PHC Pile with a Concrete Conical Integrated Pile Tip and Its Construction Method

Abstract

The present invention relates to the technical field of PHC pile construction, specifically to a PHC pile with a concrete conical integrated pile tip and its construction method. The PHC pile with the concrete conical integrated pile tip includes a PHC pipe pile and a concrete pile tip fixed at the bottom of the PHC pipe pile. A pile core steel reinforcement cage is placed near the top inside the PHC pipe pile, and slightly expanded concrete is poured inside the PHC pipe pile at the position of the pile core steel reinforcement cage. The PHC pile with the concrete conical integrated pile tip further includes a load-bearing component arranged inside the PHC pipe pile; 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 reinforcement cage, and on the other hand, it cooperates with the reinforcement component of the pile core steel reinforcement cage to increase the extrusion force between the pile core steel reinforcement cage and the PHC pipe pile, thereby increasing the stability and firmness of the placement of the pile core steel reinforcement cage.

Description

Technical Field

[0001] The present invention relates to the technical field of PHC pile construction, and particularly 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 members 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 soils, a pile tip needs to be added at the bottom of the PHC pipe pile to better break the ground; they are also widely used in various building engineering foundations such as high-rise and 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. Currently, 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 tray of the pile core steel cage. Before it solidifies, there is a severe test for the bearing capacity of the pile core steel cage, and 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 art 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 tray is fixedly arranged at the bottom of the plurality of second main steel bars. Slightly 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 assembly arranged inside the PHC pipe pile. At least two load-bearing assemblies are distributed up and down. The load-bearing assembly 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. The reinforcing steel bars penetrate through the supporting members that are directly opposite to each other vertically. A sealing plate for supporting the reinforcing steel bars 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 at positions near the edge of the upper surface of the supporting plate. 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 the placing device is removed from the PHC pipe pile before pouring the slightly expanded concrete.

[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 distributed in a circumferential manner are provided on the metal rings. 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 for pile splicing is the same as the fixing method for 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 and the bending part correspond to each other one by one.

[0014] In a possible implementation manner, the fixing bracket is composed of a circular ring and support rods 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 formed 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 fixation: 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 driving: 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 expanded concrete into the position of the pile core steel cage.

[0022] S6. Pile cutting: After the slightly expanded 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 well.

[0032] Figure 7 This is a schematic diagram of the bending of the No. 2 main reinforcement of the pile core reinforcement cage.

[0033] Figure 8 This is a schematic diagram of the top PHC pile after micro-expansive concrete is poured into it.

[0034] Figure 9 It is a partial structural diagram of the load-bearing components and PHC piles.

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

[0036] Figure 11 It is a schematic diagram of the local structure of the placement device for fixing the pile core reinforcement cage.

[0037] Figure 12 yes Figure 11 Schematic diagram of the three-dimensional structure after cutting.

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

[0039] Figure 14 It is a three-dimensional structural diagram of the supporting parts and reinforcing steel bars.

[0040] In the figure: 1. PHC pile; 11. No. 1 main reinforcement; 12. No. 1 stirrup; 13. Reinforcement; 14. Concrete pile; 15. Metal ring; 16. Bolt; 17. Closing plate; 2. Load-bearing component; 21. Metal installation pipe; 22. Supporting member; 23. Reinforcement steel bar; 3. Concrete pile tip; 4. Pile core steel cage; 41. No. 2 main reinforcement; 42. No. 2 stirrup; 43. Support plate; 431. Positioning hole; 44. Reinforcement component; 44 1. L-shaped mounting frame; 442. rotating plate; 443. counterweight; 5. placing device; 51. rotating disk; 52. mounting cylinder; 53. fixed bracket; 54. cylinder; 55. fixed circular plate; 56. rotating ring; 57. hinged rod; 58. vertical plate; 59. clamping part; 591. L-shaped telescopic rod; 50. bending part; 501. push block; 502. sliding groove; 503. push plate; 504. spring; 6. micro-expansive concrete. DETAILED DESCRIPTION

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of 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 violating the connotation of the present invention, so the present invention is not limited by the specific embodiments 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, a first stirrup 12 welded outside the first main reinforcements 11, and a reinforcing bar 13 welded inside the first main reinforcements 11. The first stirrup 12 and the reinforcing bar 13 are each provided with a plurality of them from top to bottom, and the number of the reinforcing bars 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 formed in a circumferential manner on the metal ring 15. When fixing the concrete pile tip 3 and the PHC pipe pile 1 together, it is necessary to first fix the bolts 16 to the mounting holes at the bottom of the PHC pipe pile 1, and then dock the mounting holes on the concrete pile tip 3 to the corresponding bolts 16, and 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 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 for pile splicing is the same as the fixing method for 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 support 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 support member 22 includes a round bar inserted into the metal mounting pipe 21 and a rectangular plate fixed to the end of the round bar. A circular through hole is formed in the rectangular plate. The support 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 support 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 support 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 practical 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 bar 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 thread 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 cage 4 extending into the PHC pipe pile 1 subsequently. On the other hand, the load-bearing assembly 2 can also enhance the friction between the PHC pipe pile 1 and the pile core steel cage 4.

