Pre-stressed concrete precast pile with end plates and additional mechanical connection and construction method of pre-stressed concrete precast pile

Abstract

The invention discloses a pre-stressed concrete precast pile with an end plate and additional mechanical connection, which comprises a pre-stressed steel bar, a concrete pile body, the end plate and a mechanical connection assembly mounted on the end plate, and the mechanical connection assembly comprises an insertion rod, a bushing, a plurality of occlusion petals and a compression spring, a blind hole corresponding to the mechanical connecting assembly is formed in the end face of the concrete pile body, an opening of the blind hole communicates with the mounting hole, the lining is in threaded connection with the mounting hole, a plurality of occlusion petals are arranged in an inner space formed by the lining and the blind hole, and compression springs are arranged between the occlusion petals and the end face of an inner cavity of the blind hole. When the adjacent prestressed concrete precast piles with the end plates in additional mechanical connection are connected, the end plates provided with the inserting rods are close to the end plates provided with the bushings, the inserting sections penetrate through the bushings to be inserted into the occlusion petals, and then the end plates are welded. According to the prestressed concrete precast pile with the end plates and the additional mechanical connection, the pile head strength is guaranteed, and meanwhile the corrosion resistance and the connection strength of connection between piles are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of precast piles, and in particular to a precast precast pile of prestressed concrete with an end plate and an additional mechanical connection and a construction method thereof. Background Art

[0002] Precast concrete piles, with their advantages of high structural strength and efficient construction, are widely used in building foundations. Building pile foundation design requires a deep foundation depth to ensure superstructure stability. A single precast pile is often too long to reach the specified depth, necessitating the use of multiple piles connected end-to-end and driven down to the desired depth.

[0003] Concrete precast piles can be divided into two types according to the pile head structure: precast piles with end plates and precast piles without end plates. These two structures have their own advantages and disadvantages. The advantage of precast piles with end plates is that the pile heads are strong and not easy to break during construction, and the end plates disperse the stress at the joints, avoiding stress concentration. In addition, adjacent pile heads are connected by end plate welding, and the process is simple. However, the quality of end plate welding is greatly affected by the quality of workers, and welding has high requirements for the construction environment. Construction cannot be carried out in strong winds, heavy rain and other weather conditions, and the welds are easily corroded. Therefore, the corrosion resistance of piles with end plates is not high and cannot be used in corrosive environments. Summary of the Invention

[0004] In response to the shortcomings of the above-mentioned precast piles with end plates, the present invention proposes a precast prestressed concrete pile with end plates with additional mechanical connections. By arranging a mechanical connection structure on the end plate, the strength of the precast pile head is ensured while the corrosion resistance of the pile foundation is improved. Even if the weld on the outer side of the end plate is corroded, the mechanical connection structure can still ensure that the two sections of the pile are firmly connected together, thereby improving the safety of the pile foundation.

[0005] The present invention is achieved through the following technical solutions: A prestressed concrete precast pile with end plates and an additional mechanical connection, comprising prestressed steel bars, a concrete pile body, end plates, and a mechanical connection assembly mounted on the end plates, wherein the prestressed steel bars are arranged in the concrete pile body, and the end plates are arranged at both ends of the concrete pile body; The end plate is provided with a tensioning hole, which includes a mounting hole, an extrusion hole and a connecting hole. The inner wall of the mounting hole is provided with a thread. The inner wall of the extrusion hole is in the shape of a platform edge, and the inner diameter of the platform edge is larger on the outside and smaller on the inside. The connecting hole connects the mounting hole and the extrusion hole. The end of the prestressed steel bar is in the shape of a head and is fixed in the extrusion hole. The mechanical connection assembly includes an insertion rod, a bushing, a plurality of bite petals and a compression spring, and the end surface of the concrete pile body is provided with a blind hole corresponding to the mechanical connection assembly; The opening of the blind hole is communicated with the mounting hole, the bushing is threadedly connected to the mounting hole, a plurality of bite flaps are provided in the internal space formed by the bushing and the blind hole, and compression springs are provided between the bite flaps and the inner cavity end surface of the blind hole; The plurality of occlusal flaps are fitted together to form a hollow cylindrical structure having an outer cylindrical surface, the outer cylindrical surface is provided with a spiral groove, and a spiral spring is provided in the spiral groove; The insertion rod comprises an insertion section and a fixing section, and the insertion rod is threadedly connected to the mounting hole of the end plate of another additional mechanically connected prestressed concrete pile with an end plate through the fixing section; When connecting adjacent prestressed concrete precast piles with end plates with additional mechanical connections, the end plate on which the insertion rod is installed is moved closer to the end plate on which the bushing is installed, and the insertion section is inserted through the bushing into the bite flap before the end plate is welded.

[0006] As a further improvement of the present invention, the mechanical connection assembly also includes a sleeve, which is open at one end and is pre-buried in the blind hole. The opening of the sleeve is connected to the mounting hole. The multiple bite flaps are arranged in the internal space formed by the bushing and the sleeve, and the compression spring is arranged between the bite flap and the inner cavity end face of the sleeve.

[0007] As a further improvement of the present invention, the outer surface of the insertion section is provided with plug-in teeth, and the inner surface of the hollow column formed by the multiple occlusal petals is provided with occlusal tooth grooves corresponding to the plug-in teeth.

[0008] As a further improvement of the present invention, the concrete pile body is a solid pile body or a hollow pile body.

[0009] As a further improvement of the present invention, it further comprises an anchoring steel bar, one end of which is fixedly connected to the end plate, and the other end of which is inserted into the concrete pile body.

[0010] As a further improvement of the present invention, a threaded through hole is further provided on the end plate, the blind hole is arranged at a position corresponding to the threaded through hole, and the installation and connection of the mechanical connection assembly are completed through the threaded through hole.

