Mechanical self-locking concrete precast pile joint structure and construction method

Abstract

The application discloses a mechanical self-locking type concrete precast pile joint structure and a construction method, which comprises an upper end plate, a lower end plate and a connecting structure composed of an upper sleeve, a lower sleeve, two groups of wedge pieces, two groups of positioning rings and two connecting steel bars; the connecting structure has multiple groups and is arranged between longitudinal steel bars in an upper precast pile and a lower precast pile respectively, and is used for connecting the upper precast pile and the lower precast pile. The longitudinal steel bars in adjacent concrete precast piles are mechanically connected one by one by the sleeve, the connecting steel bar, the positioning ring and the wedge piece; the force transmission of the longitudinal steel bars in the precast piles is direct and reliable; after the piles are connected, the longitudinal steel bars in the upper and lower pile bodies are mechanically self-locked; the longitudinal steel bars after connection cannot be pulled apart; the safe and reliable, convenient construction and low-cost goal of the concrete precast pile joint is achieved; and meanwhile, the construction method can also be used for connecting concrete components such as concrete precast columns and concrete precast shear walls.

Description

Technical Field

[0001] This invention relates to the field of precast concrete pile technology in building engineering, and more specifically to a mechanically self-locking precast concrete pile splicing structure and construction method. Background Technology

[0002] Precast concrete piles are a common type of foundation pile in construction engineering. Common types of precast concrete piles include hollow pipe piles and solid square piles.

[0003] Due to limitations in production and transportation conditions, the length of a single precast concrete pile cannot be too long. When the designed pile length of a building foundation exceeds the length of a single precast pile, it is necessary to splice the precast concrete piles. That is, during the pile driving process, the individual precast piles are connected vertically to form a vertically continuous precast pile with a total length that meets the design requirements.

[0004] Currently, the main method for extending precast concrete piles is the steel structure welding splicing method. This involves installing a steel structure pile head at the end of the precast concrete pile. During splicing, the steel structure pile heads of adjacent precast piles are welded together on-site to form a single unit, thus extending the precast concrete pile.

[0005] The main disadvantages of the welded splicing method for precast concrete piles in steel structures are:

[0006] 1) When producing a single precast concrete pile, a steel structure pile head for welding connection needs to be set at the end of the precast pile, which increases the cost of the precast concrete pile and the difficulty of its production.

[0007] 2) When splicing precast piles, on-site welding is required during pile driving. During welding, the upper section of the precast pile is in a hoisted state, and the on-site construction conditions are complex and difficult. In addition, the on-site climate environment is variable, making it difficult to guarantee the welding quality. On-site welding increases the difficulty and cost of precast pile construction.

[0008] 3) In the steel structure welded pile splicing method, the longitudinal steel bars in the adjacent precast concrete pile bodies need to be indirectly connected through the steel structure pile head and weld. The force transmission path of the longitudinal steel bars in the pile body is indirect and complex, the force transmission reliability is poor, and the integrity and stiffness of the pile body are poor after splicing.

[0009] 4) The steel structure welding splicing method cannot guarantee that the contact surfaces of adjacent precast piles are completely pressed together. Due to factors such as the thermal deformation that may be caused by steel welding, the limited weld size, and the difficulty in guaranteeing welding quality, the axial stiffness of the pile body may be weak, which may easily lead to pile quality problems during pile quality inspection.

[0010] Therefore, the commonly used welding splicing method for precast concrete piles has many drawbacks. In order to ensure the splicing quality of precast concrete piles and achieve safe, reliable, convenient, and cost-effective splicing connections, it is necessary to develop new splicing methods and technologies for precast concrete piles. Summary of the Invention

[0011] The purpose of this invention is to disclose a mechanically self-locking precast concrete pile splicing structure and construction method to solve the above-mentioned drawbacks and achieve the goals of safe, reliable, convenient, and low-cost splicing of precast concrete piles. At the same time, the construction method proposed in this invention can also be used for the connection of concrete components such as precast concrete columns and precast concrete shear walls.

