PHC pile with conical integrated concrete pile tip and construction method of PHC pile

Abstract

The invention relates to the technical field of PHC pile construction, in particular to a PHC pile with a conical integrated concrete pile tip and a construction method thereof.The PHC pile with the conical integrated concrete pile tip comprises a PHC pipe pile and the concrete pile tip fixed to the bottom of the PHC pipe pile, and a pile core reinforcement cage is placed at the position, close to the top end, in the PHC pipe pile; micro-expansion concrete is poured in the PHC pipe pile and located at the position of the pile core reinforcement cage. The PHC pile with the concrete conical integrated pile tip further comprises a bearing assembly arranged in the PHC pipe pile. The bearing assembly is additionally arranged in the PHC pipe pile, on one hand, the bearing effect on the pile core reinforcement cage is achieved, on the other hand, the bearing assembly is matched with the reinforcing assembly of the pile core reinforcement cage to increase the extrusion force between the pile core reinforcement cage and the PHC pipe pile, and then the stability and firmness of placement of the pile core reinforcement cage are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of PHC pile construction, and specifically relates to a PHC pile with a concrete conical integrated pile tip and a construction method thereof. Background Art

[0002] PHC pipe piles, that is, prestressed high-strength concrete pipe piles, are a kind of hollow cylindrical concrete precast components made by the pre-tensioned centrifugal forming process and steam cured at about 180°C under 10 atmospheric pressures. PHC pipe piles are applicable to geological conditions such as general cohesive soil, sandy soil, and strongly weathered soil, especially suitable for soft soil foundations. For hard soil, a pile tip needs to be added at the bottom of the PHC pipe pile to better break the soil; it is also widely used in various building engineering foundations such as high-rise, multi-story buildings, large-span structures, industrial factories, etc., as well as special projects such as nuclear power plants, oil tank foundations, high-rise towers, etc.

[0003] After the PHC pipe pile is pressed into the ground, concrete needs to be poured into it to increase the support strength of the PHC pipe pile. Before pouring the slightly expanding concrete, a pile core steel cage needs to be placed into the PHC pipe pile. At present, the steel cage is only fixed to the PHC pipe pile by friction. When pouring the slightly expanding concrete, the weight of the slightly expanding concrete acts on the supporting plate of the pile core steel cage. Before it solidifies, there is a severe test on the bearing capacity of the pile core steel cage. The firmness and stability between the pile core steel cage and the pipe pile need to be improved. Therefore, the present invention provides a PHC pile with a concrete conical integrated pile tip and a construction method thereof. Summary of the Invention

[0004] The present invention provides a PHC pile with a concrete conical integrated pile tip and a construction method thereof to solve the problem that the stability and firmness of the pile core steel cage placed in the PHC pipe pile in the related technology need to be improved.

[0005] The present invention provides a PHC pile with a concrete conical integrated pile tip, including a PHC pipe pile and a concrete pile tip fixed at the bottom of the PHC pipe pile. A pile core steel cage is placed near the top inside the PHC pipe pile. The pile core steel cage includes a plurality of second main steel bars and second stirrups welded outside the second main steel bars. A supporting plate is fixed at the bottom of the plurality of second main steel bars. Micro-expanding concrete is poured inside the PHC pipe pile at the position of the pile core steel cage. The PHC pile with a concrete conical integrated pile tip further includes a load-bearing component arranged inside the PHC pipe pile. At least two load-bearing components are distributed up and down. The load-bearing component includes a plurality of metal installation pipes and a supporting member fixedly connected to the metal installation pipe. One end of the metal installation pipe close to the axis of the PHC pipe pile is flush with the inner wall of the PHC pipe pile, and this end is open.

[0006] The supporting member includes a round rod disposed inside the metal installation pipe and a rectangular plate fixed to the end of the round rod. A circular through-hole is provided on the rectangular plate, and a reinforcing steel bar penetrates through the supporting members that are directly opposite to each other vertically. A sealing plate for supporting the reinforcing steel bar is fixed to the bottom end of the PHC pipe pile.

[0007] Positioning holes corresponding to the reinforcing steel bars one by one are provided on the upper surface of the supporting plate near the edge. The supporting plate is placed on a plurality of supporting members, and the reinforcing steel bars penetrate through the corresponding positioning holes. The pile core steel cage further includes reinforcing components corresponding to the reinforcing steel bars one by one.

[0008] The lowering of the pile core steel cage is completed by a placing device, and before pouring the slightly expanded concrete, the placing device is removed from the PHC pipe pile.