[0011] As a further improvement of the present invention, a thickened area is provided on the end plate, and the tensioning hole and the threaded through hole are arranged on the thickened area.

[0012] The present invention also provides a construction method for precast prestressed concrete piles with end plates having additional mechanical connections, which uses the precast prestressed concrete piles with end plates having additional mechanical connections, and specifically comprises the following steps: S1: upsetting both ends of the prestressed steel bar, installing end plates at both ends of the prestressed steel bar, inserting the prestressed steel bar and its upsetting head from the installation hole, and then moving them to the extrusion hole through the connecting hole, and clamping the upsetting head of the prestressed steel bar by using the platform structure of the extrusion hole; S2: Place the prestressed steel bar and the end plate into the bottom formwork, pass the tension nut through the tension plate and screw it into the mounting hole. The screw portion of the tension nut includes a straight section and a threaded section. After the tension nut is installed, the straight section passes through the end plate, and the threaded section engages with the thread of the mounting hole. Before installing the tension nut, apply mold release oil to the straight section. S3: Pour unformed concrete into the bottom formwork, cover with the top formwork, and connect the bottom formwork and the top formwork with bolts. Connect the tensioning equipment for tensioning. After tensioning is completed, use the bottom formwork and the top formwork to lock the tensioning force, and remove the tensioning equipment. Lift the formwork and the pile body inside the formwork onto the centrifuge, centrifuge the concrete to form it, and then perform maintenance. After the concrete strength reaches the standard, the concrete pile body is formed, the prestressing is released, the top formwork and the bottom formwork are removed, and the tensioning nuts and tensioning plates are removed. After the tensioning nuts are removed, the blind hole is formed at the end of the concrete pile. After a period of rest, it is transported to the construction site; S4: constructing the first prestressed concrete precast pile with an end plate having an additional mechanical connection to a connection position at a preset position of the pile; S5: installing a compression spring and a plurality of bite petals in the blind hole in sequence, and then installing the bushing in the mounting hole of the end plate; S6: Installing the insertion rod in the installation hole of the end plate at one end of the second additional mechanically connected prestressed concrete precast pile with an end plate; S7: hoisting the second mechanically connected prestressed concrete pile with an end plate, with the plunger facing downward, to an area above the first mechanically connected prestressed concrete pile with an end plate; S8: lowering the second additional mechanically connected prestressed concrete precast pile with end plate and inserting the plunger into the blind hole of the first additional mechanically connected prestressed concrete precast pile with end plate to complete the mechanical connection; S9: Weld and fix the two end plates at the connection.

[0013] S10: Continue to construct the second prestressed concrete precast pile with an end plate with an additional mechanical connection, and repeat steps S4 to S9 until the pile foundation construction is completed.

[0014] As a further improvement of the present invention, a sleeve is added to the mechanical connection assembly, and the sleeve is pre-buried in the blind hole when manufacturing the concrete pile body to facilitate the removal of the tension nut. In this case, the construction method of the prestressed concrete precast pile with end plate with additional mechanical connection of the present invention specifically includes the following steps: S1: upsetting both ends of the prestressed steel bar, installing end plates at both ends of the prestressed steel bar, inserting the prestressed steel bar and its upsetting head from the installation hole, and then moving them to the extrusion hole through the connecting hole, and clamping the upsetting head of the prestressed steel bar by using the platform structure of the extrusion hole; S2: Place the prestressed steel bar and the end plate into the bottom formwork, pass the tension nut through the tension plate and screw it into the mounting hole, and the end of the tension nut passes through the end plate, and an internal thread corresponding to the tension nut is provided on the inner wall of the open end of the sleeve. After the tension nut passes through the end plate, it engages with the internal thread of the bushing, and the sleeve and the tension nut are threadedly connected on at least one side of the end plate so that the end surface of the sleeve is in close contact with the end plate; S3: Pour unformed concrete into the bottom formwork, cover with the top formwork, and connect the bottom formwork and the top formwork with bolts. Connect the tensioning equipment for tensioning. After tensioning is completed, use the bottom formwork and the top formwork to lock the tensioning force, and remove the tensioning equipment. Lift the formwork and the pile body inside the formwork onto the centrifuge, centrifuge the concrete to form it, and then perform curing. After the concrete strength reaches the standard, the concrete pile body is formed, the prestressing is released, the top formwork and the bottom formwork are removed, and the tensioning nuts and tensioning plates are removed. After a period of rest, it is transported to the construction site; S4: constructing the first mechanically connected prestressed concrete precast pile with an end plate to a connection position at a preset position of the pile, with the sleeve facing upward; S5: installing a compression spring and a plurality of bite petals in the sleeve in sequence, and then installing the bushing in the mounting hole of the end plate; S6: Installing the plunger in the mounting hole of the end plate of the second mechanically connected prestressed concrete pile with an end plate. If the sleeve is pre-buried at only one end of the second mechanically connected prestressed concrete pile with an end plate, the plunger should be installed at a different end from the sleeve. S7: hoisting the second mechanically connected prestressed concrete pile with an end plate, with the plunger facing downward, to an area above the first mechanically connected prestressed concrete pile with an end plate; S8: lowering the second additional mechanically connected prestressed concrete precast pile with end plate and inserting the plunger into the sleeve of the first additional mechanically connected prestressed concrete precast pile with end plate to complete the mechanical connection; S9: Weld and fix the two end plates at the connection.

[0015] S10: Continue to construct the second prestressed concrete precast pile with an end plate with an additional mechanical connection, and repeat steps S4 to S9 until the pile foundation construction is completed.