[0012] To achieve the above objectives, the present invention provides a mechanically self-locking precast concrete pile splicing structure, comprising:

[0013] The upper end plate and the lower end plate are fixedly arranged at the bottom of the upper section of the precast pile and the top of the lower section of the precast pile respectively during the precast pile production stage, and both are the same size as the pile body cross-section. Sleeve positioning holes are opened on the end plates corresponding to the position of each longitudinal steel bar in the pile body.

[0014] Multiple sets of connecting structures are respectively arranged between the longitudinal reinforcement bars in the upper and lower precast piles to connect the upper and lower precast piles. Each set includes:

[0015] The upper sleeve and the lower sleeve are fixedly formed in the upper section of the precast pile and the lower section of the precast pile respectively during the precast pile manufacturing stage, and are symmetrical structures. The top of the upper sleeve is mechanically connected to the bottom section of the longitudinal steel bar in the upper section of the precast pile, and the bottom is the opening end of the sleeve and is fixedly received in the sleeve positioning hole of the upper end plate. The bottom of the lower sleeve is mechanically connected to the top section of the longitudinal steel bar in the lower section of the precast pile, and the top is the opening end of the sleeve and is fixedly received in the sleeve positioning hole of the lower end plate.

[0016] Both sets of sleeves have a frustum-shaped chamber with an inner diameter that gradually decreases toward the opening end.

[0017] Two sets of wedges are vertically arranged on the vertical center line of the chambers of the upper sleeve and the lower sleeve, respectively. The thinner end of each wedge is the wedge head and both are arranged facing the cylinder opening.

[0018] Two sets of positioning rings are respectively arranged on the outer side of the heads of the two wedges, and can be accommodated in the positioning hole of the sleeve and connected to the opening end of the sleeve. The positioning rings are divided by the wedges to form two sets of symmetrical positioning ring holes, so that the two sets of connecting steel bars can slide through.

[0019] Two connecting steel bars are arranged symmetrically side by side, with an arc-shaped cross-section and an arc-shaped surface on opposite sides. The ends of the two connecting steel bars can be inserted into the sleeve after passing through the positioning ring simultaneously. They are symmetrically distributed on both sides of the wedge and undergo bending deformation under the limiting and guiding of the wedge and the positioning ring.

[0020] The length of the connecting steel rod is less than the distance between the bottom ends of the upper sleeve and the lower sleeve's frustum-shaped conical chamber;

[0021] The tensile strength of the connecting steel bar is not lower than the tensile strength of the longitudinal steel bar.

[0022] As a further improvement of the present invention, the opposite sides of the two connecting steel bars are flat and are provided with a positioning structure. The positioning structure includes a protrusion and a groove respectively located at the center of the opposite sides of the two connecting steel bars. The protrusion and the groove can cooperate to position and lock the two connecting steel bars.

[0023] As a further improvement of the present invention, both the upper sleeve and the lower sleeve include a connecting section and a sleeve section; the connecting section is a hollow cylindrical structure for connecting with the longitudinal reinforcing bars in the precast pile, and the sleeve section is a hollow cylindrical structure with a frustum conical cavity inside for installing and fixing connecting steel bars.

[0024] As a further improvement of the present invention, when the longitudinal reinforcement in the precast pile is ordinary reinforcement, the inner wall of the splice section can be provided with internal threads, the longitudinal reinforcement connection section is provided with external threads, and the splice section and the longitudinal reinforcement are connected by threads.

[0025] When the longitudinal reinforcement in the precast pile is prestressed steel strand, the inner wall of the splice section can be provided with internal threads, and the sleeve splice section and the prestressed steel strand are connected by cold extrusion.

[0026] As a further improvement of the present invention, the wedge and the positioning ring are integrally cast, so that the two ends of the head of the wedge are fixedly connected to the inner wall of the positioning ring.

[0027] As a further improvement of the present invention, the two ends of the wedge head are fixedly connected to the inner wall of the positioning ring by welding.

[0028] As a further improvement of the present invention, the positioning ring is circular in shape, the contact surface between the sleeve end and the positioning ring is located inside the sleeve positioning hole of the end plate, and the outer surface of the positioning ring does not protrude from the outer surface of the end plate.