[0009] In a possible implementation manner, the PHC pipe pile includes a steel cage and a concrete pipe pile cast outside the steel cage and solidified. The steel cage includes a plurality of first main steel bars distributed in a circumferential manner, first stirrups welded outside the first main steel bars, and reinforcing ribs welded inside the first main steel bars. A plurality of the first stirrups and reinforcing ribs are distributed from top to bottom. Metal rings are provided at both ends of the concrete pipe pile and the large-diameter end of the concrete pile tip. A plurality of mounting holes are provided on the metal rings in a circumferential distribution. Bolts are jointly provided in the corresponding mounting holes on the PHC pipe pile and the concrete pile tip, and the metal ring on the PHC pipe pile is welded and fixed to the metal ring on the concrete pile tip.

[0010] In a possible implementation manner, during the pile pressing process, when the height of a single PHC pipe pile is insufficient, pile splicing is required. The fixing method of pile splicing is the same as the fixing method of the PHC pipe pile and the concrete pile tip. The load-bearing component is located in the uppermost PHC pipe pile. The metal installation pipe is fixed to the first main steel bar by welding, and a plurality of metal installation pipes all point to the axis of the PHC pipe pile.

[0011] In a possible implementation manner, the reinforcing component includes an L-shaped mounting frame fixed outside the second main steel bar. A groove is provided at the top end of the vertical section of the L-shaped mounting frame, and a rotating plate is rotatably provided in the groove. A counterweight block is further fixed to one end of the rotating plate close to the inner wall of the PHC pipe pile. The rotating plate is in an inclined state under the action of the lever principle, and the projected length of the inclined rotating plate on the horizontal plane is less than the distance between the second main steel bar and the inner wall of the PHC pipe pile.

[0012] In a possible implementation manner, during the downward movement of the rotating plate, an upward pushing force from the reinforcing steel bar is received, causing the rotating plate to gradually rotate towards the horizontal state. Anti-slip layers are provided at both ends of the rotating plate. When the rotating plate approaches the horizontal state, both ends of the rotating plate are in close contact with the outer wall of the second main steel bar and the inner wall of the PHC pipe pile respectively. At this time, the supporting plate is placed on the supporting member.

[0013] In a possible implementation manner, the placing device includes a rotating disk, the top end of the rotating disk is rotatably connected to an external lifting device, the bottom end of the rotating disk is fixedly connected with an installation cylinder, the installation cylinder is a cylindrical structure with an open bottom, a fixing bracket is fixed at the middle position inside the installation cylinder, synchronous moving components are arranged at both the upper and lower ends of the fixing bracket, and the upper and lower synchronous moving components are symmetrically distributed. The placing device further includes a bending part for bending the second main reinforcement and a reinforcing bar clamping part for restricting the bent part of the second main reinforcement. The upper synchronous moving component is used to push the bending part, and the lower synchronous moving component is used to push the reinforcing bar clamping part. Both the reinforcing bar clamping part and the bending part are multiple and are evenly distributed in a circumferential manner, and the reinforcing bar clamping part corresponds to the bending part one by one.

[0014] In a possible implementation manner, the fixing bracket is composed of a circular ring and a support rod installed between the outer wall of the circular ring and the inner wall of the installation cylinder. The lower synchronous moving component includes a cylinder fixedly installed at the circular ring, the bottom end of the telescopic section of the cylinder is fixedly installed with a fixed circular plate, and a rotating ring is rotatably connected to the outer circumference of the fixed circular plate. The synchronous moving component further includes vertical plates arranged inside the installation cylinder and distributed in a circumferential manner. Two parallel hinge rods are arranged between the rotating ring and each vertical plate, and the two ends of the hinge rod are respectively hinged to the rotating ring and the vertical plate.

[0015] In a possible implementation manner, the reinforcing bar clamping part includes two L-shaped telescopic rods arranged vertically and sliding through the side wall of the installation cylinder, and the L-shaped telescopic rods are fixedly connected to the lower synchronous moving component.

[0016] The bending part includes a push block sliding through the side wall of the installation cylinder, and the push block is fixedly connected to the upper synchronous moving component. A sliding groove is opened at one end of the push block extending out of the installation cylinder, and a spring is fixedly connected to the bottom of the sliding groove. The bending part further includes a push plate, where the push plate is composed of a T-shaped slider slidably arranged in the sliding groove and an arc-shaped push plate fixed to the outer wall of the T-shaped slider. The concave surface of the arc-shaped push plate abuts against the outer end of the push block, and the bottom of the arc-shaped push plate is lower than the bottom of the push block.

[0017] The present invention also provides a construction method for a PHC pile of a concrete conical integrated pile tip, including the following steps: S1. Pile tip fixing: Fix a concrete pile tip at the bottom of the PHC pipe pile, apply an anti-rust layer on the outer surface of the connection between the PHC pipe pile and the concrete pile tip, and apply an asphalt anti-corrosion layer on the outer surface of the PHC pipe pile.