[0016] As a further improvement of the present invention, due to the presence of the connection hole, the thread on the inner wall of the mounting hole is incomplete, and the thread may be damaged due to uneven force during tensioning. Therefore, a threaded through hole is provided on the end plate to replace the mounting hole for installing the mechanical connection component. In this case, the construction method of the prestressed concrete precast pile with end plate with additional mechanical connection of the present invention specifically includes the following steps: S1: upsetting both ends of the prestressed steel bar, installing end plates at both ends of the prestressed steel bar, inserting the prestressed steel bar and its upsetting head from the installation hole, and then moving them to the extrusion hole through the connecting hole, and clamping the upsetting head of the prestressed steel bar by using the platform structure of the extrusion hole; S2: Place the prestressed steel bar and the end plate into the bottom formwork, pass the tensioning nut through the tensioning plate and screw it into the threaded through hole, and the end of the tensioning nut passes through the end plate, and an internal thread corresponding to the tensioning nut is provided on the inner wall of the open end of the sleeve. After the tensioning nut passes through the end plate, it engages with the internal thread of the bushing, and the sleeve and the tensioning nut are threadedly connected on at least one side of the end plate so that the end surface of the sleeve is in close contact with the end plate; S3: Pour unformed concrete into the bottom formwork, cover with the top formwork, and connect the bottom formwork and the top formwork with bolts. Connect the tensioning equipment for tensioning. After tensioning is completed, use the bottom formwork and the top formwork to lock the tensioning force, and remove the tensioning equipment. Lift the formwork and the pile body inside the formwork onto the centrifuge, centrifuge the concrete to form it, and then perform curing. After the concrete strength reaches the standard, the concrete pile body is formed, the prestressing is released, the top formwork and the bottom formwork are removed, and the tensioning nuts and tensioning plates are removed. After a period of rest, it is transported to the construction site; S4: constructing the first mechanically connected prestressed concrete precast pile with an end plate to a connection position at a preset position of the pile, with the sleeve facing upward; S5: installing a compression spring and a plurality of bite petals in the sleeve in sequence, and then installing the bushing in the threaded through hole of the end plate; S6: Install the insert rod in the threaded through hole of the end plate of the second prestressed concrete pile with an additional mechanical connection. If the sleeve is pre-buried at only one end of the second prestressed concrete pile with an additional mechanical connection, the insert rod and the sleeve must be installed at different ends. S7: hoisting the second mechanically connected prestressed concrete pile with an end plate, with the plunger facing downward, to an area above the first mechanically connected prestressed concrete pile with an end plate; S8: lowering the second additional mechanically connected prestressed concrete precast pile with end plate and inserting the plunger into the sleeve of the first additional mechanically connected prestressed concrete precast pile with end plate to complete the mechanical connection; S9: Weld and fix the two end plates at the connection.

[0017] S10: Continue to construct the second prestressed concrete precast pile with an end plate with an additional mechanical connection, and repeat steps S4 to S9 until the pile foundation construction is completed.

[0018] Compared with the prior art, the beneficial effects of the present invention are: the end plate protects the pile head of the concrete pile body, the mechanical connection assembly attached to the end plate improves the connection strength between the piles, and the mechanical connection structure, as another connection method besides end plate welding, improves the corrosion resistance of the prefabricated pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is an overall structural diagram of a prestressed concrete precast pile with an additional mechanical connection and an end plate according to the present invention; Figure 2 Schematic diagram of the end plate connection of the prestressed concrete precast pile with end plate with additional mechanical connection of the present invention; Figure 3 Schematic diagram of the precast pile connection method of the first embodiment of the prestressed concrete precast pile with end plates with additional mechanical connection of the present invention; Figure 4 1. An exploded view of a mechanical connection assembly of a prestressed concrete precast pile with an additional mechanical connection and an end plate according to the present invention; Figure 5 This is a structural diagram of the end plate of a first embodiment of a prestressed concrete precast pile with an additional mechanical connection and an end plate according to the present invention; Figure 6 Schematic diagram of the structure of the tensioning hole of the prestressed concrete precast pile with end plate with additional mechanical connection of the present invention; Figure 7 Schematic diagram of the connection mode of the mechanical connection assembly of the prestressed concrete precast pile with end plate with additional mechanical connection of the present invention; Figure 8 It is an assembly diagram of multiple occlusal petals of prestressed concrete precast piles with end plates with additional mechanical connections according to the present invention; Figure 9 Schematic diagram of the occlusal petal structure of the prestressed concrete precast pile with end plates with additional mechanical connection according to the present invention; Figure 10 Schematic diagram of the rod structure of the prestressed concrete precast pile with end plates with additional mechanical connection according to the present invention; Figure 11 Schematic diagram of the compression spring structure of the prestressed concrete precast pile with end plates with additional mechanical connection according to the present invention; Figure 12 Schematic diagram of the installation of tension nuts for a prestressed concrete pile with an additional mechanical connection and an end plate according to a first embodiment of the present invention; Figure 13 Schematic diagram of manufacturing a concrete pile body according to a first embodiment of a prestressed concrete precast pile with an additional mechanical connection and an end plate according to the present invention; Figure 14 2. It is a schematic diagram of the end plate structure of the second embodiment of the prestressed concrete precast pile with end plate with additional mechanical connection according to the present invention; Figure 15 Schematic diagram of the installation of tension nuts for a second embodiment of a prestressed concrete pile with an end plate having an additional mechanical connection according to the present invention; Figure 16 This is a schematic diagram of the tension nut structure and installation of a third embodiment of a prestressed concrete precast pile with an end plate and an additional mechanical connection according to the present invention; Figure 17 It is a schematic diagram of the connection mode of the mechanical connection assembly of the third embodiment of the invention of the prestressed concrete precast pile with end plates with additional mechanical connection. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions of various embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the new invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0022] The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0023] First embodiment A prestressed concrete precast pile with end plates and an additional mechanical connection includes a prestressed steel bar 1, a concrete pile body 2, an end plate 3, and a mechanical connection assembly installed on the end plate 3. The prestressed steel bar 1 is arranged in the concrete pile body 2, and the end plates 3 are arranged at both ends of the concrete pile body 2.

