A prestressed pipe pile hole ramming expansion composite pile and construction method

Abstract

The present invention relates to the technical field of foundation composite piles, and specifically proposes a prestressed pipe pile hole rammed and expanded composite pile and a construction method. The prestressed pipe pile hole rammed and expanded composite pile comprises: a prefabricated hollow pipe pile, a core-filling steel cage, a rammed and expanded head steel cylinder, a connector, and a rammed and expanded head carrier at the bottom of the pile. The present invention cooperates the prefabricated hollow pipe pile with the rammed and expanded head steel cylinder and the pile bottom closing device, so that the prefabricated hollow pipe pile and the rammed and expanded head steel cylinder serve as both a bearing member and a casing, forming a construction method of first sinking the pile and then ramming and expanding the core, without the need to lift the steel casing, thereby improving the construction efficiency, and the filler is dispersed circumferentially from the bottom of the rammed and expanded head steel cylinder to the outer wall of the rammed and expanded head steel cylinder, so that the formed pile bottom end rammed and expanded head carrier is formed by the rammed and expanded head steel cylinder and its inner and outer walls filled and wrapped with dry hard concrete, further improving the overall firmness of the prestressed pipe pile hole rammed and expanded composite pile.

Description

Technical Field

[0001] This invention relates to the field of foundation composite pile technology, and specifically proposes a prestressed pipe pile in-hole rammed and expanded composite pile and its construction method. Background Technology

[0002] Composite carrier piles consist of a concrete pile body and a rammed carrier at the pile bottom. Traditional construction methods generally involve vibrating and sinking a steel casing, pulling it out, filling and ramming the filling material into the hole through the steel casing, and then lowering the reinforcing cage and pouring the concrete pile body.

[0003] However, during the ramming and expansion of the fill material, the lateral impact of the ramming is large, which can easily cause soil squeezing and negatively affect adjacent piles. The compaction degree is also difficult to control. The length of the construction pile is limited by the height of the equipment, making it difficult to pull out the steel sleeve for long pile construction. Ordinary hammering methods are not suitable for construction in soil layers with hard interlayers. The ramming of the fill material generates vibration. When the water level at the construction site is high, water sealing and water stoppage are required. The process is complex, restrictive, and has a long construction period, making it difficult to guarantee the quality. Furthermore, after the reinforcement cage is inserted, when the concrete is poured and vibrated, the reinforcement cage is prone to shaking under the vibration force of the concrete, which affects the quality of the composite carrier pile. Therefore, a method for ramming and expanding prestressed pipe piles in the borehole and its construction is proposed to solve the above problems. Summary of the Invention

[0004] In view of the above problems, this application provides a prestressed pipe pile in-hole rammed and expanded composite pile and construction method to solve the technical problems in the related art.

[0005] To achieve the above objectives, this application provides the following technical solution: a prestressed pipe pile with in-hole rammed and enlarged composite pile, comprising a precast hollow pipe pile, a core-filled steel cage, a rammed and enlarged head steel cylinder, a connector, and a rammed and enlarged head carrier at the bottom of the pile. The precast hollow pipe pile has a hollow circular hole inside. A connecting sleeve is installed at the bottom of the precast hollow pipe pile by high-strength bolts. The lower end of the connecting sleeve is installed with a rammed and enlarged head steel cylinder by high-strength bolts. The rammed and enlarged head steel cylinder is cylindrical and concentric with the precast hollow pipe pile with the same inner diameter.

[0006] The lower end of the tamping enlarged head steel cylinder and the lower end of the inner ring surface of the connecting sleeve are both provided with annular grooves. During the static pressure pile driving operation, the bottom of the tamping enlarged head steel cylinder is sealed by a pile bottom sealing device.

[0007] After the static pressure pile driving operation of the precast hollow pipe pile is completed, the pile bottom sealing device is moved upward to the outside of the precast hollow pipe pile. Filler and dry hard concrete are put into the precast hollow pipe pile one by one and compacted to form the pile bottom end compacted enlarged head carrier.

[0008] The lower end of the core-filling steel cage is equipped with a connector that engages with the annular groove on the connecting sleeve. When the core-filling steel cage is installed into the precast hollow pipe pile, the connector at the lower end of the core-filling steel cage is inserted into the annular groove on the inner wall of the connecting sleeve to limit and lock the core-filling steel cage.

[0009] The upper end of the core-filling steel cage inside the precast hollow pipe pile is connected to the pile cap steel bar. The core-filling steel cage and the pile cap steel bar are poured with self-compacting concrete of the same grade as the precast hollow pipe pile. Vibration compaction and solidification are used to obtain the required prestressed pipe pile hole rammed and expanded composite pile.

[0010] In one possible implementation, the pile bottom sealing device includes a support ring and a pile bottom steel plate arranged sequentially from top to bottom. A hollow connecting sleeve is installed on the inner ring surface of the support ring and the top of the pile bottom steel plate. The inner ring surface of the support ring is fixedly connected to the hollow connecting sleeve by a connecting strip. Guide grooves are evenly arranged around the circumference of the hollow connecting sleeve near the lower end of the side wall of the pile bottom steel plate and the outer ring surface of the support ring. A sliding component that is inserted into the corresponding annular groove is slidably connected on the guide groove. A lifting drive group that pulls the sliding component to slide along the guide groove is installed on the hollow connecting sleeve.