[0018] S2. Pile sinking: Use a pile driver to press the PHC pipe pile with the concrete pile tip into the soil.

[0019] S3. Pile splicing: Stop pile pressing at a position 1 meter above the ground on the top of the lower PHC pipe pile, fix the upper PHC pipe pile, and then continue pile sinking.

[0020] S4. Pile driving: When the pile top is close to the design elevation, use a pile driver to drive the pile to the design elevation.

[0021] S5. Core filling concrete: Lower the pile core steel cage into the PHC pipe pile through a placing device so that there is a tight contact between the PHC pipe pile and the pile core steel cage. Then bend the No. 2 main reinforcement and press it on the top of the PHC pipe pile, and then pour slightly expanding concrete into the position of the pile core steel cage.

[0022] S6. Pile cutting: After the slightly expanding concrete solidifies, chisel off the over-poured part.

[0023] S7. Testing: Conduct pile integrity testing and single-pile vertical bearing capacity testing on the pile foundation after pile cutting.

[0024] One or more of the above technical solutions in the embodiments of the present invention have at least one of the following technical effects: 1. By adding a load-bearing component inside the PHC pipe pile, on the one hand, it plays a role in supporting the pile core steel cage, and on the other hand, it cooperates with the reinforcement component of the pile core steel cage to increase the extrusion force between the pile core steel cage and the PHC pipe pile, increasing the stability and firmness of the placement of the pile core steel cage.

[0025] 2. By using the placing device to lower the pile core steel cage, it can not only limit the bent part of the No. 2 main reinforcement to prevent the No. 2 main reinforcement from detaching from the No. 2 stirrup, but also uniformly bend and press the No. 2 main reinforcement, improving the bending efficiency and reducing the manual participation. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the concrete pile tip starting to be pressed into the ground with the first PHC pipe pile.

[0027] Figure 2 It is a schematic diagram after the PHC pipe pile is spliced.

[0028] Figure 3 It is a schematic diagram after installing the load-bearing component in the uppermost PHC pipe pile.

[0029] Figure 4 It is a schematic diagram of the pile core steel cage ready to be placed in the uppermost PHC pipe pile.

[0030] Figure 5 It is a schematic diagram of the pile core steel cage entering the uppermost PHC pipe pile.

[0031] Figure 6 It is a schematic diagram of the state where the pile core steel cage is placed.

[0032] Figure 7 It is a schematic diagram of the bending of the second main reinforcement bar of the steel cage in the pile core.

[0033] Figure 8 It is a schematic diagram after micro-expansion concrete is poured into the uppermost PHC pipe pile.

[0034] Figure 9 It is a schematic diagram of the partial structure of the load-bearing component and the PHC pipe pile.

[0035] Figure 10 It is a three-dimensional structure schematic diagram of the steel cage in the pile core.

[0036] Figure 11 It is a schematic diagram of the partial structure of the placing device for fixing the steel cage in the pile core.

[0037] Figure 12 It is Figure 11 The three-dimensional structure schematic diagram after sectioning.

[0038] Figure 13 It is a three-dimensional structure schematic diagram of the placing device.

[0039] Figure 14 It is a three-dimensional structure schematic diagram of the supporting member and the reinforcing steel bar.

[0040] In the figure: 1. PHC pipe pile; 11. First main reinforcement bar; 12. First stirrup; 13. Reinforcing bar; 14. Concrete pipe pile; 15. Metal ring; 16. Bolt; 17. Sealing plate; 2. Load-bearing component; 21. Metal installation pipe; 22. Supporting member; 23. Reinforcing steel bar; 3. Concrete pile tip; 4. Steel cage in the pile core; 41. Second main reinforcement bar; 42. Second stirrup; 43. Support plate; 431. Positioning hole; 44. Reinforcing component; 441. L-shaped installation frame; 442. Rotating plate; 443. Counterweight; 5. Placing device; 51. Rotating disk; 52. Installation cylinder; 53. Fixed support; 54. Cylinder; 55. Fixed circular plate; 56. Rotating ring; 57. Hinge rod; 58. Vertical plate; 59. Reinforcing bar clamping part; 591. L-shaped telescopic rod; 50. Bending part; 501. Pushing block; 502. Sliding groove; 503. Pushing plate; 504. Spring; 6. Micro-expansion concrete. Detailed implementation manners

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described below, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific implementation manners disclosed below.