[0024] The end plate 3 is provided with circumferentially evenly distributed tensioning holes 4, which include mounting holes 5, extrusion holes 6 and connecting holes 7. The inner wall of the mounting hole 5 is provided with a thread, and the inner wall of the extrusion hole 6 is in the shape of a platform edge, and the inner diameter of the platform edge is larger on the outside and smaller on the inside. The connecting hole 7 connects the mounting hole 5 and the extrusion hole 6, and the end of the prestressed steel bar 1 is in the shape of a upset and fixed in the extrusion hole 6.

[0025] The mechanical connection assembly includes an insert rod 8, a bushing 9, four snap-fitting petals 10, a sleeve 11, and a compression spring 12. The end face of the concrete pile body is provided with a blind hole 26 corresponding to the mechanical connection assembly. The sleeve 11 is open at one end and is pre-buried in the blind hole 26. The opening of the sleeve 11 is connected to the mounting hole 5. The bushing 9 is threadedly connected to the mounting hole 5. The internal space formed by the bushing 9 and the sleeve 11 is provided with four snap-fitting petals 10. A compression spring 12 is provided between the snap-fitting petals 10 and the inner cavity end face of the sleeve 11. The two ends of the compression spring 12 are processed into a circular ring shape to make the end of the compression spring 12 more evenly stressed and less prone to slipping and bending during compression. The structure of the compression spring 12 is shown in the figure.

[0026] The four bite flaps 10 are fitted together to form a hollow cylindrical structure and have an outer cylindrical surface 13. The outer cylindrical surface 13 is provided with a spiral groove 14, and a spiral spring 15 is provided in the spiral groove 14; the spiral spring 15 is used to fit and connect the four bite flaps 10, on the one hand to prevent the four bite flaps 10 from being independent and scattered, and on the other hand to limit the mobility of the four bite flaps 10 along the central axis to avoid misalignment between the bite flaps 10. The spiral groove 14 is used to prevent the spiral spring 15 from sliding away from the four bite flaps 10, thereby ensuring the stability of the connection between the two and effectively improving the tightening effect of the four bite flaps 10.

[0027] In this embodiment, the pitch of the spiral groove 14 is designed to be equal to the pitch of the coil spring 15 in its natural state, thereby preventing the coil spring 15 from being in an axially compressed state for a long time, which would affect the life of the coil spring 15. The depth of the spiral groove 14 is greater than or equal to the cross-sectional diameter of the coil spring 15. The outer surface of the bite flap 10 corresponding to the end of the spiral groove 14 is spot-welded to the end of the coil spring 15. After one end of the coil spring 15 is welded to the bite flap 10, when the bite flap 10 separates, since one end of the coil spring 15 is fixed, the coil spring 15 will deform but will not separate from the spiral groove 14, nor will it move relative to the bite flap 10.

[0028] The insertion rod 8 includes an insertion section 16 and a fixing section 17. The insertion rod 8 is threadedly connected to the mounting hole 5 corresponding to the mounting position of the sleeve 11 of the end plate 3 of the prestressed concrete precast pile with an end plate, which is another additional mechanical connection, through the fixing section 17; When connecting adjacent prestressed concrete precast piles with end plates with additional mechanical connections, the end plate 3 with the inserted rod 8 is moved closer to the end plate 3 with the sleeve 9, so that the insertion section 16 passes through the sleeve 9, and the inserted rod 8 passes through the sleeve 9 and pushes the four bite petals 10. The bite petals 10 move with the insertion of the inserted rod 8 and squeeze the compression spring 12. At the same time, the four bite petals 10 separate, causing the enclosed hollow cylindrical space to become larger, making it easier to insert the inserted rod 8. After the inserted rod 8 is fully inserted, the four bite petals 10 move toward the sleeve 9 again under the joint action of the compression spring 12 and the coil spring 15 and tightly wrap the inserted rod 8. After the inserted rod 8 is inserted, the two end plates 3 fit together, and then the end plates 3 are welded and fixed.

[0029] The outer surface of the insertion section 16 is provided with inserting teeth 18, and the inner surface of the hollow column formed by the multiple engaging petals 10 is provided with engaging tooth grooves 19 corresponding to the inserting teeth 18. After the insertion rod 8 is inserted into the engaging petals 10, the inserting teeth 18 embed into the engaging tooth grooves 19, thereby enhancing the connection strength. Furthermore, an inserting chamfer 26 is provided at the base of the insertion section 16, and an inserting rim 27 corresponding to the inserting chamfer is provided at the opening of the bushing 9. After the insertion section is inserted, the inserting chamfer 26 embeds into the inserting rim 27, thereby enhancing the overall bending resistance of the insertion rod.

[0030] In this embodiment, the concrete pile body 2 is a hollow pile with a circular cross-section, the end plates 3 on both sides are circular rings, and the number of tensioning holes 4 is consistent with the number of prestressed steel bars 1 and is arranged circumferentially according to the setting form of the prestressed steel bars 1.

[0031] In other embodiments, the cross-section of the concrete pile body 2 may also be set to be square or other shapes.

[0032] In other embodiments, the concrete pile body 2 may also be configured as a solid pile body.

[0033] In other embodiments, the concrete pile body 2 may also be configured as a pile body with a variable cross-section along the pile extension direction.

[0034] In this embodiment, an anchoring steel bar 20 is also pre-embedded in the concrete pile body 2 . One end of the anchoring steel bar 20 is welded to the end plate 3 , and the other end is inserted into the concrete pile body 2 .