[0011] In one possible implementation, the side wall of the compacting enlarged head steel cylinder is provided with evenly distributed discharge holes, and a sealing sleeve connected to the hollow connecting sleeve via a bracket is fitted on it. The sealing sleeve is inserted into the compacting enlarged head steel cylinder to seal the discharge holes, and the top of the sealing sleeve is connected to the support ring via a rib.

[0012] In one possible implementation, the lifting drive assembly includes a main steel wire rope that slides up and down and is mounted on the top of a hollow connecting sleeve. The side wall of the hollow connecting sleeve has through holes that are evenly arranged along its circumference and correspond one-to-one with the sliding components. A branch steel wire rope is fixedly mounted on the top of the sliding component. The other end of the branch steel wire rope passes through the corresponding through hole and is connected to the main steel wire rope. A friction-reducing guide wheel assembly is installed in the through hole. Elastic reset components are installed between the inner ring surface of the support ring and the middle part of the pile bottom steel plate and the corresponding sliding component.

[0013] In one possible implementation, the friction-reducing guide wheel assembly includes two symmetrically arranged limiting guide wheels, which are rotatably connected to the upper and lower sides of the through hole via mounting bases, and branch steel wire ropes are wound around the corresponding limiting guide wheels.

[0014] In one possible implementation, the elastic reset assembly includes an L-shaped plate whose horizontal end is connected to a sliding assembly. After the L-shaped plate passes through the guide groove, the vertical section of the L-shaped plate is connected to the inner ring surface of the corresponding support ring or the lower inner wall of the hollow connecting sleeve by a reset spring.

[0015] In one possible implementation, the connector is an insertable steel bar that is obliquely installed at the bottom of a ring of reinforcing bars on the outer ring of the filler steel cage.

[0016] The present invention also provides a construction method for prestressed pipe pile in-hole rammed and expanded composite pile, including the following steps: S1, construction preparation: prepare and inspect the construction machinery, instruments, equipment, tools and precast hollow pipe piles.

[0017] S2, Long spiral pre-drilling: According to the design route, a 300mm long φ6mm steel bar is driven into the center of the pile position for positioning; after the pile position is positioned, the long spiral drilling machine is smoothly positioned and centered, the verticality of the drill rod is checked and adjusted, and then the drilling operation is carried out by the long spiral drilling machine. After drilling to the design elevation, the long spiral drilling machine is removed and moved away to obtain the required pile hole.

[0018] S3, Cleaning the inner wall of the pile hole: Clean the pile hole using the existing cleaning equipment. After cleaning, inspect and accept the diameter and vertical flatness of the pile hole.

[0019] S4, Pipe Pile Bottom Sealing: When the precast hollow pipe pile drives the tamping enlarged head steel cylinder to sink to the bottom of the pile hole, the sliding component on the pile bottom sealing device is inserted into the corresponding annular groove. At this time, the pile bottom steel plate and the support ring are locked by vertical displacement, and the pile bottom steel plate will seal the bottom of the tamping enlarged head steel cylinder.

[0020] S5, Static pressure pile driving of pipe piles: The precast hollow pipe pile and the tamped enlarged head steel cylinder below it are lifted and fed into the pile hole by the existing special crane. After the precast hollow pipe pile and the tamped enlarged head steel cylinder below it are transported to the vicinity of the existing pile driver, the pile driver drives the precast hollow pipe pile and the tamped enlarged head steel cylinder and presses the precast hollow pipe pile and the tamped enlarged head steel cylinder into the pile hole, pressing the tamped enlarged head steel cylinder at the lower end of the precast hollow pipe pile to the design elevation.

[0021] S6, Pipe Pile Bottom Opening: After the precast hollow pipe pile and its bottom compacted enlarged head steel cylinder sink to the design elevation, the lifting drive group on the pile bottom sealing device is driven by the drive source to pull the sliding component to move and disengage from the corresponding annular groove. Then, the pile bottom steel plate, support ring and lifting drive group are moved upward out of the precast hollow pipe pile, thereby opening the bottom of the compacted enlarged head steel cylinder.

[0022] S7, Column hammer filling and compaction: Filling material is introduced from the upper inlet of the precast hollow pipe pile, and then the column hammer is used to compact the filling material in free fall until the compaction meets the requirements; then the column hammer is lifted to fill dry hard concrete, and the dry hard concrete is continued to be compacted to the bottom of the precast hollow pipe pile until the compacted enlarged head carrier at the bottom of the pile is formed.

[0023] S8, Installation of the core-filled steel cage: First, pull the column hammer out to the outside of the precast hollow pipe pile, then insert the core-filled steel cage into the precast hollow pipe pile until the bottom of the core-filled steel cage contacts the top of the compacted enlarged head carrier at the bottom of the pile. At this time, the plug at the lower end of the core-filled steel cage is inserted into the annular groove opened in the inner wall of the connecting sleeve to limit and lock the core-filled steel cage.