[0046] Please refer to Figure 4 、 Figure 5 、 Figure 6 、 Figure 8 and Figure 10 , in the uppermost PHC pipe pile 1, a pile core steel cage 4 is placed. The pile core steel 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. There are several second stirrups 42 arranged from top to bottom. The bottoms of several second main reinforcement bars 41 are jointly fixed with a support plate 43. Positioning holes 431 are opened at positions near the edge of the upper surface of the support plate 43. The positioning holes 431 correspond to the reinforcement bars 23 one by one. The support plate 43 is placed on several supporting members 22, and the reinforcement bars 23 pass through the corresponding positioning holes 431. The pile core steel 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 opened at the top end 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 will not hinder the descending process during the downward placement of the pile core steel 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 inserting the pile core steel reinforcement cage 4 into the PHC pipe pile 1, the reinforcement steel bar 23 will first pass through the corresponding positioning hole 431, and then the reinforcement assembly 44 will gradually approach the top of the reinforcement steel bar 23. When the bottom end of the rotating plate 442 contacts the reinforcement steel bar 23, the rotating plate 442 will be subjected to an upward thrust from the reinforcement steel 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 second main reinforcement bar 41 after bending 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 , the 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 placing device 5. The placing device 5 includes a rotating disk 51. The top end of the rotating disk 51 is rotatably connected to an external lifting device (such as a cylinder or a hydraulic cylinder). The bottom end of the rotating disk 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. 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 further includes vertical plates 58 arranged in a circumferential 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] The telescopic movement of the cylinder 54 drives the fixed circular plate 55 to move in the vertical direction, so that the vertical plate 58 reciprocates in the horizontal direction under the pushing action of the hinge rod 57.

[0051] Continue to refer to Figure 5 , Figure 12 and Figure 13 , the placing device 5 further includes a bending part 50 for bending the second main reinforcement 41 and a reinforcing bar clamping part 59 for restricting the bent part of the second main reinforcement 41. Both the reinforcing bar clamping part 59 and the bending part 50 are multiple and are evenly distributed in a circumferential manner. The reinforcing bar clamping part 59 and the bending part 50 correspond to each other one by one, and the reinforcing bar clamping part 59 is located below the bending part 50. The reinforcing bar 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 to the vertical plate 58 in the lower synchronous moving component. The bending part 50 includes a pushing block 501 sliding through the side wall of the installation cylinder 52. The pushing block 501 is fixedly connected to the vertical plate 58 in the upper synchronous moving component. A sliding groove 502 is opened at one end of the pushing 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 pushing plate 503. The pushing plate 503 is composed of a T-shaped slider slidably arranged in the sliding groove 502 and an arc-shaped pushing plate fixed on the outer wall of the T-shaped slider. The concave surface of the arc-shaped pushing plate abuts against the outer end of the pushing block 501, and the bottom of the arc-shaped pushing plate is lower than the bottom of the pushing block 501.

[0052] It should be noted that when the pushing block 501 drives the pushing plate 503 to move outward 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 upward along the sliding groove 502, and the spring 504 will be stretched. When the bending is completed and the placing device 5 moves upward, 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 provided 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 conical integrated pile tip, including the following steps: S1. Pile tip fixation: First, fix the bolts 16 on the mounting holes at the bottom of the PHC pipe pile 1, and then dock the mounting holes on the concrete pile tip 3 with the corresponding bolts 16. Then, weld the metal rings 15 on the PHC pipe pile 1 and the metal rings 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 outward 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 inward synchronously.

[0059] After that, an external lifting device is used to drive the placing device 5 to descend, so that the pile core steel reinforcement cage 4 descends synchronously. If the positioning hole 431 on the supporting plate 43 is not aligned with the corresponding reinforcing steel bar 23, the steel bar can also be continuously pushed, so that the clamping part 59 drives the second main steel bar 41 and the supporting plate 43 to rotate, and during the lowering process, it is ensured that the reinforcing steel 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 steel 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 steel bar 23. When the bottom end of the rotating plate 442 contacts the reinforcing steel bar 23, the rotating plate 442 will receive an upward pushing force from the reinforcing steel 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 steel 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 plate 58 in the upper synchronous moving component extends outwards synchronously and pushes the bent part 50 towards the second main steel bar 41. With the continuous pushing of the bent part 50, the second main steel 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 steel bar 41 and the PHC pipe pile 1.