[0035] The end plate 3 is provided with a thickened area, and the tensioning hole 4 is arranged on the thickened area. In order to prevent the end plate 3 from being deformed or damaged during the tensioning process, the end plate 3 is thickened in a local area of ​​the tensioning hole 4.

[0036] The construction method of the prestressed concrete precast piles with end plates with additional mechanical connection of this embodiment comprises the following steps: S1: Both ends of the prestressed steel bar 1 are swaged, and end plates 3 are installed at both ends of the prestressed steel bar 1. The prestressed steel bar 1 and its swaged end are inserted from the installation hole 5 and then moved to the extrusion hole 6 through the connection hole 7. The ridge structure of the extrusion hole 6 is used to clamp the swaged end of the prestressed steel bar 1; S2: Place the prestressed steel bar 1 and the end plate 3 into the bottom template 24, pass the tensioning nut 21 through the tensioning plate 23 and screw it into the mounting hole 5, and the end of the tensioning nut 21 passes through the end plate 3, and an internal thread corresponding to the tensioning nut is provided on the inner wall of the open end of the sleeve 11, and the sleeve 11 is installed on the end of the tensioning nut 21 on at least one side of the end plate so that the end surface of the sleeve 11 is in close contact with the end plate 3 to prevent the concrete liquid from flowing into the sleeve 11 during pouring, and weld the anchor steel bar 20 on the inner side of the end plate 3; S3: Pour unformed concrete into the bottom formwork 24, cover it with the top formwork, and connect the bottom formwork 24 and the top formwork with bolts. Connect the tensioning device 22 for tensioning. After tensioning, use the bottom formwork 24 and the top formwork to lock the tensioning force, and remove the tensioning device 22. Lift the formwork and the pile body inside the formwork onto the centrifuge, centrifuge the concrete to form it, and then perform curing. After the concrete strength reaches the standard, the concrete pile body 2 is formed, the prestressing is released, and the top formwork and the bottom formwork 24 are removed. Then, the tensioning nut 21 and the tensioning plate 23 are removed. The pile body is transported to the construction site after resting for a period of time; S4: The first prestressed concrete precast pile with an additional mechanical connection and an end plate is constructed at a preset position of the pile to a connection position, with the sleeve 11 facing upward; S5: Install the compression spring 12 and the multiple bite flaps 10 in the sleeve 11 in sequence, and then install the bushing 9 in the mounting hole 5 of the end plate 3; S6: Install the rod 8 in the mounting hole 5 of the end plate 3 of the second additional mechanically connected prestressed concrete pile with an end plate. If the second additional mechanically connected prestressed concrete pile with an end plate 3 has only one end pre-buried with the sleeve 11, the rod 8 should be installed at a different end from the sleeve 11. S7: hoist the second mechanically connected prestressed concrete pile with end plate 3, keeping the plunger 8 facing downward, to the top of the first mechanically connected prestressed concrete pile with end plate 3; S8: Lowering the second additional mechanically connected prestressed concrete pile with end plate 3 so that the plunger 8 is inserted into the sleeve 11 of the first additional mechanically connected prestressed concrete pile with end plate 3 to complete the mechanical connection; S9: Weld and fix the two end plates 3 at the connection.

[0037] S10: Continue to construct the second prestressed concrete precast pile with an end plate with an additional mechanical connection, and repeat steps S4 to S9 until the pile foundation construction is completed.

[0038] Second embodiment: This embodiment differs from the first embodiment in that a threaded through-hole 25 is further provided on the end plate 3. The opening of the sleeve 11 communicates with the threaded through-hole 25, and the mechanical connection assembly is installed through the threaded through-hole 25. Because the connection hole 7 disrupts the integrity of the mounting hole 5, resulting in incomplete threads in the mounting hole 5, this can lead to uneven force during tensioning, making the end plate 3 susceptible to damage. Therefore, the additional threaded through-hole 25 with complete threads is provided on the end plate 3 for both tensioning and subsequent installation of the mechanical connection assembly.

[0039] In this embodiment, threaded through-holes 25 are positioned in the thickened area and are evenly distributed circumferentially. To ensure uniform stress on the prestressed steel bars 1, the pitch radius of the threaded through-holes 25 is equal to the pitch radius of the tensioning holes 4. When installing the mechanical connection assembly, the threaded through-holes 25 are used in place of the mounting holes 5. Therefore, the construction method of the prestressed concrete pile with end plates with additional mechanical connection in this embodiment specifically includes the following steps: S1: Both ends of the prestressed steel bar 1 are swaged, and end plates 3 are installed at both ends of the prestressed steel bar 1. The prestressed steel bar 1 and its swaged end are inserted from the installation hole 5 and then moved to the extrusion hole 6 through the connection hole 7. The ridge structure of the extrusion hole 6 is used to clamp the swaged end of the prestressed steel bar 1; S2: Place the prestressed steel bar 1 and the end plate 3 into the bottom template 24, pass the tensioning nut 21 through the tensioning plate 23 and screw it into the threaded through hole 25, and the end of the tensioning nut 21 passes through the end plate 3. Provide an internal thread corresponding to the tensioning nut on the inner wall of the open end of the sleeve 11, and install the sleeve 11 on the end of the tensioning nut 21 on at least one side of the end plate so that the end surface of the sleeve is in close contact with the end plate 3 to prevent concrete liquid from flowing into the sleeve 11 during pouring. Weld the anchor steel bar 20 on the inner side of the end plate 3; S3: Pour unformed concrete into the bottom formwork 24, cover it with the top formwork, and connect the bottom formwork 24 and the top formwork with bolts. Connect the tensioning device 22 for tensioning. After tensioning, use the bottom formwork 24 and the top formwork to lock the tensioning force, and remove the tensioning device 22. Lift the formwork and the pile body inside the formwork onto the centrifuge, centrifuge the concrete to form it, and then perform curing. After the concrete strength reaches the standard, the concrete pile body 2 is formed, the prestressing is released, and the top formwork and the bottom formwork 24 are removed. Then, the tensioning nut 21 and the tensioning plate 23 are removed. The pile body is transported to the construction site after resting for a period of time; S4: The first prestressed concrete precast pile with an additional mechanical connection and an end plate is constructed at a preset position of the pile to a connection position, with the sleeve 11 facing upward; S5: After sequentially installing the compression spring 12 and the plurality of bite flaps 10 in the sleeve 11 , the bushing 9 is installed in the threaded through hole 25 of the end plate 3 ; S6: Install the rod 8 in the threaded through hole 25 of the end plate 3 of the second additional mechanically connected prestressed concrete precast pile with an end plate. If the second additional mechanically connected prestressed concrete precast pile with an end plate 3 has only one end pre-buried with the sleeve 11, the rod 8 should be installed at a different end from the sleeve 11. S7: hoist the second mechanically connected prestressed concrete precast pile with end plate, keeping the plunger 8 facing downward, to the top of the first mechanically connected prestressed concrete precast pile with end plate 3; S8: Lowering the second additional mechanically connected prestressed concrete precast pile with end plate 8 and inserting it into the sleeve 11 of the first additional mechanically connected prestressed concrete precast pile with end plate to complete the mechanical connection; S9: Weld and fix the two end plates 3 at the connection.