[0029] As a further improvement of the present invention, the frontal projection of the positioning ring hole is arc-shaped, and the arc-shaped sag of the cross section of the connecting steel rod is less than the sag of the positioning ring hole, so that the connecting steel rod can freely pass through the positioning ring hole.

[0030] As a further improvement of the present invention, the outer diameter of the sleeve section is larger than the outer diameter of the connecting section, and the slope of the angle between the generatrix of the frustoconical cavity on the inner wall of the sleeve section and the central axis is about 1 / 50-1 / 20.

[0031] This invention also discloses a construction method for a mechanically self-locking precast concrete pile splicing structure, comprising the following steps:

[0032] S1 component processing; First, precast piles with sleeves and end plates, as well as connecting steel bars, positioning rings and wedges are processed and manufactured in the factory;

[0033] S2 Pile Splicing Preparation: The precast piles are driven into place at the construction site. After the precast piles are driven into place, preparations for pile splicing are made.

[0034] S3 mounting and connection accessories;

[0035] Align the two connecting steel bars, install a set of positioning rings and a set of wedges at the ends of the two connecting steel bars respectively, so that the ends of the connecting steel bars pass through the positioning ring holes and the heads of the wedges are inserted between the two connecting steel bars. The two connecting steel bars are positioned and connected by the positioning structure on opposite sides, so that the connecting steel bars, positioning rings and wedges together form a set of connecting accessories.

[0036] S4 Pre-installation and positioning of precast pile connection structure; Remove the plastic protective cap inside the lower sleeve, pre-fit one end of multiple sets of connecting accessories with each lower sleeve of the precast pile, so that the wedge at the bottom of each set of connecting accessories and the end of the connecting steel rod are placed inside each lower sleeve, and the positioning ring is placed on the opening of each lower sleeve to form preliminary positioning.

[0037] S5 Install the precast pile; remove the plastic protective cap inside the upper sleeve, hoist the upper precast pile above the lower precast pile, and align them vertically. Connect the other ends of multiple sets of connecting fittings to each upper sleeve of the upper precast pile, so that the wedges, positioning rings and the ends of the connecting steel bars at the top of each set of connecting fittings are aligned with the opening of the upper sleeve. By slowly lowering the upper precast pile, the two ends of the connecting steel bars are gradually pressed into the truncated cone-shaped chamber of the upper and lower sleeves by gravity settlement. Under the constraint of the two sets of positioning rings and wedges, the connecting steel bars are bent and deformed as a whole, and their outer side is squeezed and locked to the inner wall of the truncated cone-shaped chamber, thus realizing the connection between the upper and lower precast piles.

[0038] The upper and lower precast piles of S6 are connected and secured; the driving of the upper precast piles continues. Under the strong downward pressure of the upper precast piles, the connection between the upper and lower precast piles will be further tightened, so that the sleeve, connecting steel bar and wedge are completely locked, and the upper and lower precast piles are completely and reliably connected.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] (1) A mechanical self-locking precast concrete pile splicing structure and construction method, which uses a sleeve, connecting steel bar, positioning ring and wedge to directly mechanically connect the longitudinal steel bars in adjacent precast concrete piles one by one. The longitudinal steel bars in the precast piles transmit force directly and reliably. After splicing, the longitudinal steel bars in the upper and lower piles are mechanically self-locked and will not be pulled apart. Since the head of the wedge is fixed on the positioning ring, during the splicing process, as the upper precast pile falls continuously under its own weight, the sleeve will push the positioning ring to move towards the middle of the connecting steel bar, and the positioning ring will pull the wedge to move towards the middle of the connecting steel bar. Then, the mechanical locking connection is automatically achieved by the falling action of the upper precast pile under its own weight. No manual intervention is required during the connection process, and no welding or bolting is required. The construction and installation are convenient and easy. Due to the special mechanical self-locking structure, the adjacent precast piles can only move closer to each other during the splicing process and cannot move away from each other. Therefore, during the pile driving process, the adjacent precast piles will only be pressed tighter and tighter and there will be no gap in the axial direction, which is conducive to ensuring the quality of the pile after splicing.