[0042] Please refer to Figure 1 、 Figure 2 and Figure 3 , a PHC pile with an integrated concrete conical pile tip, comprising a PHC pipe pile 1 and a concrete pile tip 3 fixed to the bottom of the PHC pipe pile 1. The PHC pipe pile 1 includes a steel reinforcement cage and a concrete pipe pile 14 cast outside the steel reinforcement cage and solidified. The steel reinforcement cage includes a plurality of first main reinforcements 11 distributed in a circumferential manner, first stirrups 12 welded outside the first main reinforcements 11, and reinforcing ribs 13 welded inside the first main reinforcements 11. The first stirrups 12 and the reinforcing ribs 13 are each provided with a plurality of them from top to bottom, and the number of the reinforcing ribs 13 is less than the number of the first stirrups 12. Metal rings 15 are provided at both ends of the concrete pipe pile 14 and the large-diameter end of the concrete pile tip 3. A plurality of mounting holes are provided in a circumferential distribution on the metal rings 15. When fixing the concrete pile tip 3 and the PHC pipe pile 1 together, bolts 16 need to be fixed to the mounting holes at the bottom of the PHC pipe pile 1 first, and then the mounting holes on the concrete pile tip 3 are docked with the corresponding bolts 16, and then the metal rings 15 on the PHC pipe pile 1 and the metal rings 15 on the concrete pile tip 3 are welded and fixed by welding to form a PHC pile with an integrated pile tip.

[0043] It should be noted that during actual pile pressing, if the height of a single PHC pipe pile 1 is insufficient, pile splicing is required, and the fixing method of pile splicing is the same as the fixing method of the PHC pipe pile 1 and the concrete pile tip 3.

[0044] Please refer to Figure 2 、 Figure 3 、 Figure 9 and Figure 14 , a load-bearing assembly 2 is provided inside the uppermost PHC pipe pile 1. At least two load-bearing assemblies 2 are provided, and the two load-bearing assemblies 2 are distributed vertically. The load-bearing assembly 2 includes a plurality of metal mounting pipes 21 and a supporting member 22 fixedly connected to the metal mounting pipes 21. The metal mounting pipes 21 are fixed to the first main reinforcements 11, and a plurality of metal mounting pipes 21 all point to the axis of the PHC pipe pile 1. The end of the metal mounting pipe 21 away from the first main reinforcement 11 is flush with the inner wall of the concrete pipe pile 14. The inner wall of the PHC pipe pile 1 is open at the position corresponding to the metal mounting pipe 21. The supporting member 22 includes a round rod inserted into the metal mounting pipe 21 and a rectangular plate fixed to the end of the round rod. A circular through hole is provided on the rectangular plate. The supporting members 22 in the upper and lower two load-bearing assemblies 2 are directly opposite to each other, and the circular through holes on the directly opposite supporting members 22 are directly opposite to each other; a sealing plate 17 is further provided at the top of the PHC pipe pile 1 adjacent to the uppermost PHC pipe pile 1, and the circumferential surface of the sealing plate 17 is fixed to the inner wall of the metal ring 15; a reinforcing steel bar 23 is commonly penetrated through the directly opposite supporting members 22 up and down, and the bottom end of the reinforcing steel bar 23 is in contact with the top of the sealing plate 17.

[0045] It should be noted that the metal installation pipe 21 is fixed to the first main reinforcement bar 11 by welding. In actual applications, multiple metal installation pipes 21 can be welded to the corresponding first main reinforcement bars 11 at intervals, or metal installation pipes 21 can be welded to each first main reinforcement bar 11; the surface of the round rod on the supporting member 22 can be a rough surface to increase the friction when inserted into the metal installation pipe 21, or it can be a threaded groove and fixed in the metal installation pipe 21 by means of threaded connection to ensure that the rectangular plate is in a horizontal state. The process of inserting the reinforcement bar 23 into the supporting member 22 is manually operated. The circumferentially distributed metal installation pipes 21 provide an installation foundation for the supporting member 22. On the one hand, the circumferentially distributed supporting members 22 can provide a supporting force for the pile core steel reinforcement cage 4 extending into the PHC pipe pile 1 later, and on the other hand, the load-bearing assembly 2 can also increase the friction between the PHC pipe pile 1 and the pile core steel reinforcement cage 4.

[0046] Please refer to Figure 4 、 Figure 5 、 Figure 6 、 Figure 8 and Figure 10 , the pile core steel reinforcement cage 4 is placed in the uppermost PHC pipe pile 1. The pile core steel reinforcement cage 4 includes a number of circumferentially distributed second main reinforcement bars 41 and second stirrups 42 welded to the outside of the second main reinforcement bars 41. A number of second stirrups 42 are arranged from top to bottom. The bottoms of a number of second main reinforcement bars 41 are jointly fixed with a support plate 43. Positioning holes 431 are formed at positions near the edge of the upper surface of the support plate 43, and the positioning holes 431 correspond to the reinforcement bars 23 one by one. The support plate 43 is placed on a number of supporting members 22, and the reinforcement bars 23 pass through the corresponding positioning holes 431; the pile core steel reinforcement cage 4 further includes a reinforcement assembly 44 corresponding to the reinforcement bars 23 one by one. The reinforcement assembly 44 includes an L-shaped mounting frame 441 fixed to the outside of the second main reinforcement bar 41. A groove is formed at the top of the vertical section of the L-shaped mounting frame 441, and a rotating plate 442 is rotatably arranged in the groove. A counterweight 443 is further fixed to one end of the rotating plate 442 close to the inner wall of the PHC pipe pile 1. The rotating plate 442 is in an inclined state under the action of the lever principle, and the projected length of the inclined rotating plate 442 on the horizontal plane is less than the distance between the second main reinforcement bar 41 and the inner wall of the PHC pipe pile 1, ensuring that the rotating plate 442 does not hinder the descending process during the downward placement of the pile core steel reinforcement cage 4.