[0040] S10: Continue to construct the second prestressed concrete precast pile with end plate 3 with additional mechanical connection, and repeat steps S4 to S9 until the pile foundation construction is completed.

[0041] Third embodiment This embodiment differs from the first embodiment in that the mechanical connection assembly does not include a sleeve 11. Instead, a blind hole 26 is formed on the end surface of the concrete pile body 2 during manufacture. Multiple snap-fitting petals 10 are positioned within the internal space formed by the bushing 9 and the blind hole 26, with compression springs 12 positioned between the snap-fitting petals 10 and the inner end surface of the blind hole 26. This solution omits the sleeve 11, reducing manufacturing costs. Therefore, the construction method of this embodiment of a prestressed concrete pile with an additional mechanical connection and end plate comprises the following steps: S1: Both ends of the prestressed steel bar 1 are swaged, and end plates 3 are installed at both ends of the prestressed steel bar 1. The prestressed steel bar 1 and its swaged end are inserted from the installation hole 5 and then moved to the extrusion hole 6 through the connection hole 7. The ridge structure of the extrusion hole 6 is used to clamp the swaged end of the prestressed steel bar 1; S2: Place the prestressed steel bar 1 and the end plate 3 into the bottom template 24, pass the tensioning nut 21 through the tensioning plate and screw it into the mounting hole 5. The screw portion of the tensioning nut 21 includes a straight section 27 and a threaded section 28. After the tensioning nut is installed, the straight section 27 passes through the end plate, and the threaded section 28 engages with the thread of the mounting hole 5. Before installation, apply mold release oil to the straight section of the tensioning nut 21 to facilitate subsequent removal. S3: Pour unformed concrete into the bottom formwork 24, cover it with the top formwork, and connect the bottom formwork 24 and the top formwork with bolts. Connect the tensioning device 22 for tensioning. After tensioning is completed, use the bottom formwork 24 and the top formwork to lock the tensioning force, and remove the tensioning device 22. Lift the formwork and the pile body inside the formwork onto the centrifuge, centrifuge the concrete to form it, and then perform maintenance. After the concrete strength reaches the standard, a concrete pile body is formed, and the prestressing is released. The top formwork and the bottom formwork are removed, and the tensioning nuts and tensioning plates are removed. After the tensioning nut 21 is removed, a blind hole 26 is formed at the end of the concrete pile body 2. The pile body is transported to the construction site after resting for a period of time; S4: constructing the first prestressed concrete precast pile with an end plate having an additional mechanical connection to a connection position at a preset position of the pile; S5: Install the compression spring 12 and the multiple bite flaps 10 in the blind hole 26 in sequence, and then install the bushing 9 in the mounting hole of the end plate; S6: Installing an insert rod 8 in the mounting hole of the end plate at one end of the second additional mechanically connected prestressed concrete precast pile with an end plate; S7: hoisting the second mechanically connected prestressed concrete pile with an end plate, with the plunger facing downward, to the top of the first mechanically connected prestressed concrete pile with an end plate; S8: Lowering the second additional mechanically connected prestressed concrete precast pile with end plate into the blind hole 26 of the first additional mechanically connected prestressed concrete precast pile with end plate to complete the mechanical connection; S9: Weld and fix the two end plates at the connection.

[0042] S10: Continue to construct the second prestressed concrete precast pile with an end plate with an additional mechanical connection, and repeat steps S4 to S9 until the pile foundation construction is completed.