[0024] S9, Installation of pile cap reinforcement and formwork: Lay a layer of graded crushed stone about 10cm thick around the top of the precast hollow pipe pile and compact it; then tie the pile cap reinforcement, which is tied to the filling reinforcement cage inside the precast hollow pipe pile, ensuring that the precast hollow pipe pile extends 5cm into the pile cap reinforcement; finally, install the pile cap side formwork around the pile cap reinforcement.

[0025] S10, Concrete pouring: The same grade of self-compacting concrete as the precast hollow pipe pile is used for the pouring of the core reinforcement cage and the pile cap reinforcement in the precast hollow pipe pile.

[0026] The above-mentioned one or more technical solutions in the embodiments of the present invention have at least one of the following beneficial effects: 1. The prestressed pipe pile in-hole rammed and expanded composite pile and construction method designed in the present invention, through the cooperation of precast hollow pipe piles, rammed and expanded steel cylinders and pile bottom sealing devices, makes the precast hollow pipe piles and rammed and expanded steel cylinders both load-bearing components and casings, forming a construction method of first driving the pile and then ramming and expanding the core, eliminating the need to pull out the steel casing, improving construction efficiency, and when the internal ramming carrier is constructed, the hammer weight remains unchanged, the lateral influence range when ramming the filling material is reduced, and the impact on the loosening of adjacent piles is reduced. At the same time, the filling material is dispersed from the bottom of the rammed and expanded steel cylinder to the outer wall of the rammed and expanded steel cylinder, so that the rammed and expanded carrier at the pile bottom end is formed by the rammed and expanded steel cylinder and its inner and outer walls filled and wrapped with dry hard concrete, further improving the overall firmness of the prestressed pipe pile in-hole rammed and expanded composite pile.

[0027] 2. During the pile driving process, the bottom of the rammed enlarged head steel cylinder is sealed by the pile bottom sealing device, which improves the applicability of the rammed enlarged composite pile in the prestressed pipe pile hole. Furthermore, the support ring in the pile bottom sealing device is connected to the hollow connecting sleeve and the sliding component is inserted into the annular groove on the connecting sleeve, so that the bottom of the connecting sleeve is supported, thereby supporting both the upper and lower sides of the rammed enlarged head steel cylinder, which improves the supporting force and compressive resistance of the rammed enlarged head steel cylinder and the pile bottom steel plate.

[0028] 3. The present invention has a connector installed at the lower end of the core-filling steel cage that engages with the annular groove on the connecting sleeve. When the core-filling steel cage is installed into the precast hollow pipe pile, the connector at the lower end of the core-filling steel cage is inserted into the annular groove on the inner wall of the connecting sleeve to limit and lock the core-filling steel cage. This further improves the connection strength between the core-filling steel cage and the precast hollow pipe pile and prevents the core-filling steel cage from moving up and down under the action of vibration force during the concrete vibration process after concrete pouring, which would affect the quality of the prestressed pipe pile hole rammed and expanded composite pile. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 This is a step diagram illustrating the construction method of the prestressed pipe pile in-hole rammed and expanded composite pile of the present invention.

[0031] Figure 2 This is a schematic diagram of the structure of the pile hole formed after drilling according to the present invention.

[0032] Figure 3 This is a schematic diagram of the construction state structure of construction steps 4 and 5 of the present invention.

[0033] Figure 4 This is a schematic diagram of the structure of the precast hollow pipe pile and the tamped enlarged head steel cylinder of the present invention after they are inserted into the pile hole, the pile bottom sealing device is removed from the precast hollow pipe pile, and dry hard concrete is filled into the precast hollow pipe pile.

[0034] Figure 5 This is a schematic diagram of the construction state structure of construction step 7 of the present invention.

[0035] Figure 6 This is a schematic diagram of the construction state structure in step 8 of the present invention.

[0036] Figure 7 This is a schematic diagram of the construction state structure of step 9 of the present invention.

[0037] Figure 8 This is a schematic diagram of the structure of the prestressed pipe pile in the borehole rammed and expanded composite pile formed in step 10 of the present invention.

[0038] Figure 9 This is the present invention. Figure 6 Enlarged view of point A in the image.

[0039] Figure 10This is a partial structural schematic diagram of the precast hollow pipe pile, the tamped enlarged head steel cylinder, and the pile bottom sealing device of the present invention.

[0040] Figure 11 This is the present invention. Figure 10 Enlarged view of point B in the image.

[0041] Figure 12 This is the present invention. Figure 10 Enlarged view of point C in the image.