[0047] Please refer to Figure 10 and Figure 11, It should be noted that in order to enhance the connection firmness between the L-shaped mounting bracket 441 and the second main reinforcement bar 41, the end of the horizontal section of the L-shaped mounting bracket 441 can be welded at the contact position between the second main reinforcement bar 41 and the second stirrup 42. During the process of gradually placing the pile core steel reinforcement cage 4 into the PHC pipe pile 1, the reinforcement bar 23 will first penetrate through the corresponding positioning hole 431, and then the reinforcement assembly 44 will gradually approach the top of the reinforcement bar 23. When the bottom end of the rotating plate 442 contacts the reinforcement bar 23, the rotating plate 442 will be subjected to an upward pushing force from the reinforcement bar 23, causing the rotating plate 442 to gradually rotate towards the horizontal state. Both ends of the rotating plate 442 are anti-slip layers with a large coefficient of friction. When the rotating plate 442 approaches the horizontal state, the two ends of the rotating plate 442 are in close contact with the outer wall of the second main reinforcement bar 41 and the inner wall of the PHC pipe pile 1 respectively. At this time, the support plate 43 has also been placed on the support member 22. Through the support of the support member 22 for the support plate 43, not only the stability of the pile core steel reinforcement cage 4 inside the PHC pipe pile 1 is improved, but also the extrusion force between the pile core steel reinforcement cage 4 and the PHC pipe pile 1 can be further increased by the support between the second main reinforcement bar 41 and the PHC pipe pile 1 through the rotating plate 442. Compared with the traditional method that only relies on the friction between the support plate 43 and the inner wall of the PHC pipe pile 1 and the friction between the bent second main reinforcement bar 41 and the top of the PHC pipe pile 1, the placement of the pile core steel reinforcement cage 4 is more stable.

[0048] Please refer to Figure 8 , micro-expansion concrete 6 is poured inside the PHC pipe pile 1 and on top of the support plate 43.

[0049] Please refer to Figure 5 , Figure 7 , Figure 11 , Figure 12 and Figure 13, the lowering process of the pile core steel reinforcement cage 4 is completed by a placement device 5. The placement device 5 includes a rotating disc 51. The top end of the rotating disc 51 is rotatably connected to an external lifting device (such as a cylinder or a hydraulic cylinder). The bottom end of the rotating disc 51 is fixedly connected with an installation cylinder 52. The installation cylinder 52 is a cylindrical structure with an open bottom. A fixed bracket 53 is fixed at the middle position inside the installation cylinder 52. The fixed bracket 53 is composed of a ring and struts installed between the outer wall of the ring and the inner wall of the installation cylinder 52. Synchronous moving components are arranged at both the upper and lower ends of the fixed bracket 53, and the upper and lower synchronous moving components are symmetrically distributed. Among them, the lower synchronous moving component includes a cylinder 54 fixedly installed at the ring. The bottom end of the telescopic section of the cylinder 54 is fixedly installed with a fixed circular plate 55. The outer circumference of the fixed circular plate 55 is rotatably connected with a rotating ring 56. The synchronous moving component also includes vertical plates 58 arranged in a circular distribution inside the installation cylinder 52. Two parallel hinge rods 57 are arranged between the rotating ring 56 and each vertical plate 58. The two ends of the hinge rod 57 are respectively hinged to the rotating ring 56 and the vertical plate 58.

[0050] By driving the fixed circular plate 55 to move in the vertical direction through the telescopic movement of the cylinder 54, the vertical plates 58 are driven to reciprocate in the horizontal direction under the pushing action of the hinge rods 57.