[0043] Fourth embodiment The fourth embodiment differs from the third embodiment in that a threaded through hole 25 is further provided on the end plate 3, and the mechanical connection assembly is installed through the threaded through hole 25. Therefore, the construction method of the prestressed concrete precast pile with an additional mechanical connection and an end plate of this embodiment differs from the construction method of the third embodiment in the following aspects: S2: Place the prestressed steel bar 1 and the end plate 3 into the bottom template 24, pass the tensioning nut 21 through the tensioning plate and screw it into the threaded through hole 25. The screw portion of the tensioning nut 21 includes a straight section 27 and a threaded section 28. After the tensioning nut is installed, the straight section 27 passes through the end plate, and the threaded section 28 engages with the thread of the threaded through hole 25. Before installing the tensioning nut 21, apply mold release oil to the straight section 27 to facilitate subsequent removal. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A prestressed concrete precast pile with an end plate and an additional mechanical connection, comprising prestressed steel bars, a concrete pile body, an end plate, and a mechanical connection assembly mounted on the end plate, characterized in that: The prestressed steel bars are arranged in the concrete pile body, and the end plates are arranged at both ends of the concrete pile body; The end plate is provided with a tensioning hole, which includes a mounting hole, an extrusion hole and a connecting hole. The inner wall of the mounting hole is provided with a thread. The inner wall of the extrusion hole is in the shape of a platform edge, and the inner diameter of the platform edge is larger on the outside and smaller on the inside. The connecting hole connects the mounting hole and the extrusion hole. The end of the prestressed steel bar is in the shape of a head and is fixed in the extrusion hole. The mechanical connection assembly includes an insertion rod, a bushing, a plurality of bite petals and a compression spring, and the end surface of the concrete pile body has a blind hole corresponding to the mechanical connection assembly; The opening of the blind hole is communicated with the mounting hole, the bushing is threadedly connected to the mounting hole, a plurality of bite flaps are provided in the internal space formed by the bushing and the blind hole, and compression springs are provided between the bite flaps and the inner cavity end surface of the blind hole; The plurality of occlusal flaps are fitted together to form a hollow cylindrical structure having an outer cylindrical surface, the outer cylindrical surface is provided with a spiral groove, and a spiral spring is provided in the spiral groove; The insertion rod comprises an insertion section and a fixing section, and the insertion rod is threadedly connected to the mounting hole of the end plate of another additional mechanically connected prestressed concrete pile with an end plate through the fixing section; When connecting adjacent prestressed concrete precast piles with end plates with additional mechanical connections, the end plate on which the insertion rod is installed is moved closer to the end plate on which the bushing is installed, and the insertion section is inserted through the bushing into the bite flap before the end plate is welded.

2. The prestressed concrete precast pile with end plates having additional mechanical connections according to claim 1, characterized in that: The mechanical connection assembly also includes a sleeve, which is open at one end and is pre-buried in the blind hole. The opening of the sleeve is connected to the mounting hole. The multiple bite flaps are arranged in the internal space formed by the bushing and the sleeve, and the compression spring is arranged between the bite flap and the inner cavity end face of the sleeve.

3. The prestressed concrete precast pile with end plates having additional mechanical connections according to claim 1, characterized in that: The outer surface of the insertion section is provided with plug-in teeth, and the inner surface of the hollow column formed by the multiple occlusal petals is provided with occlusal tooth grooves corresponding to the plug-in teeth.

4. The prestressed concrete precast pile with end plates having additional mechanical connections according to claim 1, characterized in that: The concrete pile body is a solid pile body or a hollow pile body.

5. The prestressed concrete precast pile with end plates having additional mechanical connections according to claim 1, characterized in that: It also includes an anchoring steel bar, one end of which is fixedly connected to the end plate, and the other end of which is inserted into the concrete pile body.

6. The prestressed concrete precast pile with end plates having additional mechanical connections according to any one of claims 1 to 5, characterized in that: The end plate is further provided with a threaded through hole, the blind hole is arranged at a position corresponding to the threaded through hole, and the installation and connection of the mechanical connection assembly are completed through the threaded through hole.

7. The prestressed concrete precast pile with end plates having additional mechanical connections according to claim 6, characterized in that: A thickened area is provided on the end plate, and the tensioning hole and the threaded through hole are provided on the thickened area.

8. A construction method for precast prestressed concrete piles with end plates and additional mechanical connections, characterized by: The method of using the prestressed concrete precast pile with end plates with additional mechanical connection according to claim 1 specifically comprises the following steps: S1: upsetting both ends of the prestressed steel bar, installing end plates at both ends of the prestressed steel bar, inserting the prestressed steel bar and its upsetting head from the installation hole, and then moving them to the extrusion hole through the connecting hole, and clamping the upsetting head of the prestressed steel bar by using the platform structure of the extrusion hole; S2: Place the prestressed steel bar and the end plate into the bottom formwork, pass the tension nut through the tension plate and screw it into the mounting hole. The screw portion of the tension nut includes a straight section and a threaded section. After the tension nut is installed, the straight section passes through the end plate, and the threaded section engages with the thread of the mounting hole. Before installing the tension nut, apply mold release oil to the straight section. S3: pouring unformed concrete into the bottom formwork, covering it with a top formwork, and connecting the bottom formwork and the top formwork with bolts, connecting the tensioning equipment for tensioning, locking the tensioning force by using the bottom formwork and the top formwork after tensioning, removing the tensioning equipment, hanging the formwork and the pile body in the formwork on a centrifuge, centrifugally forming the concrete, and then curing it. After the concrete strength reaches the standard, the concrete pile body is formed, the prestressing is released, the top formwork and the bottom formwork are removed, and the tensioning nuts and tensioning plates are removed. After the tensioning nuts are removed, the blind hole is formed at the end of the concrete pile. After a period of rest, the concrete pile is transported to the construction site. S4: constructing the first prestressed concrete precast pile with an end plate having an additional mechanical connection to a connection position at a preset position of the pile; S5: installing a compression spring and a plurality of bite petals in the blind hole in sequence, and then installing the bushing in the mounting hole of the end plate; S6: Installing the insertion rod in the installation hole of the end plate at one end of the second additional mechanically connected prestressed concrete precast pile with an end plate; S7: hoisting the second mechanically connected prestressed concrete pile with an end plate, with the plunger facing downward, to an area above the first mechanically connected prestressed concrete pile with an end plate; S8: lowering the second additional mechanically connected prestressed concrete precast pile with end plate and inserting the plunger into the blind hole of the first additional mechanically connected prestressed concrete precast pile with end plate to complete the mechanical connection; S9: Weld and fix the two end plates at the connection; S10: Continue to construct the second prestressed concrete precast pile with an end plate with an additional mechanical connection, and repeat steps S4 to S9 until the pile foundation construction is completed.

