A core-pulling hollow pile and a connecting composite pile

Abstract

This utility model discloses a core-pulling hollow pile, comprising a pile body made of concrete, the pile body being divided into a hollow section and a solid section; the hollow section having a core-pulling hole column extending along the length of the pile body from the corresponding end face, ensuring that the concrete in the hollow section is radially free of stratification; the hole wall of the core-pulling hole column maintains the shape of a pre-set hole column defined by the outer wall of a pre-embedded core-pulling tube; and a reinforcing cage embedded in the pile body, the reinforcing cage covering both the hollow and solid sections within the pile body. This utility model also discloses a connected composite pile. The beneficial effects of this utility model are that it avoids concrete stratification, ensures stable hole wall shape and uniform material distribution, eliminates stress concentration on the outer wall, and improves the overall bearing capacity, construction reliability, and process efficiency of the pile body.

Description

Technical Field

[0001] This utility model relates to a core-extracting hollow pile and a connecting composite pile, and relates to the technical field of precast piles. Background Technology

[0002] Traditional hollow pile manufacturing often employs centrifugal processing, which uses high-speed rotation to centrifuge concrete within a mold to create internal cavities. However, this process has significant drawbacks: under centrifugal force, the concrete undergoes radial stratification due to differences in material density, forming a mortar layer, a small-particle coarse aggregate layer, and a large-particle coarse aggregate layer from the inside out. The inner mortar layer, due to its low strength and poor crack resistance, results in a weak hollow pile borehole wall structure, making it prone to collapse or deformation during construction or under load, severely impacting the overall load-bearing capacity of the pile. The accumulation of large-particle coarse aggregate on the outer layer causes stress concentration on the pile's outer wall, easily leading to localized cracks or even pile bursting during hammering or static pressure during construction, significantly increasing construction risks and costs. Although existing technologies attempt to alleviate the stratification problem by adjusting the concrete mix ratio or optimizing centrifugal parameters, they cannot fundamentally achieve a balance between material uniformity and borehole wall integrity, resulting in long-term limitations on the load-bearing capacity, durability, and construction reliability of hollow piles. Utility Model Content

[0003] The purpose of this invention is to provide a core-extracting hollow pile and a connecting composite pile, which avoids concrete delamination, ensures stable hole wall shape and uniform material distribution, eliminates stress concentration on the outer wall, and improves the overall bearing capacity, construction reliability and process efficiency of the pile.

[0004] This utility model is achieved through the following technical solution.

[0005] A hollow pile includes a pile body made of concrete, the pile body being divided into a hollow section and a solid section; the hollow section has a core-pulling column extending along the length direction of the pile body from the corresponding end face of the pile body, such that the concrete of the hollow section is not layered radially; the wall of the core-pulling column maintains the shape of a preset core-pulling column defined by the outer wall of a pre-embedded core-pulling tube. And a steel cage embedded in the pile body, wherein the coverage area of ​​the steel cage in the pile body includes the hollow section and the solid section.

[0006] As a further improvement of this utility model, the central axis of the core-pulling column and the central axis of the pile body are coaxially arranged.

[0007] As a further improvement of this utility model, the pile body is rectangular and the core-pulling hole column is cylindrical.

[0008] As a further improvement of this utility model, the reinforcing cage includes a plurality of peripheral prestressed steel bars extending along the length of the pile and distributed circumferentially, and peripheral stirrups clamping and binding the plurality of peripheral prestressed steel bars together; the peripheral prestressed steel bars extend from one end face of the pile to the other end face, and the peripheral prestressed steel bars have a plurality of connection nodes along their length direction that are connected to the peripheral stirrups.

[0009] As a further improvement of this utility model, a plurality of the peripheral prestressed steel bars are arranged at equal intervals along the edge of the pile body on the cross section, and one of the peripheral prestressed steel bars is arranged at each of the four corners.

[0010] As a further improvement of this utility model, at least one outer hoop is provided, and the outer hoop extends spirally along the length of the pile body and clamps onto multiple outer prestressed steel bars.

[0011] As a further improvement of this utility model, the peripheral prestressed steel bars and the peripheral stirrups are welded at each connection node.

[0012] As a further improvement of this utility model, the reinforcing cage further includes a plurality of inner prestressed steel bars extending along the length of the pile and distributed circumferentially, and inner hoop bars clamping and binding the plurality of inner prestressed steel bars together; the plurality of inner prestressed steel bars are located within the inner perimeter of the plurality of outer prestressed steel bars, and extend from the end face of the corresponding solid section of the pile to the interface between the solid section and the hollow section, and the inner prestressed steel bars have a plurality of connection nodes along their length that connect with the inner hoop bars.