[0051] Continue to refer to Figure 5 , Figure 12 and Figure 13 , the placement device 5 further includes a bending part 50 for bending the second main reinforcement 41 and a clamping part 59 for restricting the bent part of the second main reinforcement 41. Both the clamping part 59 and the bending part 50 are multiple and are evenly distributed in a circle. The clamping part 59 and the bending part 50 correspond one by one, and the clamping part 59 is located below the bending part 50. The clamping part 59 includes two L-shaped telescopic rods 591 arranged vertically and sliding through the side wall of the installation cylinder 52. The L-shaped telescopic rods 591 are fixedly connected with the vertical plates 58 in the lower synchronous moving component; the bending part 50 includes a push block 501 sliding through the side wall of the installation cylinder 52. The push block 501 is fixedly connected with the vertical plates 58 in the upper synchronous moving component. A sliding groove 502 is opened at one end of the push block 501 extending out of the installation cylinder 52. A spring 504 is fixedly connected to the bottom of the sliding groove 502. The bending part 50 further includes a push plate 503. The push plate 503 is composed of a T-shaped slider slidably arranged in the sliding groove 502 and an arc-shaped push plate fixed on the outer wall of the T-shaped slider. The concave surface of the arc-shaped push plate abuts against the outer end of the push block 501, and the bottom of the arc-shaped push plate is lower than the bottom of the push block 501.

[0052] It should be noted that when the pushing block 501 drives the pushing plate 503 to move outwards to bend the second main reinforcement 41, the pushing plate 503 will receive a reaction force from the inclined second main reinforcement 41, causing the T-shaped slider on the pushing plate 503 to move upwards along the sliding groove 502, and the spring 504 will be stretched. When the bending is completed and the placing device 5 moves upwards, the spring 504 gradually returns to its original position. At this time, the pushing plate 503 can still press against the second main reinforcement 41 to maintain pressure for a period of time to ensure the inclination of the second main reinforcement 41 after bending.

[0053] Please refer to Figure 13 , a plurality of circular grooves are formed on the circumferential outer wall of the rotating disk 51. The circular grooves are used to cooperate with external steel bars. The steel bars are inserted into the circular grooves, and by pushing the steel bars, the rotating disk 51 and the mounting cylinder 52 are driven to rotate, so that the bending part of the L-shaped telescopic rod 591 can abut against the outer wall of the second main reinforcement 41.

[0054] The present invention also provides a construction method for a PHC pile of a concrete tapered integrated pile tip, including the following steps: S1. Pile tip fixing: First, fix the bolt 16 on the mounting hole at the bottom of the PHC pipe pile 1, and then butt the mounting hole on the concrete pile tip 3 against the corresponding bolt 16. Then, weld the metal ring 15 on the PHC pipe pile 1 and the metal ring 15 on the concrete pile tip 3 by welding, and apply an anti-rust layer on the outer surface of the connection between the PHC pipe pile 1 and the concrete pile tip 3, and apply an asphalt anti-corrosion layer on the outer surface of the PHC pipe pile 1.

[0055] S2. Pile driving: Use a pile driver to press the PHC pipe pile 1 with the concrete pile tip 3 into the soil.

[0056] S3. Pile splicing: Stop pile driving at a position 1 meter above the ground at the top end of the lower PHC pipe pile 1, and fix the upper PHC pipe pile 1. The fixing method between adjacent two PHC pipe piles 1 is the same as the fixing method between the concrete pile tip 3 and the PHC pipe pile 1, and then continue pile driving.

[0057] S4. Pile feeding: When the pile top is close to the design elevation, use a pile feeder to send the pile to the design elevation.

[0058] S5. Core filling concrete: Fix the pile core steel cage 4 through the placing device 5, and the vertical plates 58 in the lower synchronous moving assembly extend outwards synchronously until the uppermost second stirrup 42 is located between the two L-shaped telescopic rods 591; then insert the external steel bars into the circular grooves of the rotating disk 51, and drive the rotating disk 51 and the mounting cylinder 52 to rotate by pushing the steel bars, so that the bending part of the L-shaped telescopic rod 591 can abut against the outer wall of the second main reinforcement 41. If the bending part cannot abut, use the synchronous moving assembly to pull the L-shaped telescopic rod 591 to move inwards synchronously.

[0059] After that, an external lifting device is used to drive the placement device 5 to descend, so that the pile core steel reinforcement cage 4 descends synchronously. If the positioning holes 431 on the supporting plate 43 are not aligned with the corresponding reinforcing bars 23, the reinforcing bars can also be continuously pushed, so that the clamping part 59 drives the second main reinforcing bar 41 and the supporting plate 43 to rotate, and during the lowering process, it is ensured that the reinforcing bar 23 can pass through the positioning hole 431.