[0042] Reference numerals: 1. Precast hollow pipe pile; 2. Filler steel cage; 3. Connecting sleeve; 4. Compactor enlarged head steel cylinder; 40. Discharge hole; 41. Support; 42. Sealing sleeve; 5. Annular groove; 6. Pile bottom sealing device; 60. Support ring; 61. Pile bottom steel plate; 62. Connecting strip; 63. Guide chute; 64. Sliding assembly; 65. Lifting drive assembly; 650. Main wire rope; 651. Through hole; 652. Branch wire rope; 660. L-shaped plate; 661. Return spring; 670. Limiting guide wheel; 671. Mounting seat; 68. Hollow connecting sleeve; 7. Insert connector; 8. Column hammer; 9. Pile bottom end compactor enlarged head carrier; 10. Template; 11. Pile hole. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] See Figure 3 , Figure 4 and Figure 9 A prestressed pipe pile with in-hole rammed and enlarged composite pile includes a precast hollow pipe pile 1, a core-filled steel cage 2, a rammed and enlarged head steel cylinder 4, a connector 7, and a rammed and enlarged head carrier 9 at the bottom of the pile. The precast hollow pipe pile 1 has a hollow circular hole inside. A connecting sleeve 3 is installed at the bottom of the precast hollow pipe pile 1 by a high-strength bolt (not shown in the figure). The lower end of the connecting sleeve 3 is installed with a rammed and enlarged head steel cylinder 4 by a high-strength bolt (not shown in the figure). The rammed and enlarged head steel cylinder 4 is cylindrical and concentric with the precast hollow pipe pile 1 with the same inner diameter.

[0046] See Figure 3 and Figure 10The inner wall of the lower end of the tamping enlarged head steel cylinder 4 and the lower end of the inner ring surface of the connecting sleeve 3 are both provided with annular grooves 5. During the static pressure pile driving operation of the precast hollow pipe pile 1, the bottom of the tamping enlarged head steel cylinder 4 is sealed by a pile bottom sealing device 6 to prevent soil and other impurities from entering the precast hollow pipe pile 1 and the tamping enlarged head steel cylinder 4 to form pile core soil when the precast hollow pipe pile 1 drives the tamping enlarged head steel cylinder 4 for pile driving.

[0047] See Figure 3 , Figure 4 and Figure 5 After the static pressure pile driving operation of the precast hollow pipe pile 1 is completed, the pile bottom sealing device 6 is moved upward to the outside of the precast hollow pipe pile 1. Filler and dry hard concrete are put into the precast hollow pipe pile 1 one by one and compacted to form the pile bottom end compacted enlarged head carrier 9, thereby improving the overall firmness of the precast hollow pipe pile 1.

[0048] See Figure 6 and Figure 9 The lower end of the core-filling steel cage 2 is equipped with a connector 7 that engages with the annular groove 5 on the connecting sleeve 3. When the core-filling steel cage 2 is installed into the precast hollow pipe pile 1, the connector 7 at the lower end of the core-filling steel cage 2 is inserted into the annular groove 5 on the inner wall of the connecting sleeve 3 to limit and lock the core-filling steel cage 2.

[0049] See Figure 7 and Figure 8 The upper end of the core-filling steel cage 2 inside the precast hollow pipe pile 1 is connected to the pile cap steel bar. The core-filling steel cage 2 and the pile cap steel bar are poured using self-compacting concrete of the same grade as the precast hollow pipe pile 1. Vibration compaction and solidification are used to obtain the required prestressed pipe pile hole rammed and expanded composite pile.

[0050] Using precast hollow pipe piles 1 in conjunction with rammed enlarged head steel cylinders 4 as load-bearing members ensures the quality of pile construction. At the same time, dry-hard concrete is filled into the precast hollow pipe piles 1, which avoids the lateral diffusion of dry-hard concrete during ramming. Under the premise of constant hammer weight, the lateral influence range when ramming the filling material is reduced, and the impact on the loosening of adjacent piles is reduced. The quality of the load-bearing member is controlled by penetration, which has the characteristics of immediate compaction. The quality of each link in the entire construction process is controllable.

[0051] See Figure 9The insert 7 is an insert steel bar that is installed at an angle at the bottom of the outer ring of reinforcing bars in the core-filling steel cage 2. As the core-filling steel cage 2 moves downward, the insert steel bar abuts against the top of the compacted enlarged head carrier 9 at the bottom of the pile. At this time, the insert steel bar at the lower end of the core-filling steel cage 2 gradually bends and tilts and inserts into the annular groove 5 opened in the inner wall of the connecting sleeve 3. When the bottom of the core-filling steel cage 2 abuts against the top of the compacted enlarged head carrier 9, the insert steel bar is in a horizontal state and is inserted into the annular groove 5 opened in the inner wall of the connecting sleeve 3, thereby limiting and locking the core-filling steel cage 2, further improving the connection strength between the core-filling steel cage 2 and the precast hollow pipe pile 1, and preventing the core-filling steel cage 2 from moving up and down under the action of vibration force during the concrete vibration process, which would affect the quality of the prestressed pipe pile hole compacted and enlarged composite pile.

[0052] See Figure 3 and Figure 10 The pile bottom sealing device 6 includes a support ring 60 and a pile bottom steel plate 61 arranged sequentially from top to bottom. A hollow connecting sleeve 68 is installed on the inner ring surface of the support ring 60 and the top of the pile bottom steel plate 61. The inner ring surface of the support ring 60 is fixedly connected to the hollow connecting sleeve 68 through a connecting strip 62. Guide grooves 63 are evenly arranged around the circumference of the hollow connecting sleeve 68 near the lower end of the side wall of the pile bottom steel plate 61 and the outer ring surface of the support ring 60. A sliding component 64 that is inserted into and cooperates with the corresponding annular groove 5 is slidably connected on the guide groove 63. A lifting drive group 65 is installed on the hollow connecting sleeve 68 to pull the sliding component 64 to slide along the guide groove 63.