[0013] As a further improvement of this utility model, a plurality of the inner prestressed steel bars are arranged around the center point on the cross section of the pile body, and two adjacent inner prestressed steel bars are spaced at equal intervals.

[0014] As a further improvement of this utility model, at least one inner hoop is provided, and the inner hoop extends spirally along the length of the pile body and hugs the plurality of inner prestressed steel bars.

[0015] As a further improvement of this utility model, the inner prestressed steel bars and the inner circumference are welded together at each connection node.

[0016] As a further improvement of this utility model, the inner prestressed steel bars and the inner stirrups are tied together at some connection nodes and welded together at other connection nodes.

[0017] As a further improvement of this utility model, the inner prestressed steel bars and the inner stirrups are connected by briquettes, galvanized iron wires or cold-drawn low-carbon steel wires at some connection nodes.

[0018] As a further improvement of this utility model, the peripheral prestressed steel bars are provided with a reinforced zone, an unreinforced zone, and a reinforced zone in sequence from one end to the other along the axial direction. The axial distance between two adjacent connection nodes of the peripheral prestressed steel bars in the reinforced zone is smaller than the axial distance between two adjacent connection nodes in the unreinforced zone.

[0019] As a further improvement of this utility model, one of the reinforced zones of the peripheral prestressed steel bars at least covers a portion of the corresponding solid segment of the peripheral prestressed steel bars.

[0020] As a further improvement of this utility model, the boundary between the reinforced and unreinforced zones of the peripheral prestressed steel bars corresponds to the interface between the solid and hollow sections of the pile.

[0021] As a further improvement of this utility model, the boundary between the reinforced and unreinforced zones of the peripheral prestressed steel bars is located in the hollow section of the pile body.

[0022] As a further improvement of this utility model, the axial spacing between any two adjacent connection nodes of the inner prestressed steel bars is the same.

[0023] As a further improvement of this utility model, the axial spacing between any two adjacent connection nodes of the inner prestressed steel bars is the same as that between any two adjacent connection nodes of the outer prestressed steel bars in the solid section.

[0024] As a further improvement of this utility model, the solid section of the pile body is provided with a positioning plate near the boundary between the solid section and the hollow section, and the positioning plate is fixedly connected to the ends of the multiple inner prestressed steel bars; the inner end of the pre-embedded core-pulling tube is an open end, and the core-pulling hole column is defined by the core-pulling tube and the positioning plate.

[0025] As a further improvement of this utility model, the inner end of the pre-embedded core-pulling tube is a closed end, and the core-pulling hole column is defined by the core-pulling tube.

[0026] As a further improvement of this utility model, one end of the inner prestressed steel bar corresponding to the positioning plate has a radially extended fixing part, and the fixing part is welded to the positioning plate.

[0027] As a further improvement of this utility model, the end of the prestressed steel bar is provided with an embedded sleeve with an open end exposed on the end face of the pile body. The open end of the embedded sleeve is exposed on the end face of the pile body, and its inner wall has threads for connecting and assembling spring clips or insert rods through threads.

[0028] As a further improvement of this utility model, the end of the peripheral prestressed steel bar is provided with an embedded sleeve with an open end exposed on the end face of the pile body. The open end of the embedded sleeve is exposed on the end face of the pile body, and its inner wall has threads for assembling a limiting sleeve or a plug rod through threaded connection.

[0029] As a further improvement of this utility model, the pre-embedded sleeve has an installation hole at one end of the pile body that allows the prestressed steel bar to pass through, and the end of the prestressed steel bar has a locking part located inside the pre-embedded sleeve and unable to pass through the installation hole.

[0030] As a further improvement of this utility model, the outer port of the pre-embedded sleeve has a radially protruding flange, which is used to reduce prestress loss during the tensioning process of the pile body.

[0031] As a further improvement of this utility model, the surface of the prestressed steel bar has a recessed anti-torsion groove, which extends spirally along the axial direction of the prestressed steel bar and covers its surface.

[0032] As a further improvement of this utility model, the length of the solid section accounts for 3 / 100 to 1 / 2 of the length of the pile body.

[0033] A connecting composite pile includes at least two hollow core piles connected at their ends by spring clips and insert rods.

[0034] As a further improvement of this utility model, the end connection gap of any two core-pulled hollow piles of the connecting composite pile is filled with epoxy resin.

[0035] As a further improvement of this utility model, the side of the connecting composite pile is fitted with a sleeve at the connection point of any two core-pulled hollow piles.