[0041] (2) The precast concrete pile splicing structure of the present invention has a simple structure, does not require a complex steel pile head, and has no outward reinforcing bars. The precast piles are convenient to produce, transport and install. Adjacent precast piles are in contact with each other through end plates. Since the end plates are made of steel structure, the surface is flat and the contact area is large. Under the action of pile driving pressure, the contact surface of the end plates will automatically press together. Therefore, after the pile is spliced, the pile body can reliably transmit the vertical pressure and the axial stiffness of the pile body is large. The splicing components are all made of ordinary steel, the components are simple and the cost is low. They are all inside the pile body and do not affect the pile driving construction and the appearance of the pile body.

[0042] (3) The construction method disclosed in this invention is simple to operate compared with commonly used steel structure welding splicing methods and other splicing methods. The components used are all prefabricated, which makes installation and transportation convenient. It also has high splicing efficiency, strong safety and reliability, and reduces the cost of manual splicing. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the connection relationship after the splicing of a mechanically self-locking precast concrete pile splicing structure and construction method of the present invention, viewed from the main perspective.

[0044] Figure 2 for Figure 1 An explosion diagram;

[0045] Figure 3 This is a plan view of the lower end plate in the mechanical self-locking precast concrete pile splicing structure and construction method of the present invention.

[0046] Figure 4 This is a schematic diagram of the main structure of the upper sleeve in the mechanical self-locking precast concrete pile splicing structure and construction method of the present invention.

[0047] Figure 5 This is a schematic diagram showing the positional relationship between the connecting steel bar and the positioning structure in a mechanical self-locking precast concrete pile splicing structure and construction method of the present invention.

[0048] Figure 6 This is a cross-sectional schematic diagram of the connecting steel bar and the positioning structure at the center of the steel bar in the mechanical self-locking precast concrete pile splicing structure and construction method of the present invention.

[0049] Figure 7 This is a schematic diagram of the wedge and positioning ring in the mechanical self-locking precast concrete pile splicing structure and construction method of the present invention, viewed from the left.

[0050] Figure 8 This is a schematic diagram of the wedge and positioning ring from a bottom-view perspective in the mechanical self-locking precast concrete pile splicing structure and construction method of the present invention.

[0051] In the diagram: 1. Upper precast pile; 2. Lower precast pile; 3. Longitudinal reinforcement; 4. Wedge; 5. Positioning ring; 6. Connecting steel bar; 7. Positioning structure; 11. Upper end plate; 12. Lower end plate; 13. Upper sleeve; 14. Lower sleeve; 41. Wedge head; 51. Positioning ring hole; 71. Protrusion; 72. Groove; 131. Connecting section; 132. Sleeve section; 120. Sleeve positioning hole; 1311. Internal thread; 1320. Frustum conical chamber; 1321. Sleeve opening end. Detailed Implementation

[0052] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0053] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0054] Please refer to Figures 1 to 8 The present invention illustrates a specific embodiment of a mechanically self-locking precast concrete pile splicing structure and construction method.

[0055] A precast pile for a building foundation project is designed to be 16m long, with each pile being 8m long, and requires splicing once. The precast pile is a concrete pipe pile with an outer diameter of 600mm and an inner diameter of 400mm. Eight longitudinal steel bars with a diameter of 20mm are embedded inside the pile.

[0056] A mechanically self-locking precast concrete pile splicing structure includes: an upper end plate 11, a lower end plate 12, and a connection structure consisting of an upper sleeve 13, a lower sleeve 14, two sets of wedges 4, two sets of positioning rings 5, and two connecting steel bars 6.

