201) and dumbbell pin bolt (3), upper end plate (101) is located in upper section pipe pile (1) end part, lower end plate (201) is located in lower section pipe pile (2) end part, upper section pipe pile (1) and lower section pipe pile (2) are butted by upper end plate (101) and lower end plate (201), and upper end plate (101) and lower end plate (201) are all set with a plurality of evenly distributed prestressed tendon anchorage hole (5) along circumference, and upper end plate (101) and lower end plate (201) are all set with opening between adjacent two prestressed tendon anchorage hole (5), and opening extends from end plate peripheral surface to end plate center along end plate radial direction, and the board face of upper end plate (101) and lower end plate (201) is located in opening and is all set with cover plate (102), and cover plate (102) closes opening and forms T-shaped groove, and the T-shaped groove on upper end plate (101) and the T-shaped groove on lower end plate (201) are one to one correspondence, and corresponding two T-shaped grooves are butted to form I-shaped pin bolt groove (301), and one side of pin bolt groove (301) is located in the junction of upper end plate (101) and lower end plate (201) and is provided with semicircular fastening hole (401), and fastening hole (401) is formed by the butt joint of two arc grooves respectively arranged on upper end plate (101) and lower end plate (201), and pin bolt groove (301) is provided with dumbbell pin bolt (3) of I-shaped shape matched with pin bolt groove (301), and fastening pin (4) is driven into fastening hole (401) to lock dumbbell pin bolt (3), and the outer end of dumbbell pin bolt (3) gradually tapers to inner end, and forms 1 ° ~ 3 ° taper along length direction, and the inner end of dumbbell pin bolt (3) is inserted into pin bolt groove (301), and the outer end face of dumbbell pin bolt (3) is cylindrical surface matched with pipe pile outer wall, and the length of dumbbell pin bolt (3) is 2 / 3 ~ 3 / 4 of end plate width. Cutting opening and arc groove on end plate, and welding cover plate (102) at opening to form T-shaped groove according to end plate thickness to determine the installation position of wing plate (303) of dumbbell pin bolt (3) when prefabricating pipe pile; Align upper end plate (101) and lower end plate (201), butt joint upper section pipe pile (1) and lower section pipe pile (2) to make T-shaped groove on upper end plate (101) and lower end plate (201) butt joint to form pin bolt groove (301), and arc groove on upper end plate (101) and lower end plate (201) butt joint to form fastening hole (401); Drive dumbbell pin bolt (3) into pin bolt groove (301), then drive fastening pin (4) into fastening hole (401) to lock dumbbell pin bolt (3); Design and bearing capacity checking calculation are carried out to pipe pile joint.

5. The method of designing a dumbbell pin plug post joint according to claim 4, wherein: When the thickness of the end plate is greater than 20mm, cut the end plate at the designed position of the pin bolt groove (301) to form a T-shaped opening, and then weld a rectangular cover plate (102) at the opening, so that the wing plate (303) of the dumbbell pin bolt (3) is flush with the end plate after the dumbbell pin bolt (3) is driven in; when the thickness of the end plate is less than 20mm, cut the end plate at the designed position of the pin bolt groove (301) to form a rectangular opening, and then weld an inverted U-shaped cover plate (102) at the opening, so that the wing plate (303) of the dumbbell pin bolt (3) is placed on the end plate after the dumbbell pin bolt (3) is driven in.

6. The method of designing a dumbbell pin plug post joint according to claim 4, wherein, When designing and checking the bearing capacity of the pipe pile joint, the following are included: The tensile load design value of the dumbbell pin bolt (3) under the pull-out load of the pipe pile foundation , wherein is the pipe pile foundation pull-out load design value, in kN; is the pipe pile sidewall friction, in kN / m 2 , is the pipe pile section length, in m; is the pipe pile radius, in m, is the number of dumbbell pin bolts (3) at the pipe pile butt joint. Under horizontal load, the design value of the shear load on the dumbbell pin (3) of the pipe pile foundation. In the formula This represents the design value of the horizontal load on the pipe pile foundation, in kN. and These are the top surface earth pressure and bottom surface earth pressure of the i-th layer of soil on the active side of the pipe pile, respectively. ), 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 dumbbell pin (3) with the greatest tensile force is... In the formula This represents the design value of the bending moment load at the pipe pile joint, in kN·m. The first one on one side of the neutral axis The design value of tensile load for each dumbbell pin (3) ), unit kN, The first one on one side of the neutral axis The distance from the dumbbell pin (3) to the neutral axis, in meters. The distance between the dumbbell pin (3) furthest from the neutral axis and the neutral axis, in meters; The design value of the tensile load bearing capacity of the web (302) of the dumbbell pin (3) , , wherein is the tensile yield strength of the material of the dumbbell pin (3) in kN / m 2 ; is the width of the web (302) of the dumbbell pin (3) in m; is the length of the dumbbell pin (3) in m; Design value of web (302) shear capacity of dumbbell pin (3) , , where is the material shear yield strength of dumbbell pin (3) in kN / m 2 ; Shear capacity design value of the wing plate (303) of the dumbbell-shaped pin (3) , , wherein is the height of the wing plate (303) of the dumbbell-shaped pin (3), in meters; The design value of the compression bearing capacity of the wing plate (303) of the dumbbell pin (3) , , wherein is the compressive yield strength of the material of the dumbbell pin (3), in kN / m 2 ; is the width of the wing plate (303) of the dumbbell pin (3), in m; Design value of shear resistance of pin groove (301) , , wherein is the height of the web (302) of the dumbbell pin (3) in meters. Compression load bearing capacity design value of pin groove (301) , .

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