[0036] The beneficial effects of this utility model are: The core-extracting column of the pile is formed using a core-extracting tube and a core-extracting process. During the preparation of the hollow pile, the core-extracting tube is pre-embedded, then concrete is poured in. After the pile body is formed, the core-extracting tube is extracted, thus forming the core-extracting column. Therefore, compared to existing technologies that form the column through centrifugal processing, the pile in this embodiment has no radial stratification of the concrete in the hollow section, maintaining a uniform material distribution and eliminating stratification. This improves the overall structural strength and stability of the pile. Because the material distribution is uniform, it avoids stress concentration and increased pile burst rate caused by the accumulation of large coarse aggregate on the outer wall of the pile. The core-extracting column's wall maintains the pre-defined shape of the column defined by the pre-embedded core-extracting tube, avoiding the problem of easy collapse when the mortar layer serves as the wall. This ensures the stability of the column shape, reduces the risk of collapse due to weak wall thickness during construction, and ensures the ultimate bearing capacity of the pile. Attached Figure Description

[0037] The preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings to help understand the purpose and advantages of this utility model, wherein: Figure 1 This is a cross-sectional schematic diagram of a core-extracting hollow pile; Figure 2 This is a schematic diagram of the steel reinforcement cage. Figure 3 This is a partially enlarged schematic diagram of the reinforcing cage; Figure 4 This is a schematic diagram of the inner prestressed steel reinforcement and positioning plate; Figure 5 This is a schematic diagram of a hollow core pile and a core-pulling tube. Figure 6 This is a partial connection diagram of the composite piles; Figure 7 This is a cross-sectional view of a hollow pile with core extraction under one connection method. Figure 8 This is a cross-sectional view of a hollow pile with a core-pulling mechanism under another connection method. Figure 9 This is a schematic diagram of prestressed steel bars. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0039] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the construction shown in the accompanying drawings. The terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively. These are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive.

[0040] Implementation Case 1: A type of hollow pile with core extraction, referring to Figures 1-8 The pile body 1 has a rectangular cross-section, making its overall structure rectangular. A core-pulling column h extending along the length of the pile body 1 is provided at the center of one end of the pile body 1, so that the pile body 1 is divided into a solid section 11 and a hollow section 12 along its length. The central axis of the core-pulling column h and the central axis of the pile body 1 are the same axis. Setting the core-pulling column can reduce the self-weight and save materials on the one hand, and increase the surface area of ​​the pile body 1 on the other hand, thereby improving the side friction resistance and bearing capacity.

[0041] In this embodiment, the core-extracting column h of pile body 1 is formed using a core-extracting tube 3 and a core-extracting process. During the preparation of the hollow pile, the core-extracting tube 3 is pre-embedded and then concrete is poured in. After the pile body 1 is formed, the core-extracting tube 3 is extracted to form the core-extracting column h. Therefore, compared with the existing technology that forms the core column through centrifugal process, the concrete in the hollow section of pile body 1 in this embodiment is not stratified radially, which can maintain the uniform distribution of materials and eliminate the stratification phenomenon, thereby improving the overall structural strength and stability of pile body 1. Because the material distribution of pile body 1 is uniform, it can avoid the problem of stress concentration and increased pile burst rate caused by the accumulation of large coarse aggregate on the outer wall of the pile body. The hole wall of the core-extracting column h maintains the shape of the preset core column defined by the outer wall of the pre-embedded core-extracting tube 3, avoiding the problem of easy collapse when the mortar layer is used as the hole wall, ensuring the stability of the core column shape, reducing the risk of hole collapse due to weak hole wall during construction, and ensuring the ultimate bearing capacity of pile body 1.

[0042] The hollow pile in this embodiment also includes a steel cage embedded in the pile body 1. The steel cage covers the hollow section 12 and the solid section 11 within the pile body 1.

[0043] In this embodiment, the reinforcing cage includes multiple peripheral prestressed steel bars 211 extending along the length of the pile body 1 and distributed circumferentially, and peripheral stirrups 221 that clamp and bind the peripheral prestressed steel bars 211 together. The peripheral prestressed steel bars 211 extend from one end face of the pile body 1 to the other end face, i.e., penetrating the solid section 11 and the hollow section 12. Distributed in the peripheral areas of the solid section 11 and the hollow section 12, the peripheral prestressed steel bars 211 form a circumferential constraint on the concrete by applying prestress. This layout enhances the bending stiffness of the pile body, especially under horizontal loads such as wind force and seismic force, effectively resisting the tensile stress generated by bending moment. The peripheral stirrups 221 fix the position of the main reinforcement bars, preventing displacement of the reinforcement bars during construction or under stress, maintaining the geometry of the reinforcing cage, enhancing the shear resistance of the pile body, constraining concrete deformation, and improving overall torsional performance. The peripheral prestressed steel bars 211 have multiple connection nodes along their length that connect to the peripheral stirrups 221.