[0057] In this embodiment, the upper end plate 11 and the lower end plate 12 are fixedly arranged at the bottom of the upper precast pile 1 and the top of the lower precast pile 2, respectively, during the precast pile manufacturing stage, and are both the same size as the pile body cross-section. Sleeve positioning holes 120 are provided on the end plates corresponding to the positions of each longitudinal reinforcing bar 3 in the pile body. Specifically, the end plates are made of 14mm thick steel plates. The end plates are annular in shape, with an inner diameter of 400mm and an outer diameter of 600mm. A total of 8 sleeve positioning holes 120 are provided on the end plates, with a diameter of 40mm, the same as the outer diameter of the sleeve. During precast pile production, the sleeve section 132 is embedded 8mm deep into the end plate to ensure accurate positioning. Anchor bars are provided on the end plates to connect and fix them to the concrete pile body. The outer surface of the end plates is machined to be flat and smooth to ensure a tight fit between adjacent end plates.

[0058] The connecting structure has multiple sets, which are respectively arranged between the longitudinal steel bars 3 in the upper precast pile 1 and the lower precast pile 2, and are used to connect the upper precast pile 1 and the lower precast pile 2.

[0059] Specifically, the upper sleeve 13 and the lower sleeve 14 are fixedly formed in the upper precast pile 1 and the lower precast pile 2 respectively during the precast pile manufacturing stage, and are symmetrical structures. The top of the upper sleeve 13 is mechanically connected to the bottom section of the longitudinal steel bar 3 in the upper precast pile 1, and the bottom is the cylinder opening end 1321, which is fixedly received in the sleeve positioning hole 120 of the upper end plate 11. The bottom of the lower sleeve 14 is mechanically connected to the top section of the longitudinal steel bar 3 in the lower precast pile 2, and the top is the cylinder opening end 1321, which is fixedly received in the sleeve positioning hole 120 of the lower end plate 12. Both sets of sleeves have a frustum-shaped conical cavity 1320 formed in the cylinder body, with the inner diameter gradually decreasing towards the cylinder opening end 1321. Both the upper sleeve 13 and the lower sleeve 14 include a connecting section 131 and a sleeve section 132. The connecting section 131 is a hollow cylindrical structure with an inner diameter of 20mm, outer diameter 30mm, length 40mm, used to connect with the longitudinal reinforcement 3 in the precast pile; when the longitudinal reinforcement 3 in the precast pile is ordinary reinforcement, the inner wall of the connecting section 131 can be provided with internal thread 1311, the connecting section of the longitudinal reinforcement 3 is provided with external thread, and the connecting section 131 and the longitudinal reinforcement 3 are connected by thread; the sleeve section 132 is a hollow cylindrical structure, the outer diameter of the sleeve section 132 is 40mm, the length is 80mm, the inner diameter of the bottom end of the sleeve section 132 is 28mm, which is larger than the inner diameter of the sleeve opening end 1321 of 24mm, and the inside is a frustum conical cavity 1320, used for the installation and fixing of the connecting steel rod 6. The slope of the angle between the generatrix of the frustum conical cavity 1320 on the inner wall of the sleeve section 132 and the central axis is about 1 / 50-1 / 20. Preferably, in this embodiment, the slope of the angle is 1 / 40.

[0060] In this embodiment, it should be understood that two sets of wedges 4 are vertically arranged on the vertical center lines of the chambers of the upper sleeve 13 and the lower sleeve 14, respectively. The thinner end of the wedge 4 is the wedge head 41, and both are arranged facing the cylinder opening 1321. Two sets of positioning rings 5 ​​are respectively arranged outside the two wedge heads 41, and can be accommodated in the sleeve positioning hole 120 and connected to the cylinder opening 1321 of the sleeve. The positioning rings 5 ​​are divided by the wedges 4 to form two sets of symmetrical positioning ring holes 51, so that the two sets of connecting steel rods 6 can slide through. The wedges 4 and the positioning rings 5 ​​are integrally cast, so that the two ends of the wedge heads 41 are fixedly connected to the inner wall of the positioning rings 5. In addition, the two ends of the wedge heads 41 can also be fixedly connected to the inner wall of the positioning rings 5 ​​by welding.