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

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

[0064] S7. Detection: The pile integrity detection and the single-pile vertical bearing capacity detection are carried out 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", "beneath" and "under" 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 can be a fixed connection, a detachable connection, an integral connection, or a sliding connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can 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 reinforcement cage is placed near the top inside the PHC pipe pile. The pile core steel reinforcement cage includes a number of second main reinforcements and second stirrups welded outside the second main reinforcements. A supporting plate is fixedly provided at the bottom of the number of second main reinforcements. Micro-expansion concrete is poured inside the PHC pipe pile at the position of the pile core steel reinforcement cage. It is characterized in that: It further includes a load-bearing component arranged inside the PHC pipe pile. At least two load-bearing components are distributed vertically. The load-bearing component includes a number 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; The supporting member includes a round rod arranged inside the metal installation pipe and a rectangular plate fixed at the end of the round rod. A circular through hole is provided on the rectangular plate. 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 at the bottom end of the PHC pipe pile; Positioning holes corresponding to the reinforcing steel bars one by one are provided at the position near the edge of the upper surface of the supporting plate. The supporting plate is placed on a number of supporting members, and the reinforcing steel bars penetrate through the corresponding positioning holes. The pile core steel reinforcement cage further includes a reinforcing component corresponding to the reinforcing steel bar one by one; The lowering of the pile core steel reinforcement cage is completed by a placing device. Before pouring the micro-expansion concrete, the placing device is removed from the PHC pipe pile; The reinforcing component includes an L-shaped mounting bracket fixed outside the second main reinforcement. A groove is provided at the top of the vertical section of the L-shaped mounting bracket. A rotating plate is rotatably arranged in the groove. A counterweight block is further fixed at 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 reinforcement and the inner wall of the PHC pipe pile; During the downward movement of the rotating plate, it will be subjected to an upward pushing force from the reinforcing steel bar, 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 reinforcement and the inner wall of the PHC pipe pile respectively. At this time, the supporting plate is placed on the supporting member.

2. The PHC pile with a concrete tapered integrated pile tip according to claim 1, characterized in that: The PHC pipe pile includes a steel reinforcement cage and a concrete pipe pile poured outside the steel reinforcement cage and solidified. The steel reinforcement cage includes a number of first main reinforcements distributed in a circular pattern, first stirrups welded outside the first main reinforcements, and reinforcing ribs welded inside the first main reinforcements. A number 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 number of mounting holes are provided on the metal rings in a circular pattern. Bolts are commonly arranged 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 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 that of the PHC pipe pile and the concrete pile tip. The load-bearing component is located inside the uppermost PHC pipe pile. The metal installation pipe is fixed to the No. 1 main reinforcement by welding, and several metal installation 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, wherein: The placing device includes a rotating disc. The top end of the rotating disc is rotatably connected to an external lifting device. The bottom end of the rotating disc 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 No. 2 main reinforcement and a clamping part for restricting the bent part of the No. 2 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 clamping part. Both the clamping part and the bending part are multiple and are evenly distributed in a circle, and the clamping part and the bending part correspond to each other one by one.

5. The PHC pile with a concrete conical integrated pile tip according to claim 4, characterized in that: The fixing bracket is composed of a ring and support rods installed between the outer wall of the ring and the inner wall of the installation cylinder. The lower synchronous moving component includes a cylinder fixedly installed at the ring. The bottom end of the telescopic section of the cylinder is fixedly installed with a fixed circular plate. A rotating ring is rotatably connected to the outer periphery of the fixed circular plate. The synchronous moving component further includes vertical plates arranged inside the installation cylinder and distributed in a circle. 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.

6. The PHC pile with a concrete tapered integrated pile tip according to claim 5, characterized in that: The clamping part includes two L-shaped telescopic rods arranged vertically and sliding through the side wall of the installation cylinder. The L-shaped telescopic rods are fixedly connected to the lower synchronous moving component. The bending part includes a push block sliding through the side wall of the installation cylinder. 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. 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.

7. A construction method of a PHC pile with a concrete conical integrated pile tip as described in claim 1, characterized in that, It includes the following steps: S1. Pile tip fixation: Fix the concrete pile tip at the bottom of the PHC pipe pile, and 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. S2. Pile sinking: Use a pile driver to press the PHC pipe pile with a concrete pile tip into the soil. S3. Pile splicing: Stop pile pressing at a position 1 meter above the ground at the top end of the lower PHC pipe pile, and fix the upper PHC pipe pile, and then continue pile sinking. 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. S5. Core-filled concrete: Lower the pile core steel reinforcement cage into the PHC pipe pile through a placing device so that the PHC pipe pile and the pile core steel reinforcement cage are in close contact. Then, bend the No. 2 main reinforcement bar and press it on the top of the PHC pipe pile, and then pour slightly expanded concrete at the position of the pile core steel reinforcement cage; S6. Pile cutting: After the slightly expanded concrete solidifies, chisel off the over-poured part; S7. Testing: Conduct pile integrity testing and single-pile vertical bearing capacity testing on the pile foundation after pile cutting.

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