[0044] In this embodiment, multiple peripheral prestressed steel bars 211 are arranged at equal intervals along the edge of the pile body 1 cross section, with one peripheral prestressed steel bar 211 corresponding to each of the four corners. This arrangement, by distributing the peripheral prestressed steel bars 211 at equal intervals along the edge of the cross section and concentrating them at the four corners, can form a uniform circumferential prestress within the pile body 1, effectively improving the bending stiffness and crack resistance of the pile. The peripheral prestressed steel bars 211 at the four corners can significantly enhance the local compressive strength of the pile body 1 under bending or torsion, preventing concrete cracking caused by stress concentration at the corners.

[0045] In this embodiment, at least one outer stirrup 221 is provided, and the outer stirrup 221 extends spirally along the length of the pile 1 and clamps onto the multiple outer prestressed steel bars 211. The spirally extended outer stress stirrup 221 can circumferentially restrain the lateral deformation of the core concrete, forming a triaxial stress state, which significantly improves the compressive strength and crack resistance of the pile 1.

[0046] In this implementation case, the outer prestressed steel bars 211 and the outer stirrups 221 are welded at each connection node. The advantages of using welded connections include: high strength and integrity, as welding forms a metallurgical bond between the steel bars, resulting in a joint strength close to that of the parent material, effectively transferring prestress and improving the overall structural integrity; economy, as no lap length is required, saving steel bar usage, especially suitable for large-diameter steel bars; mature technology, simple construction and wide applicability, adaptable to complex pile types and connections of steel bars of different specifications; high construction efficiency, as mechanized operations (such as arc welding) can achieve rapid connections and shorten the construction period.

[0047] In some implementations, the reinforcing cage only includes the outer prestressed steel bars 211 and the outer stirrups 221, and no other reinforcing cage is provided for the part of the solid section 11 corresponding to the outer prestressed steel bars 211.

[0048] In some embodiments, the reinforcing cage further includes a plurality of inner prestressed steel bars 212 extending along the length of the pile body 1 and distributed circumferentially, and inner stirrups 222 clamping and binding the plurality of inner prestressed steel bars 212 together; the plurality of inner prestressed steel bars 212 are located within the plurality of outer prestressed steel bars 211 and extend from the end face of the solid section 11 of the pile body 1 to the interface between the solid section 11 and the hollow section 12, and the inner prestressed steel bars 212 have a plurality of connection nodes along their length direction that are connected to the inner stirrups 222.

[0049] In this implementation example, the outer prestressed steel bars 211 and the inner prestressed steel bars 212 constitute the prestressed steel bars 21 of the steel cage.

[0050] In this embodiment, multiple inner prestressed steel bars 212 are arranged around the center point of the pile body 1 on its cross-section, with adjacent inner prestressed steel bars 212 being equally spaced. This arrangement, by placing the inner prestressed steel bars 212 at equal intervals around the center point in the inner region, can form a uniformly distributed radial prestress in the core area of ​​the pile body 1, significantly improving the compressive and shear resistance of the pile. The equidistant arrangement of adjacent steel bars avoids local stress concentration and enhances the integrity of the pile body 1 when subjected to vertical loads. Especially in critical areas such as the pile top or pull-out joints, the inner prestressed steel bars 212 effectively restrain the lateral deformation of the concrete through synergistic action, reducing crack formation.

[0051] In this embodiment, the inner hoop 222 and the outer hoop 221 have the same structure, and at least one is provided. The inner hoop 222 extends spirally along the length of the pile body 1 and is clamped onto multiple inner prestressed steel bars 212.

[0052] In some implementations, the inner prestressed steel bars 212 and the inner circumference are welded together at each connection node.

[0053] In other implementations, the inner prestressed steel bars 212 and inner stirrups 222 are lapped together at some connection nodes and welded together at others. The advantages of lapped connections are flexible and simple construction, requiring no specialized equipment or high-temperature operation, and strong adaptability. By fixing the steel bar nodes with metal wire, their position can be quickly adjusted, making them particularly suitable for complex nodes or temporary on-site reinforcement; there is no heat impact, avoiding potential damage to the steel bar performance that welding might cause; and they have low requirements for the construction environment, allowing operation in damp and confined spaces. Furthermore, lapping reduces material waste, allows for controllable lap lengths, facilitates integration with welding, and balances efficiency and economy, making it suitable for small to medium-sized projects or non-critical load-bearing components.