[0060] During the process of gradually placing the pile core steel reinforcement cage 4 into the PHC pipe pile 1, the reinforcing bar 23 will first penetrate through the corresponding positioning hole 431. After that, the reinforcing component 44 will gradually approach the top end of the reinforcing bar 23. When the bottom end of the rotating plate 442 contacts the reinforcing bar 23, the rotating plate 442 will be subjected to an upward pushing force from the reinforcing bar 23, causing the rotating plate 442 to gradually rotate towards the horizontal state. Both ends of the rotating plate 442 are anti-slip layers with a large coefficient of friction. When the rotating plate 442 approaches the horizontal state, both ends of the rotating plate 442 are in close contact with the outer wall of the second main reinforcing bar 41 and the inner wall of the PHC pipe pile 1 respectively. At this time, the supporting plate 43 has also been placed on the supporting member 22.

[0061] The vertical plates 58 in the synchronous moving assembly above extend outwards synchronously and push the bent part 50 towards the second main reinforcing bar 41. With the continuous pushing of the bent part 50, the second main reinforcing bar 41 will gradually bend and abut against the inner wall of the top end of the PHC pipe pile 1, increasing the frictional force of contact between the second main reinforcing bar 41 and the PHC pipe pile 1.

[0062] When the second main reinforcing bar 41 is bent in place, first rotate the rotating disk 51 in the reverse direction, then the upper and lower synchronous moving assemblies retract, and then use an external lifting device to drive the placement device 5 to rise, and pour the slightly expanding concrete 6 towards the position of the pile core steel reinforcement cage 4.

[0063] S6. Pile cutting: After the slightly expanding concrete 6 solidifies, the over-poured part is chiseled off.

[0064] S7. Detection: Conduct pile integrity detection and single-pile vertical bearing capacity detection on the pile foundation after pile cutting.

[0065] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0066] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and defined, the terms "arranged", "connected", "installed", and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, an integral connection, or a sliding connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0067] The embodiments of the specific implementation manners are all preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A PHC pile with a concrete conical integrated pile tip, comprising a PHC pipe pile and a concrete pile tip fixed at the bottom of the PHC pipe pile, a pile core steel cage is placed inside the PHC pipe pile near the top, the pile core steel cage comprises a plurality of No. 2 main bars and No. 2 stirrups welded to the outside of the No. 2 main bars, a support plate is fixed to the bottom of the plurality of No. 2 main bars, and micro-expansion concrete is poured inside the PHC pipe pile and at the position of the pile core steel cage, characterized in that: It also includes a load-bearing assembly arranged in the PHC pile, at least two load-bearing assemblies are distributed in the upper and lower parts, and the load-bearing assembly includes a plurality of metal mounting pipes and a supporting member fixedly connected to the metal mounting pipes, and one end of the metal mounting pipe close to the axis of the PHC pile is flush with the inner wall of the PHC pile, and the end is open; The supporting member comprises a round rod arranged inside the metal mounting tube and a rectangular plate fixed at the end of the round rod, a circular through hole is opened on the rectangular plate, and reinforcing steel bars are penetrated through the upper and lower supporting members facing each other, and a sealing plate for supporting the reinforcing steel bars is fixed at the bottom end of the PHC pile; Positioning holes corresponding to the reinforcing steel bars are provided near the edge of the upper surface of the support plate, the support plate is placed on a plurality of supporting members, and the reinforcing steel bars penetrate the corresponding positioning holes, and the pile core steel bar cage also includes reinforcement components corresponding to the reinforcing steel bars; The lowering of the pile core reinforcement cage is completed by a placing device, and before pouring the micro-expansive concrete, the placing device is removed from the PHC pile.

2. The PHC pile with a concrete conical integrated pile tip according to claim 1, characterized in that: The PHC pipe pile includes a steel cage and a concrete pipe pile cast outside the steel cage and solidified into shape. The steel cage includes a plurality of No. 1 main bars distributed in a circumference, a No. 1 stirrup welded outside the No. 1 main bar, and a reinforcing bar welded inside the No. 1 main bar. There are a plurality of No. 1 stirrups and reinforcing bars distributed from top to bottom. Both ends of the concrete pipe pile and the large-diameter end of the concrete pile tip are provided with metal rings, and a plurality of circumferentially distributed mounting holes are opened on the metal rings. Bolts are commonly provided in the corresponding mounting holes on the PHC pipe pile and the concrete pile tip, and the metal ring on the PHC pipe pile is welded and fixed to the metal ring on the concrete pile tip.

3. The PHC pile with a concrete conical integrated pile tip according to claim 2, characterized in that: During the pile driving process, when the height of a single PHC pipe pile is insufficient, it is necessary to connect the piles. The fixing method of the connected piles is the same as the fixing method of the PHC pipe piles and the concrete pile tips. The load-bearing component is located in the uppermost PHC pipe pile, and the metal mounting pipe is fixed to the No. 1 main reinforcement by welding, and several metal mounting pipes all point to the axis of the PHC pipe pile.