9. A construction method for prestressed concrete precast piles with end plates and additional mechanical connections, characterized by: The method of using the prestressed concrete precast pile with end plates with additional mechanical connection as claimed in claim 2 specifically comprises the following steps: S1: upsetting both ends of the prestressed steel bar, installing end plates at both ends of the prestressed steel bar, inserting the prestressed steel bar and its upsetting head from the installation hole, and then moving them to the extrusion hole through the connecting hole, and clamping the upsetting head of the prestressed steel bar by using the platform structure of the extrusion hole; S2: Place the prestressed steel bar and the end plate into the bottom formwork, pass the tension nut through the tension plate and screw it into the mounting hole, and the end of the tension nut passes through the end plate, and an internal thread corresponding to the tension nut is provided on the inner wall of the open end of the sleeve. After the tension nut passes through the end plate, it engages with the internal thread of the bushing, and the sleeve and the tension nut are threadedly connected on at least one side of the end plate so that the end surface of the sleeve is in close contact with the end plate; S3: pouring unformed concrete into the bottom formwork, covering it with the top formwork, and connecting the bottom formwork and the top formwork with bolts, connecting the tensioning equipment for tensioning, locking the tensioning force with the bottom formwork and the top formwork after tensioning, removing the tensioning equipment, and hoisting the formwork and the pile body in the formwork onto a centrifuge to centrifuge concrete to form it, and then curing it. After the concrete strength reaches the standard, the concrete pile body is formed, and the prestressing is released. The top formwork and the bottom formwork are removed, and the tensioning nuts and tensioning plates are removed. After a period of rest, the concrete is transported to the construction site; S4: constructing the first mechanically connected prestressed concrete precast pile with an end plate to a connection position at a preset position of the pile, with the sleeve facing upward; S5: installing a compression spring and a plurality of bite petals in the sleeve in sequence, and then installing the bushing in the mounting hole of the end plate; S6: Installing the plunger in the mounting hole of the end plate of the second mechanically connected prestressed concrete pile with an end plate. If the sleeve is pre-buried at only one end of the second mechanically connected prestressed concrete pile with an end plate, the plunger should be installed at a different end from the sleeve. S7: hoisting the second mechanically connected prestressed concrete pile with an end plate, with the plunger facing downward, to an area above the first mechanically connected prestressed concrete pile with an end plate; S8: lowering the second additional mechanically connected prestressed concrete precast pile with end plate and inserting the plunger into the sleeve of the first additional mechanically connected prestressed concrete precast pile with end plate to complete the mechanical connection; S9: Weld and fix the two end plates at the connection; S10: Continue to construct the second prestressed concrete precast pile with an end plate with an additional mechanical connection, and repeat steps S4 to S9 until the pile foundation construction is completed.

10. A construction method for prestressed concrete precast piles with end plates and additional mechanical connections, characterized by: The method of using the prestressed concrete precast pile with end plates with additional mechanical connection according to claim 6 specifically comprises the following steps: S1: upsetting both ends of the prestressed steel bar, installing end plates at both ends of the prestressed steel bar, inserting the prestressed steel bar and its upsetting head from the installation hole, and then moving them to the extrusion hole through the connecting hole, and clamping the upsetting head of the prestressed steel bar by using the platform structure of the extrusion hole; S2: Place the prestressed steel bar and the end plate into the bottom formwork, pass the tensioning nut through the tensioning plate and screw it into the threaded through hole, and the end of the tensioning nut passes through the end plate, and an internal thread corresponding to the tensioning nut is provided on the inner wall of the open end of the sleeve. After the tensioning nut passes through the end plate, it engages with the internal thread of the bushing, and the sleeve and the tensioning nut are threadedly connected on at least one side of the end plate so that the end surface of the sleeve is in close contact with the end plate; S3: pouring unformed concrete into the bottom formwork, covering it with the top formwork, and connecting the bottom formwork and the top formwork with bolts, connecting the tensioning equipment for tensioning, locking the tensioning force with the bottom formwork and the top formwork after tensioning, removing the tensioning equipment, and hoisting the formwork and the pile body in the formwork onto a centrifuge to centrifuge concrete to form it, and then curing it. After the concrete strength reaches the standard, the concrete pile body is formed, and the prestressing is released. The top formwork and the bottom formwork are removed, and the tensioning nuts and tensioning plates are removed. After a period of rest, the concrete is transported to the construction site; S4: constructing the first mechanically connected prestressed concrete precast pile with an end plate to a connection position at a preset position of the pile, with the sleeve facing upward; S5: installing a compression spring and a plurality of bite petals in the sleeve in sequence, and then installing the bushing in the threaded through hole of the end plate; S6: Install the insert rod in the threaded through hole of the end plate of the second prestressed concrete pile with an additional mechanical connection. If the sleeve is pre-buried at only one end of the second prestressed concrete pile with an additional mechanical connection, the insert rod and the sleeve must be installed at different ends. S7: hoisting the second mechanically connected prestressed concrete pile with an end plate, with the plunger facing downward, to an area above the first mechanically connected prestressed concrete pile with an end plate; S8: lowering the second additional mechanically connected prestressed concrete precast pile with end plate and inserting the plunger into the sleeve of the first additional mechanically connected prestressed concrete precast pile with end plate to complete the mechanical connection; S9: Weld and fix the two end plates at the connection; S10: Continue to construct the second prestressed concrete precast pile with an end plate with an additional mechanical connection, and repeat steps S4 to S9 until the pile foundation construction is completed.

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