[0054] In this implementation case, the prestressed steel bars 21 and stirrups 22 are tied together with annealed wire, galvanized iron wire or cold-drawn low-carbon steel wire. All of these materials have good corrosion resistance and durability, and the material cost is low.

[0055] In this implementation case, the outer prestressed steel bars 211 are arranged axially from one end to the other in a reinforced zone s1, an unreinforced zone s2, and another reinforced zone s1. The axial spacing between two adjacent connection nodes of the outer prestressed steel bars 211 in the reinforced zone s1 is smaller than the axial spacing between two adjacent connection nodes in the unreinforced zone s2. The reinforced zone s1 significantly improves the shear resistance at the ends of the structure by reducing the axial spacing of the stirrups 22. Under seismic or impact loads, the dense steel bars in the reinforced zone s1 can effectively disperse shear stress and prevent concrete cracking. The unreinforced zone s2 uses stirrups 22 with a larger spacing, which reduces material usage while meeting overall stiffness requirements. The reinforced zones s1 at both ends are used to reinforce areas of stress concentration. The segmented arrangement of the reinforced zone s1 and the unreinforced zone s2 takes into account both construction convenience and cost control, reduces on-site adjustments, and improves construction efficiency.

[0056] In this implementation case, one of the reinforced zones s1 of the outer prestressed steel bars 211, that is, the reinforced zone s1 corresponding to the solid section 11, covers at least the part of the outer prestressed steel bars 211 corresponding to the solid section 11. In other words, all the outer prestressed steel bars 211 within the solid section 11 are reinforced zones s1, which can improve the shear and pull-out resistance of key nodes.

[0057] In some implementations, the boundary between the reinforced zone s1 and the unreinforced zone s2 of the outer prestressed steel bar 211 corresponds to the boundary between the solid section 11 and the hollow section 12 of the pile body 1, that is, the part of the hollow section 12 close to the solid section 11 is the unreinforced zone s2.

[0058] In some other implementations, the boundary between one of the reinforced zones s1 and the unreinforced zone s2 of the outer prestressed steel reinforcement 211 is located in the hollow section 12 of the pile body 1.

[0059] In this implementation, the axial spacing between any two adjacent connection nodes of the inner prestressed steel bars 212 is the same. This equidistant arrangement enables the inner prestressed steel bars 212 to form a uniform and continuous prestress field inside the pile body 1, effectively improving the compressive and shear bearing capacity of the core area. The uniform axial spacing avoids stress abrupt changes and ensures that the load is uniformly transmitted along the longitudinal direction. Especially when subjected to eccentric loads or lateral earth pressure, it can suppress the lateral expansion deformation of concrete and reduce the risk of local cracking.

[0060] In this implementation case, the axial spacing between any two adjacent connection nodes of the inner prestressed steel bars 212 is the same as the axial spacing between any two adjacent connection nodes of the outer prestressed steel bars 211 in the solid section 11. This uniform spacing design enables the inner and outer prestressed systems to form a coherent constraint network, which not only ensures the synergistic effect of the outer bending resistance and the inner compressive resistance, but also enhances the hoop effect of the concrete core area through the regular node layout, thereby enhancing the adaptability of the solid section 11 to impact loads or eccentric bending moments.

[0061] In some implementations, for the inner prestressed steel bars 212, a positioning plate 23 is provided at the location near the boundary between the solid section 11 and the hollow section 12 of the pile body 1. The positioning plate 23 is fixedly connected to the ends of multiple inner prestressed steel bars 212. In this case, the inner end of the pre-embedded core-pulling tube 3 is an open end, and the core-pulling hole column h is defined by the core-pulling tube 3 and the positioning plate 23. By setting the positioning plate 23 inside the pile body 1 and fixing it to the inner prestressed steel bars 212, the displacement of the ends of the inner prestressed steel bars 212 can be effectively constrained, ensuring the continuity and accuracy of prestress transmission. The positioning plate 23 forms a rigid node through mechanical anchoring, enhancing the local shear resistance of the concrete at the boundary, preventing stress concentration caused by the sudden change in stiffness between the hollow section 12 and the solid section 11, and suppressing the positional displacement of the inner prestressed steel bars 212 during the pouring or pile driving process, thus ensuring the stability of the coordinated deformation of the inner and outer steel bars when the pile body 1 is subjected to bending.

[0062] In some other implementations, the inner end of the pre-embedded core-pulling tube 3 is a closed end, and the core-pulling hole column h is defined by the core-pulling tube 3. In this case, the positioning plate 23 is not required.