[0061] The positioning ring 5 is circular in shape, with an inner diameter of 24mm, equal to the inner diameter of the sleeve opening, and an outer diameter of 40mm, equal to the outer diameter of the sleeve opening. The thickness of the positioning ring 5 is 4mm. The thickness of the wedge head 41 is 3mm, and the thickness of the wedge tail is 8mm. The width of the wedge head 41 is 24mm, the width of the wedge tail is 24mm, and the length of the wedge 4 is 75mm. The contact surface between the sleeve opening end 1321 and the positioning ring 5 is located within the sleeve positioning hole 120 of the end plate, and the outer surface of the positioning ring 5 does not protrude from the outer surface of the end plate. The outer surface of the wedge 4 is machined to a smooth surface to reduce the coefficient of sliding friction. The frontal projection of the positioning ring hole 51 is arc-shaped, and the arc height of the cross-section of the connecting steel rod 6 is less than the arc height of the positioning ring hole 51, so that the connecting steel rod 6 can freely pass through the positioning ring hole 51.

[0062] Two connecting steel bars 6 are arranged symmetrically side by side, with an arc-shaped cross-section and rounded surfaces on opposite sides. The ends of the two connecting steel bars 6 can simultaneously pass through the positioning ring 5 and be inserted into the sleeve. They are symmetrically distributed on both sides of the wedge 4 and undergo bending deformation under the limiting guidance of the wedge 4 and the positioning ring 5. The diameter of the arc-shaped cross-section of the connecting steel bar 6 is 24mm, which is equal to the inner diameter of the sleeve opening. The sag of the arc is 10mm, which is less than the radius of the arc (12mm) and slightly less than the sag of the positioning ring hole 51 (11mm), so that the connecting steel bar 6 can freely pass through the positioning ring hole 51. The length of the connecting steel bar 6 is 160mm, which is less than the distance between the bottom ends of the frustum-shaped chamber 1320 of the upper sleeve 13 and the lower sleeve 14. The tensile strength of the connecting steel bar 6 is not less than the tensile strength of the longitudinal reinforcing bar 3. The opposite sides of the two connecting steel rods 6 are flat and are provided with a positioning structure 7. The positioning structure 7 includes a protrusion 71 and a groove 72 respectively located at the center of the opposite sides of the two connecting steel rods 6. The protrusion 71 and the groove 72 can cooperate to position and lock the connecting steel rods 6, preventing relative sliding between the connecting steel rods 6.

[0063] Example 2:

[0064] When the longitudinal reinforcing bars 3 in the precast pile are prestressed steel strands, the inner wall of the splice section 131 can be provided with internal threads, and the sleeve splice section 131 and the prestressed steel strands are connected by cold extrusion. All other technical features are the same as in Embodiment 1 and will not be repeated here.

[0065] This invention also discloses a construction method for a mechanically self-locking precast concrete pile splicing structure, comprising the following steps: S1 Component processing; firstly, precast piles with sleeves and end plates, as well as connecting steel bars 6, positioning rings 5, and wedges 4 are processed and manufactured in a factory; S2 Splicing preparation; the precast piles are driven into place at the construction site, and splicing preparation is carried out after the precast piles are driven into place; S3 Installation of connecting accessories; the two connecting steel bars 6 are aligned, and a set of positioning rings 5 ​​and a set of wedges 4 are installed at the ends of the two connecting steel bars 6 respectively, so that the ends of the connecting steel bars 6 pass through the positioning ring holes 51, and the wedge heads 41 are inserted between the two connecting steel bars 6. The connecting steel rod 6 is positioned and connected by the positioning structure 7 on the opposite side, so that the connecting steel rod 6, the positioning ring 5 and the wedge 4 together form a set of connecting accessories; S4 Pre-installation positioning of the precast pile connecting structure; Remove the plastic protective cap inside the lower sleeve 14, and pre-fit one end of the multiple sets of connecting accessories with each lower sleeve 14 of the precast pile, so that the wedge 4 at the bottom of each set of connecting accessories and the end of the connecting steel rod 6 are placed inside each lower sleeve 14, and the positioning ring 5 rests on the opening of each lower sleeve 14 to form preliminary positioning; The plastic protective cap is fixed at the sleeve opening 1321, and its function is to prevent foreign objects from entering the sleeve during the transportation and installation of the precast pile. S5 Install the precast pile; remove the plastic protective cap inside the upper sleeve 13, hoist the upper precast pile above the lower precast pile, and align them vertically. Connect the other ends of multiple sets of connecting fittings to each upper sleeve 13 of the upper precast pile, ensuring that the ends of the wedges 4, positioning rings 5, and connecting steel rods 6 at the top of each set of connecting fittings are aligned with the opening of the upper sleeve 13. By slowly lowering the upper precast pile, gravity settlement gradually presses both ends of the connecting steel rods 6 into the frustum-shaped conical chamber 1320 of the upper sleeve 13 and lower sleeve 14. Under the constraint of the two sets of positioning rings 5 ​​and wedges 4, the connecting steel bar 6 undergoes bending deformation as a whole, and its outer surface is squeezed and locked to the inner wall of the truncated cone-shaped cavity 1320, realizing the connection between the upper and lower precast piles; S6 The connection between the upper and lower precast piles is tightened; The pile driving construction of the upper precast pile continues. Under the strong downward pressure of the upper precast pile driving, the connection between the upper and lower precast piles will be further tightened, so that the sleeve, connecting steel bar 6, and wedges 4 are completely locked, realizing the complete and reliable connection between the upper and lower precast piles.