[0053] After the drilling and cleaning of pile hole 11 are completed (see...) Figure 2 Before the precast hollow pipe pile 1 drives the compacted enlarged head steel cylinder 4 to sink to the bottom of the pile hole 11, the sliding component 64 on the pile bottom sealing device 6 is inserted into the corresponding annular groove 5. At this time, the pile bottom steel plate 61 and the support ring 60 are locked by vertical displacement, and the pile bottom steel plate 61 seals the bottom of the compacted enlarged head steel cylinder 4, preventing soil and other impurities in the pile hole 11 from entering the precast hollow pipe pile 1 and the compacted enlarged head steel cylinder 4 to form pile core soil when the precast hollow pipe pile 1 drives the compacted enlarged head steel cylinder 4 to sink to the bottom of the pile hole 11. Through the connection between the support ring 60 and the hollow connecting sleeve 68 and the insertion of the sliding component 64 into the annular groove 5 on the connecting sleeve 3, the bottom of the connecting sleeve 3 is supported, thereby supporting both the upper and lower sides of the compacted enlarged head steel cylinder 4, thereby improving the supporting force and compressive strength of the compacted enlarged head steel cylinder 4 and the pile bottom steel plate 61.

[0054] After the precast hollow pipe pile 1 and its bottom tamping enlarged head steel cylinder 4 sink to the design elevation, the lifting drive group 65 on the pile bottom sealing device 6 is driven by the drive source to pull the sliding component 64 to move and disengage from the corresponding annular groove 5. Then, the pile bottom steel plate 61, support ring 60 and lifting drive group 65 are moved upward out of the precast hollow pipe pile 1, thereby opening the bottom of the tamping enlarged head steel cylinder 4 so that dry hard concrete can be filled into the precast hollow pipe pile 1 and compacted.

[0055] See Figure 7 and Figure 10 The side wall of the compacting enlarged head steel cylinder 4 is provided with evenly arranged discharge holes 40. A sealing sleeve 42 is fitted on the hollow connecting sleeve 68 and connected to it through the bracket 41. The sealing sleeve 42 is inserted into the compacting enlarged head steel cylinder 4 to seal the discharge holes 40. The top of the sealing sleeve 42 is connected to the support ring 60 through a rib.

[0056] The pile bottom sealing device 6 seals the bottom of the compacted enlarged head steel cylinder 4, and the sealing sleeve 42 seals the discharge hole 40 to prevent the silt outside the side wall of the pile hole 11 from entering the compacted enlarged head steel cylinder 4 through the discharge hole 40 when the precast hollow pipe pile 1 drives the compacted enlarged head steel cylinder 4 to sink to the bottom of the pile hole 11. When the bottom of the compacted enlarged head steel cylinder 4 is opened, the pile bottom steel plate 61, the support ring 60 and the lifting drive group 65 move upward out of the precast hollow pipe pile 1, and the sealing sleeve 42 moves upward out of the precast hollow pipe pile 1 along with the hollow connecting sleeve 68 and the support ring 60, thereby opening the discharge hole 40.

[0057] Afterwards, dry-hard concrete is filled into the precast hollow pipe pile 1. When the dry-hard concrete is continuously tamped by the column hammer 8, some of the dry-hard concrete moves to the outside of the tamping enlarged head steel cylinder 4 through the discharge hole 40 and squeezes the soil outside the tamping enlarged head steel cylinder 4. The remaining dry-hard concrete spreads to the bottom and circumference of the tamping enlarged head steel cylinder 4. The column hammer 8 tamps the dry-hard concrete to the bottom of the precast hollow pipe pile 1, forming the tamping enlarged head carrier 9 at the bottom of the pile. At this time, the tamping enlarged head carrier 9 at the bottom of the pile is formed by the tamping enlarged head steel cylinder 4 and the dry-hard concrete filling and wrapping its inner and outer walls, which further improves the overall firmness of the precast hollow pipe pile 1.

[0058] See Figure 3 and Figure 10The lifting drive assembly 65 includes a main steel wire rope 650 that slides up and down and is installed on the top of a hollow connecting sleeve 68. The side wall of the hollow connecting sleeve 68 has through holes 651 that are evenly arranged along its circumference and correspond one-to-one with the sliding components 64. A branch steel wire rope 652 is fixedly installed on the top of the sliding component 64. The other end of the branch steel wire rope 652 passes through the corresponding through hole 651 and is connected to the main steel wire rope 650. A friction-reducing guide wheel assembly is installed in the through hole 651. An elastic reset assembly is installed between the inner ring surface of the support ring 60 and the middle part of the pile bottom steel plate 61 and the corresponding sliding component 64.