[0063] In this embodiment, the inner prestressed steel bar 212 has a radially extended fixing part 21b at one end corresponding to the positioning plate 23, such that the diameter of the fixing part 21b is larger than the diameter of the inner prestressed steel bar 212, and the fixing part 21b is welded to the positioning plate 23. By setting the fixing part 21b, the contact area between the inner prestressed steel bar 212 and the positioning plate 23 can be increased, and the welding surface can be expanded by welding, thereby improving the fixed connection strength between the fixing plate and the inner prestressed steel bar 212.

[0064] In this implementation example, the outer stirrups 221 and the inner stirrups 222 are arranged with the same helical direction, meaning they are both either left-handed or right-handed structures. This arrangement avoids stress interference caused by different helical directions and enhances the overall integrity of the pile.

[0065] In one implementation, refer to Figure 7 The prestressed steel bar 21 has an embedded sleeve 24 with its open end exposed on the end face of the pile body 1. The embedded sleeve 24 has threads 241 on its inner wall for connecting and assembling spring clips 41 or insert rods 42 via the threads 241. In this embodiment, the core-pulling hollow pile is assembled with other core-pulling hollow piles by inserting spring clips 41 and insert rods 42. More specifically, when connecting the ends of two core-pulling hollow piles, the insert rod 42 is inserted axially into the spring clip 41 and locked by the locking structure in the spring clip 41, thus completing the connection of the core-pulling hollow piles. By providing an embedded sleeve 24 at the end of the prestressed steel bar 21, the spring clip 41 or insert rod 42 can be assembled via threaded connection 241. This assembly can usually be performed before connection, facilitating construction.

[0066] In this embodiment, a plug is embedded at the open end of the pre-embedded sleeve 24 to seal the open end of the sleeve before assembling the spring clip 41 or the insertion rod 42. When the spring clip 41 or the insertion rod 42 is not installed, sealing the open end of the pre-embedded sleeve 24 with the plug can prevent foreign objects from entering the pre-embedded sleeve 24, thus protecting the internal environment of the pre-embedded sleeve 24, especially preventing structural damage to the thread 241 that would affect the assembly of the spring clip 41 or the insertion rod 42.

[0067] In another implementation, refer to Figure 8 The pre-embedded sleeve 24 is connected to the limiting sleeve 43 or the insertion rod 42 via thread 241. The two hollow core piles are assembled by connecting the limiting sleeve 43 and the insertion rod 42; this connection method is a seamless connection. For detailed technical solutions, please refer to the applicant's online application: Publication number CN220977978U, patent title "A Seamless Connector".

[0068] In both of these implementation methods, refer to Figure 7 and Figure 8 The pre-embedded sleeve 24 has an installation hole 242 at one end inside the pile body 1, which allows the prestressed steel bar 21 to pass through. The end of the prestressed steel bar 21 has a locking part 21a located inside the pre-embedded sleeve 24 and unable to pass through the installation hole 242. The locking part 21a can prevent the pre-embedded sleeve 24 and the prestressed steel bar 21 from separating. In specific implementation, the prestressed steel bar 21 can be passed through the installation hole 242 first, and then the locking part 21a can be welded to the end of the prestressed steel bar 21, thereby achieving the locking of the prestressed steel bar 21 and the pre-embedded sleeve 24.

[0069] In both of these implementation methods, refer to Figure 7 and Figure 8 The outer end of the pre-embedded sleeve 24 has a radially protruding flange 243. During the tensioning process, when the reinforcing bar retracts, the flange 243 forms local compression with the concrete, increasing the frictional resistance of the contact surface and restricting the slippage of the reinforcing bar. At the same time, the flange 243 disperses the retraction stress to a wider range of concrete, reducing stress concentration at the anchorage end and preventing local crushing or cracking of the concrete, thereby reducing losses caused by anchor deformation and prestressing tendon retraction. In addition, the flange 243 can optimize the stress transmission path, ensuring that the prestress is transmitted more evenly to the pile body 1, maintaining effective prestress, so that the flange 243 can reduce prestress loss during the tensioning process of the pile body 1.

[0070] In this implementation case, refer to Figure 9 The prestressed steel bars 21, namely the outer prestressed steel bars 211 and the inner prestressed steel bars 212, have recessed anti-torsion grooves 21c on their surfaces. The anti-torsion grooves 21c extend spirally along the axial direction of the prestressed steel bars 21 and cover their surfaces. The anti-torsion grooves 21c enhance the mechanical interlocking with the concrete, improve the bond strength between the two, thereby ensuring that the prestress is effectively transferred to the concrete structure and preventing relative slippage between the steel bars and the concrete during tensioning or stress. It also helps to form a more uniform stress distribution during the concrete hardening process and reduces local stress concentration.