[0066] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A mechanically self-locking precast concrete pile splicing structure, characterized in that, include: The upper end plate and the lower end plate are fixedly arranged at the bottom of the upper section of the precast pile and the top of the lower section of the precast pile respectively during the precast pile production stage, and both are the same size as the pile body cross-section. Sleeve positioning holes are opened on the end plates corresponding to the position of each longitudinal steel bar in the pile body. Multiple sets of connecting structures are respectively arranged between the longitudinal reinforcement bars in the upper and lower precast piles to connect the upper and lower precast piles. Each set includes: The upper sleeve and the lower sleeve are fixedly formed in the upper section of the precast pile and the lower section of the precast pile respectively during the precast pile manufacturing stage, and are symmetrical structures. The top of the upper sleeve is mechanically connected to the bottom section of the longitudinal steel bar in the upper section of the precast pile, and the bottom is the opening end of the sleeve and is fixedly received in the sleeve positioning hole of the upper end plate. The bottom of the lower sleeve is mechanically connected to the top section of the longitudinal steel bar in the lower section of the precast pile, and the top is the opening end of the sleeve and is fixedly received in the sleeve positioning hole of the lower end plate. Both sets of sleeves have a frustum-shaped chamber with an inner diameter that gradually decreases toward the opening end. Two sets of wedges are vertically arranged on the vertical center line of the chambers of the upper sleeve and the lower sleeve, respectively. The thinner end of each wedge is the wedge head and both are arranged facing the cylinder opening. Two sets of positioning rings are respectively arranged on the outer side of the heads of the two wedges, and can be accommodated in the positioning hole of the sleeve and connected to the opening end of the sleeve. The positioning rings are divided by the wedges to form two sets of symmetrical positioning ring holes, so that the two connecting steel bars can slide through. Two connecting steel bars are arranged symmetrically side by side, with an arc-shaped cross-section and an arc-shaped surface on opposite sides. The ends of the two connecting steel bars can be inserted into the sleeve after passing through the positioning ring simultaneously. They are symmetrically distributed on both sides of the wedge and undergo bending deformation under the limiting and guiding of the wedge and the positioning ring. The length of the connecting steel rod is less than the distance between the bottom ends of the upper sleeve and the lower sleeve's frustum-shaped conical chamber; The tensile strength of the connecting steel bar is not lower than the tensile strength of the longitudinal steel bar; The opposite sides of the two connecting steel bars are flat and are provided with a positioning structure. The positioning structure includes a protrusion and a groove respectively located at the center of the opposite sides of the two connecting steel bars. The protrusion and groove can cooperate to position and lock the two connecting steel bars. The positioning ring is circular in shape. The contact surface between the sleeve opening end and the positioning ring is located inside the sleeve positioning hole of the end plate, and the outer surface of the positioning ring does not protrude from the outer surface of the end plate. The frontal projection of the positioning ring hole is arc-shaped, and the arc height of the cross section of the connecting steel rod is less than the arc height of the positioning ring hole, so that the steel rod can freely pass through the positioning ring hole.