[0059] After the precast hollow pipe pile 1 and its bottom tamped enlarged head steel cylinder 4 sink to the design elevation, the main wire rope 650 is pulled by the drive source (such as a winding machine). The main wire rope 650 drives the sliding component 64 connected to it to move out of the corresponding annular groove 5 through the branch wire rope 652. The sliding component 64 disengages from the corresponding annular groove 5. Then the main wire rope 650 continues to move upward and drives the pile bottom steel plate 61, support ring 60 and hollow connecting sleeve 68 to move upward out of the precast hollow pipe pile 1, thereby opening the bottom of the tamped enlarged head steel cylinder 4.

[0060] See Figure 10 and Figure 12 The friction-reducing guide wheel assembly includes two symmetrically arranged limiting guide wheels 670. The two limiting guide wheels 670 are rotatably connected to the upper and lower sides of the through hole 651 through the mounting base 671, respectively. The branch wire rope 652 is wound around the corresponding limiting guide wheel 670. The limiting guide wheel 670 is used to reduce the friction between the through hole 651 and the branch wire rope 652 and the wear of the branch wire rope 652, thereby extending the service life of the branch wire rope 652.

[0061] See Figure 10 and Figure 11 The elastic reset assembly includes an L-shaped plate 660 whose horizontal end is connected to the sliding assembly 64. After the L-shaped plate 660 passes through the guide groove 63, the vertical section of the L-shaped plate 660 is connected to the inner ring surface of the corresponding support ring 60 or the lower inner wall of the hollow connecting sleeve 68 through a reset spring 661.

[0062] In the initial state, the sliding component 64 is inserted into the corresponding annular groove 5 under the elastic force of the return spring 661; when it is necessary for the sliding component 64 to disengage from the annular groove 5, the branch wire rope 652 pulls the sliding component 64 to move, and the sliding component 64 pulls the return spring 661 to extend through the L-shaped plate 660 until the sliding component 64 disengages from the annular groove 5.

[0063] See Figures 1-10The present invention also provides a construction method for prestressed pipe pile in-hole rammed and expanded composite pile, including the following steps: S1, construction preparation: prepare and inspect the construction machinery, instruments, equipment, tools and precast hollow pipe pile 1.

[0064] S2, Long spiral pre-drilling: According to the design route, a 300mm long φ6mm steel bar is driven into the center of the pile position for positioning; after the pile position is positioned, the long spiral drilling machine is smoothly positioned and centered, the verticality of the drill rod is checked and adjusted, and then the drilling operation is carried out by the long spiral drilling machine. After drilling to the design elevation, the long spiral drilling machine is removed and moved away to obtain the required pile hole 11.

[0065] S3, Cleaning the inner wall of the pile hole: Clean the pile hole 11 using the existing cleaning device. After cleaning, inspect and accept the diameter and vertical flatness of the pile hole 11.

[0066] S4, Pipe pile bottom sealing: When the precast hollow pipe pile 1 drives the tamping enlarged head steel cylinder 4 to sink to the bottom of the pile hole 11, the sliding component 64 on the pile bottom sealing device 6 is inserted into the corresponding annular groove 5. At this time, the pile bottom steel plate 61 and the support ring 60 are locked by vertical displacement, and the pile bottom steel plate 61 seals the bottom of the tamping enlarged head steel cylinder 4.

[0067] S5, Static pressure pile driving: The precast hollow pipe pile 1 and the tamped enlarged head steel cylinder 4 below it are lifted and fed into the pile using the existing special crane. After the precast hollow pipe pile 1 and the tamped enlarged head steel cylinder 4 below it are transported to the vicinity of the existing pile driver, the pile driver drives the precast hollow pipe pile 1 and the tamped enlarged head steel cylinder 4 and presses the precast hollow pipe pile 1 and the tamped enlarged head steel cylinder 4 into the pile hole 11, pressing the tamped enlarged head steel cylinder 4 at the lower end of the precast hollow pipe pile 1 to the design elevation.

[0068] S6, Bottom of the pipe pile opens: After the precast hollow pipe pile 1 and its bottom tamping enlarged head steel cylinder 4 sink to the design elevation, the lifting drive group 65 on the pile bottom sealing device 6 is driven by the drive source to pull the sliding component 64 to move and disengage from the corresponding annular groove 5. Then, the pile bottom steel plate 61, support ring 60 and lifting drive group 65 are moved upward out of the precast hollow pipe pile 1, thereby opening the bottom of the tamping enlarged head steel cylinder 4.

[0069] S7, Column hammer filling and compaction: Filling material is introduced from the upper inlet of the precast hollow pipe pile 1, and then the column hammer 8 performs free fall compaction of the filling material until the compaction meets the requirements; then the column hammer 8 is lifted to fill dry hard concrete, and the dry hard concrete is continued to be compacted through the column hammer 8 to the bottom of the precast hollow pipe pile 1 until the compacted enlarged head carrier 9 at the bottom of the pile is formed.