[0071] In this implementation case, the length of the solid section 11 accounts for 3 / 100 to 1 / 2 of the length of the pile body 1.

[0072] Implementation Case 2: A type of connecting composite pile, referring to Figure 5 and Figure 6 It includes at least two hollow cores, as shown in Implementation Case 1, with the hollow cores connected at their ends by spring clips 41 and insert rods 42.

[0073] In this embodiment, the end connection gap of any two core-pulled hollow piles of the connecting composite pile is filled with epoxy resin 13. Filling the connection gap with epoxy resin 13 can improve the sealing performance and facilitate subsequent assembly.

[0074] In this embodiment, the side of the connecting composite pile is equipped with a sleeve 14 at the connection point of any two hollow core piles. The sleeve 14 can prevent the upper hollow core piles from being misaligned during connection.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A hollow pile with core extraction, characterized in that, The pile body (1) is made of concrete and is divided into a hollow section (12) and a solid section (11). The hollow section (12) has a core-pulling column (h) extending along the length of the pile body (1) from the end face corresponding to the pile body (1), so that the concrete of the hollow section (12) is not stratified in the radial direction. The hole wall of the core-pulling column (h) maintains the shape of the preset core-pulling column defined by the outer wall of the pre-embedded core-pulling tube (3). And a steel cage embedded in the pile body (1), the coverage area of ​​the steel cage in the pile body (1) includes the hollow section (12) and the solid section (11).

2. The hollow pile according to claim 1, characterized in that, The central axis of the core-pulling column (h) and the central axis of the pile body (1) are coaxially arranged.

3. The hollow pile according to claim 1, characterized in that, The pile body (1) is rectangular, and the core-pulling hole column (h) is cylindrical.

4. The hollow pile according to claim 1, characterized in that, The steel cage includes a plurality of peripheral prestressed steel bars (211) extending along the length of the pile body (1) and distributed circumferentially, and peripheral stirrups (221) clamping the plurality of peripheral prestressed steel bars (211) and binding them together; the peripheral prestressed steel bars (211) extend from one end face of the pile body (1) to the other end face, and the peripheral prestressed steel bars (211) have a plurality of connection nodes along their length direction that are connected to the peripheral stirrups (221).

5. The hollow pile according to claim 4, characterized in that, Multiple peripheral prestressed steel bars (211) are arranged at equal intervals along the edge of the cross section of the pile body (1), and one peripheral prestressed steel bar (211) is arranged at each of the four corners.

6. The hollow pile according to claim 4, characterized in that, At least one of the outer hoop bars (221) is provided, and the outer hoop bars (221) extend spirally along the length of the pile body (1) and hug the multiple outer prestressed steel bars (211).

7. The hollow pile according to claim 4, characterized in that, The outer prestressed steel bars (211) and the outer stirrups (221) are welded at each connection node.

8. The hollow pile according to claim 4, characterized in that, The steel cage also includes a plurality of inner prestressed steel bars (212) extending along the length of the pile body (1) and distributed circumferentially, and inner hoop bars (222) clamping the plurality of inner prestressed steel bars (212) and binding them together; the plurality of inner prestressed steel bars (212) are located within the inner perimeter of the plurality of outer prestressed steel bars (211) and extend from the end face of the solid section (11) of the pile body (1) to the interface between the solid section (11) and the hollow section (12), and the inner prestressed steel bars (212) have a plurality of connection nodes along their length that are connected to the inner hoop bars (222).

9. The hollow pile according to claim 8, characterized in that, Multiple inner prestressed steel bars (212) are arranged around the center point on the cross section of the pile body (1), and adjacent inner prestressed steel bars (212) are spaced at equal intervals.

10. The hollow pile according to claim 8, characterized in that, At least one inner hoop (222) is provided, and the inner hoop (222) extends spirally along the length of the pile body (1) and clamps onto the plurality of inner prestressed steel bars (212).

11. The hollow pile according to claim 8, characterized in that, The inner prestressed steel bars (212) and the inner circumference are welded at each connection node.

12. The hollow pile according to claim 8, characterized in that, The inner prestressed steel bars (212) and the inner stirrups (222) are tied together at some connection nodes and welded together at other connection nodes.

13. The hollow pile according to claim 12, characterized in that, The inner prestressed steel bars (212) and the inner stirrups (222) are tied together at some connection nodes by annealed wire, galvanized iron wire or cold-drawn low carbon steel wire.

14. The hollow pile according to claim 4, characterized in that, The peripheral prestressed steel bars (211) are provided with a reinforced zone (s1), an unreinforced zone (s2), and a reinforced zone (s1) in sequence from one end to the other along the axial direction. The axial distance between two adjacent connection nodes of the peripheral prestressed steel bars (211) in the reinforced zone (s1) is smaller than the axial distance between two adjacent connection nodes in the unreinforced zone (s2).