2. The mechanically self-locking precast concrete pile splicing structure according to claim 1, characterized in that, Both the upper sleeve and the lower sleeve include a connecting section and a sleeve section; the connecting section is a hollow cylindrical structure used to connect with the longitudinal reinforcing bars inside the precast pile, and the sleeve section is a hollow cylindrical structure with a frustum conical cavity inside, used for the installation and fixing of connecting steel bars.

3. The mechanically self-locking precast concrete pile splicing structure according to claim 2, characterized in that, When the longitudinal reinforcement in the precast pile is ordinary reinforcement, the inner wall of the splice section can be provided with internal threads, the longitudinal reinforcement connection section is provided with external threads, and the splice section and the longitudinal reinforcement are connected by threads. When the longitudinal reinforcement in the precast pile is prestressed steel strand, the inner wall of the splice section can be provided with internal threads, and the sleeve splice section and the prestressed steel strand are connected by cold extrusion.

4. The mechanically self-locking precast concrete pile splicing structure according to claim 1, characterized in that, The wedge and the positioning ring are integrally cast, so that the two ends of the head of the wedge are fixedly connected to the inner wall of the positioning ring.

5. The mechanically self-locking precast concrete pile splicing structure according to claim 1, characterized in that, The two ends of the wedge head are fixedly connected to the inner wall of the positioning ring by welding.

6. The mechanically self-locking precast concrete pile splicing structure according to claim 2, characterized in that, The outer diameter of the sleeve section is larger than the outer diameter of the connecting section, and the slope of the angle between the generatrix of the frustum-shaped cavity on the inner wall of the sleeve section and the central axis is 1 / 50-1 / 20.

7. A construction method for a mechanically self-locking precast concrete pile splicing structure based on any one of claims 1-6, characterized in that, Includes the following steps: S1 component processing; First, precast piles with sleeves and end plates, as well as connecting steel bars, positioning rings and wedges are processed and manufactured in the factory; S2 Pile Splicing Preparation: The precast piles are driven into place at the construction site. After the precast piles are driven into place, preparations for pile splicing are made. S3 mounting and connection accessories; Align the two connecting steel bars, install a set of positioning rings and a set of wedges at the ends of the two connecting steel bars respectively, so that the ends of the connecting steel bars pass through the positioning ring holes and the heads of the wedges are inserted between the two connecting steel bars. The two connecting steel bars are positioned and connected by the positioning structure on opposite sides, so that the connecting steel bars, positioning rings and wedges together form a set of connecting accessories. S4 Pre-installation and positioning of precast pile connection structure; Remove the plastic protective cap inside the lower sleeve, pre-fit one end of multiple sets of connecting accessories with each lower sleeve of the precast pile, so that the wedge at the bottom of each set of connecting accessories and the end of the connecting steel rod are placed inside each lower sleeve, and the positioning ring is placed on the opening of each lower sleeve to form preliminary positioning. S5 Install the precast pile; remove the plastic protective cap inside the upper sleeve, hoist the upper precast pile above the lower precast pile, and align them vertically. Connect the other ends of multiple sets of connecting fittings to each upper sleeve of the upper precast pile, so that the wedges, positioning rings and the ends of the connecting steel bars at the top of each set of connecting fittings are aligned with the opening of the upper sleeve. By slowly lowering the upper precast pile, the two ends of the connecting steel bars are gradually pressed into the truncated cone-shaped chamber of the upper and lower sleeves by gravity settlement. Under the constraint of the two sets of positioning rings and wedges, the connecting steel bars are bent and deformed as a whole, and their outer side is squeezed and locked to the inner wall of the truncated cone-shaped chamber, thus realizing the connection between the upper and lower precast piles. The upper and lower precast piles of S6 are connected and secured; the driving of the upper precast piles continues. Under the strong downward pressure of the upper precast piles, the connection between the upper and lower precast piles will be further tightened, so that the sleeve, connecting steel bar and wedge are completely locked, and the upper and lower precast piles are completely and reliably connected.

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