[0070] S8, Installation of the core-filled steel cage: First, lift the column hammer 8 to the outside of the precast hollow pipe pile 1, then insert the core-filled steel cage 2 into the precast hollow pipe pile 1 until the bottom of the core-filled steel cage 2 contacts the top of the compacted enlarged head carrier 9 at the bottom of the pile. At this time, the plug 7 at the lower end of the core-filled steel cage 2 is inserted into the annular groove 5 opened in the inner wall of the connecting sleeve 3 to limit and lock the core-filled steel cage 2.

[0071] S9, Installation of pile cap reinforcement and formwork: A layer of graded crushed stone about 10cm thick is laid around the upper end of the precast hollow pipe pile 1 and compacted. Then the pile cap reinforcement is tied and connected to the core filling steel cage 2 inside the precast hollow pipe pile 1, ensuring that the precast hollow pipe pile 1 extends 5cm into the pile cap reinforcement. Finally, the pile cap side formwork 10 is installed around the pile cap reinforcement.

[0072] S10, Concrete pouring: The same grade of self-compacting concrete as the precast hollow pipe pile 1 is used for the pouring of the core filling steel cage 2 and the pile cap steel reinforcement in the precast hollow pipe pile 1.

[0073] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0074] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," "installed," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0075] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A prestressed pipe pile hole ramming expansion composite pile, characterized in that: The invention comprises a prefabricated hollow pipe pile (1), a core-filled steel cage (2), a compacting and enlarging head steel cylinder (4), a connector (7) and a compacting and enlarging head carrier (9) at the bottom of the pile. The interior of the prefabricated hollow pipe pile (1) is a hollow circular hole. A connecting sleeve (3) is installed at the bottom of the prefabricated hollow pipe pile (1) via high-strength bolts. A compacting and enlarging head steel cylinder (4) is installed at the lower end of the connecting sleeve (3) via high-strength bolts. The compacting and enlarging head steel cylinder (4) is in a circular cylindrical shape. The compacting and enlarging head steel cylinder (4) is concentric with the prefabricated hollow pipe pile (1) and has the same inner diameter as the prefabricated hollow pipe pile (1). An annular groove (5) is provided on the inner wall at the lower end of the tamping and enlarging head steel cylinder (4) and the lower end of the inner annular surface of the connecting sleeve (3). The bottom of the tamping and enlarging head steel cylinder (4) of the prefabricated hollow pipe pile (1) is sealed by a pile bottom sealing device (6) during the static pressure pile sinking operation. After the static pressure pile sinking operation of the prefabricated hollow pipe pile (1) is completed, the pile bottom sealing device (6) is moved upward to the outside of the prefabricated hollow pipe pile (1), and fillers and dry hard concrete are placed one by one in the prefabricated hollow pipe pile (1) and compacted to form a compacted enlarged head carrier (9) at the bottom end of the pile; The lower end of the core-filled steel cage (2) is provided with a connector (7) that is plugged into and matched with the annular groove (5) provided on the connecting sleeve (3); when the core-filled steel cage (2) is installed into the interior of the prefabricated hollow pipe pile (1), the connector (7) at the lower end of the core-filled steel cage (2) is inserted into the annular groove (5) provided on the inner wall of the connecting sleeve (3) to limit and lock the core-filled steel cage (2); The upper end of the core-filled steel cage (2) inside the prefabricated hollow pipe pile (1) is connected to a pile cap steel bar, and the core-filled steel cage (2) and the pile cap steel bar are poured by pouring self-compacting concrete of the same grade as the prefabricated hollow pipe pile (1), and vibrating and compacting and curing to obtain the desired prestressed pipe pile hole rammed and expanded composite pile; The pile bottom closing device (6) comprises a support ring (60) and a pile bottom steel plate (61) arranged in sequence from top to bottom, the inner ring surface of the support ring (60) and the top of the pile bottom steel plate (61) are jointly provided with a hollow connecting sleeve (68), the inner ring surface of the support ring (60) is fixedly connected to the hollow connecting sleeve (68) via a connecting strip (62), the side wall of the pile bottom steel plate (61) and the outer ring surface of the support ring (60) near the lower end are both provided with guide grooves (63) uniformly arranged along the circumference of the hollow connecting sleeve (68), the guide groove (63) is slidably connected with a sliding assembly (64) plug-fitted with a corresponding annular groove (5), and the hollow connecting sleeve (68) is provided with a pulling drive group (65) for pulling the sliding assembly (64) to slide along the guide groove (63); The side wall of the tamping and enlarging head steel cylinder (4) is provided with evenly arranged discharge holes (40), and a sealing sleeve (42) connected to the hollow connecting sleeve (68) is sleeved on the hollow connecting sleeve (68) via a bracket (41). The sealing sleeve (42) is inserted into the tamping and enlarging head steel cylinder (4) to seal the discharge holes (40), and the top of the sealing sleeve (42) is connected to the support ring (60) via a rib rod.

2. The prestressed pipe pile in-hole tamping and expansion composite pile according to claim 1, characterized in that: The lifting drive group (65) includes a main steel wire rope (650) installed on the top of a hollow connecting sleeve (68) and sliding up and down. The side wall of the hollow connecting sleeve (68) is provided with through holes (651) evenly arranged along its circumference and corresponding to the sliding components (64) one by one. A branch steel wire rope (652) is fixedly installed on the top of the sliding component (64). The other end of the branch steel wire rope (652) passes through the corresponding through hole (651) and is connected to the main steel wire rope (650). A friction-reducing guide wheel assembly is installed in the through hole (651). Elastic reset assemblies are installed between the inner ring surface of the support ring (60) and the middle part of the pile bottom steel plate (61) and the corresponding sliding component (64).