15. The hollow pile according to claim 14, characterized in that, One of the reinforced zones (s1) of the peripheral prestressed steel bars (211) covers at least a portion of the solid segment (11) corresponding to the peripheral prestressed steel bars (211).

16. The hollow pile according to claim 15, characterized in that, The boundary between the reinforced zone (s1) and the unreinforced zone (s2) of the outer prestressed steel bar (211) corresponds to the interface between the solid section (11) and the hollow section (12) of the pile body (1).

17. The hollow pile according to claim 15, characterized in that, The boundary between one of the reinforced zones (s1) and the unreinforced zone (s2) of the peripheral prestressed steel bars (211) is located in the hollow section (12) of the pile body (1).

18. The hollow pile according to claim 8, characterized in that, The axial spacing between any two adjacent connection nodes of the inner prestressed steel bars (212) is the same.

19. The hollow pile according to claim 18, characterized in that, The axial spacing between any two adjacent connection nodes of the inner prestressed steel bar (212) is the same as that between any two adjacent connection nodes of the outer prestressed steel bar (211) in the solid section (11).

20. The hollow pile according to claim 8, characterized in that, The solid section (11) of the pile body (1) is provided with a positioning plate (23) near the boundary between the solid section (11) and the hollow section (12). The positioning plate (23) and the ends of the multiple inner prestressed steel bars (212) are fixedly connected. The inner end of the pre-embedded core-pulling tube (3) is an open end, and the core-pulling hole column (h) is defined by the core-pulling tube (3) and the positioning plate (23).

21. The hollow pile according to claim 8, characterized in that, The inner end of the pre-embedded core-pulling tube (3) is a closed end, and the core-pulling hole column (h) is defined by the core-pulling tube (3).

22. The hollow pile according to claim 20, characterized in that, The inner prestressed steel bar (212) has a radially extended fixing part at one end corresponding to the positioning plate (23), and the fixing part is welded to the positioning plate (23).

23. The hollow pile according to claim 4, characterized in that, The pre-embedded sleeve (24) with its open end exposed on the end face of the pile body (1) is provided at the end of the pre-embedded sleeve (24). The open end of the pre-embedded sleeve (24) is exposed on the end face of the pile body (1), and its inner wall has threads (241) for connecting the assembly spring clip (41) or the insertion rod (42) through the threads (241).

24. The hollow pile according to claim 4, characterized in that, The end of the peripheral prestressed steel bar (211) is provided with an embedded sleeve (24) with an open end exposed on the end face of the pile body (1). The open end of the embedded sleeve (24) is exposed on the end face of the pile body (1), and its inner wall has a thread (241) for connecting the assembly limiting sleeve (43) or the insertion rod (42) through the thread (241).

25. The hollow pile according to claim 23 or 24, characterized in that, The pre-embedded sleeve (24) has an installation hole (242) at one end inside the pile body (1) that allows the prestressed steel bar to pass through, and the end of the peripheral prestressed steel bar (211) has a locking part (21a) located inside the pre-embedded sleeve (24) and unable to pass through the installation hole (242).

26. The hollow pile according to claim 23 or 24, characterized in that, The outer port of the pre-embedded sleeve (24) has a radially protruding flange (243) for reducing prestress loss during the tensioning process of the pile body (1).

27. The hollow pile according to any one of claims 4-26, characterized in that, The surface of the peripheral prestressed steel bar (211) has a recessed anti-torsion groove (21c), which extends spirally along the axial direction of the peripheral prestressed steel bar (211) and covers its surface.

28. The hollow pile according to any one of claims 8-13 and 18-22, characterized in that, The surface of the inner prestressed steel bar (212) has a recessed anti-torsion groove (21c), which extends spirally along the axial direction of the inner prestressed steel bar (212) and covers its surface.

29. The hollow pile according to any one of claims 1-26, characterized in that, The length of the solid section (11) is 3 / 100 to 1 / 2 of the length of the pile body (1).

30. A type of connecting composite pile, characterized in that, The hollow core (101) includes at least two core-pulling posts (101) connected at their ends by spring clips (41) and inserts (42), as described in any one of claims 1-29.

31. The connecting composite pile according to claim 30, characterized in that, The end connection gap of any two core-extracting hollow piles (101) of the connecting composite pile is filled with epoxy resin (13).

32. The connecting composite pile according to claim 30, characterized in that, The side of the connecting pile is fitted with a sleeve (14) at the connection point of any two core-pulling hollow piles (101).

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