4. The PHC pile with a concrete conical integrated pile tip according to claim 1, characterized in that: The reinforcement assembly includes an L-shaped mounting frame fixed to the outside of the No. 2 main reinforcement. A groove is provided at the top of the vertical section of the L-shaped mounting frame. A rotating plate is rotatably arranged in the groove. A counterweight block is also fixed to the end of the rotating plate close to the inner wall of the PHC pile. The rotating plate is in an inclined state under the action of the lever principle, and the projection length of the rotating plate on the horizontal plane after the inclination is less than the distance from the No. 2 main reinforcement to the inner wall of the PHC pile.

5. The PHC pile with a concrete conical integrated pile tip according to claim 4, characterized in that: During the downward movement of the rotating plate, the reinforcing steel bars will push it upward, causing the rotating plate to gradually rotate toward a horizontal state. Both ends of the rotating plate are anti-slip layers. When the rotating plate is close to a horizontal state, the two ends of the rotating plate are tightly in contact with the outer wall of the No. 2 main reinforcement and the inner wall of the PHC pile respectively. At this time, the support plate is placed on the supporting member.

6. The PHC pile with a concrete conical integrated pile tip according to claim 1, characterized in that: The placing device includes a rotating disk, the top of which is rotatably connected to an external lifting device, and the bottom of the rotating disk is fixedly connected to a mounting cylinder, which is a cylindrical structure with an open bottom. A fixed bracket is fixed to the middle position of the inside of the mounting cylinder, and synchronous moving components are provided at the upper and lower ends of the fixed bracket, and the upper and lower synchronous moving components are symmetrically distributed. The placing device also includes a bending portion for bending the No. 2 main reinforcement and a clamping portion for limiting the bending position of the No. 2 main reinforcement, the upper synchronous moving component is used to push the bending portion, and the lower synchronous moving component is used to push the clamping portion, and the clamping portion and the bending portion are both multiple and evenly distributed circumferentially, and the clamping portion corresponds to the bending portion one by one.

7. The PHC pile with a concrete conical integrated pile tip according to claim 6, characterized in that: The fixed bracket consists of a circular ring and a support rod installed between the outer wall of the circular ring and the inner wall of the mounting cylinder. The synchronous moving component below includes a cylinder fixedly installed on the circular ring. A fixed circular plate is fixedly installed on the bottom end of the telescopic section of the cylinder. The outer circumference of the fixed circular plate is rotatably connected to a rotating ring. The synchronous moving component also includes an upper and lower parallel hinged rod arranged inside the mounting cylinder and distributed in a circular pattern. Two ends of the hinged rod are respectively hinged to the rotating ring and the vertical plate.

8. The PHC pile with a concrete conical integrated pile tip according to claim 7, characterized in that: The clamping part includes two L-shaped telescopic rods distributed up and down and slidingly penetrating the side wall of the mounting cylinder, and the L-shaped telescopic rods are fixedly connected to the synchronous moving assembly below; The bending portion includes a push block that slides through the side wall of the mounting cylinder, the push block is fixedly connected to the synchronous moving component above, a sliding groove is provided at one end of the push block extending out of the mounting cylinder, a spring is fixedly connected to the bottom of the sliding groove, and the bending portion also includes a push plate, wherein the push plate is composed of a T-shaped slider that is slidably arranged in the sliding groove and an arc-shaped push plate fixed to the outer wall of the T-shaped slider, the inner concave surface of the arc-shaped push plate abuts against the outer end of the push block, and the bottom of the arc-shaped push plate is lower than the bottom of the push block.

9. A construction method for a PHC pile with a concrete conical integrated pile tip as claimed in claim 1, characterized in that: The following steps are involved: S1. Pile tip fixing: fix the concrete pile tip at the bottom of the PHC pile, apply an anti-rust layer on the outer surface of the connection between the PHC pile and the concrete pile tip, and apply an asphalt anti-corrosion layer on the outer surface of the PHC pile; S2, pile driving: use a pile driver to drive the PHC pile with concrete pile tip into the soil; S3, pile connection: stop pile pressing when the top of the lower PHC pile is 1 meter above the ground, fix the upper PHC pile, and then continue to sink the pile; S4. Pile delivery: When the pile top is close to the design elevation, use the pile delivery device to deliver the pile to the design elevation; S5, core filling concrete: put the pile core steel cage into the PHC pipe pile through the placing device, so that the PHC pipe pile and the pile core steel cage are in close contact, then bend the No. 2 main reinforcement and press it on the top of the PHC pipe pile, and then pour micro-expansion concrete into the position of the pile core steel cage; S6. Pile cutting: After the micro-expansion concrete solidifies, the over-filled part will be chiseled off; S7. Inspection: Carry out pile body integrity inspection and single pile vertical bearing capacity inspection on the pile foundation after pile cutting.

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