3. The prestressed pipe pile in-hole tamping and expansion composite pile according to claim 2, characterized in that: The friction-reducing guide wheel assembly comprises two position-limiting guide wheels (670) which are symmetrically arranged in an upper and lower manner. The two position-limiting guide wheels (670) are rotatably connected to the upper and lower sides of the through hole (651) respectively through mounting seats (671).

4. The prestressed pipe pile in-hole tamping and expansion composite pile according to claim 2, characterized in that: The elastic reset assembly comprises an L-shaped plate (660) whose horizontal section end is connected to the sliding assembly (64); after the L-shaped plate (660) passes through the guide slide groove (63), the vertical section of the L-shaped plate (660) is connected to the inner ring surface of the corresponding support ring (60) or the inner wall of the lower end of the hollow connecting sleeve (68) via a reset spring (661).

5. The prestressed pipe pile in-hole ramming and expansion composite pile according to claim 1, characterized in that: The plug-in connector (7) is a plug-in steel bar obliquely installed at the bottom of a circle of steel bars located on the outer circle of the core-filled steel bar cage (2).

6. The construction method of a prestressed pipe pile hole tamping and expansion composite pile according to claim 4 comprises the following steps: S1, construction preparation: prepare and inspect construction machinery, instruments, equipment, tools and prefabricated hollow pipe piles (1); S2, long spiral hole drilling: according to the design route, the long spiral drilling machine performs drilling operation, and after drilling to the design elevation, the long spiral drilling machine is removed and removed to obtain the required pile hole (11); S3, cleaning the inner wall of the pile hole: cleaning the pile hole (11), and after the cleaning is completed, testing and accepting the diameter of the pile hole (11) and the vertical flatness of the pile hole (11); S4, pipe pile bottom sealing: when the prefabricated hollow pipe pile (1) drives the tamping and enlarged head steel cylinder (4) to sink to the bottom of the pile hole (11), the sliding assembly (64) on the pile bottom sealing device (6) is inserted into the corresponding annular groove (5), and at this time, the pile bottom steel plate (61) and the support ring (60) are locked by moving up and down, and the pile bottom steel plate (61) seals the bottom of the tamping and enlarged head steel cylinder (4); S5, static pressure pile sinking: the prefabricated hollow pipe pile (1) and the tamping enlarged head steel cylinder (4) are pressed into the pile hole (11) by a pile driver, and the tamping enlarged head steel cylinder (4) at the lower end of the prefabricated hollow pipe pile (1) is pressed to the designed elevation; S6, opening the bottom of the pipe pile: when the prefabricated hollow pipe pile (1) and the compaction enlarged head steel cylinder (4) at the bottom thereof sink to the designed elevation, the driving source drives the lifting drive group (65) on the pile bottom closing device (6) to pull the sliding assembly (64) to move and disengage from the corresponding annular groove (5), and then drives the pile bottom steel plate (61), the support ring (60) and the lifting drive group (65) to move upward out of the prefabricated hollow pipe pile (1), thereby opening the bottom of the compaction enlarged head steel cylinder (4); S7, column hammer filling tamping: filling is carried out from the upper end inlet of the prefabricated hollow pipe pile (1), and then the column hammer (8) performs free fall to tamping the filling material until the compaction state meets the requirements; then the column hammer (8) is lifted to fill the dry hard concrete, and the column hammer (8) continues to tamping the dry hard concrete to the bottom of the prefabricated hollow pipe pile (1) until a compaction enlarged head carrier (9) is formed at the bottom of the pile; S8, installation of the core-filled steel cage: first, lift the column hammer (8) to the outside of the prefabricated hollow pipe pile (1), and then insert the core-filled steel cage (2) into the prefabricated hollow pipe pile (1) until the bottom of the core-filled steel cage (2) contacts the top of the tamping enlarged head carrier (9) at the bottom of the pile. At this time, the connector (7) at the lower end of the core-filled steel cage (2) is inserted into the annular groove (5) provided on the inner wall of the connecting sleeve (3) to limit and lock the core-filled steel cage (2); S9, installation of pile cap reinforcement and formwork: a layer of graded crushed stone cushion is laid around the upper end of the prefabricated hollow pipe pile (1) and compacted; then the pile cap reinforcement is tied and connected to the core-filled reinforcement cage (2) inside the prefabricated hollow pipe pile (1), and the prefabricated hollow pipe pile (1) is ensured to extend 5 cm into the pile cap reinforcement; finally, the pile cap side formwork (10) is installed around the pile cap reinforcement; S10, concrete pouring: using self-compacting concrete of the same grade as the prefabricated hollow pipe pile (1) to pour the core-filling steel cage (2) in the prefabricated hollow pipe pile (1) and the pile cap steel bars.

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