A construction method for composite piles with enhanced support structures and its application

Abstract

This invention discloses a construction method for composite piles that enhance support structures and its application, relating to the field of building technology. It solves the problem of centrally positioning prestressed pipe piles in composite piles to ensure coordinated load-bearing. The construction method includes setting a positioning support frame on the surface of the pipe pile for automatic centering during pile driving, then pouring concrete to form a cast-in-place pile encasing the pipe pile, and finally connecting it to a capping beam via an integrated component to achieve overall anchoring. This method is mainly used to improve the stability and bearing capacity of deep foundation pit support structures. The invention utilizes a positioning support frame constructed by welding reinforcing bars, positioning ring bars, and an external steel mesh to the surface of the prestressed pipe pile. This support frame automatically centers the pile during driving, and a prefabricated integrated sealing and anchoring component ensures a reliable connection between the pile top and the capping beam, thereby ensuring the pipe pile is centered, shares load, and significantly enhances the overall stability and bearing capacity of the support structure.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a method for constructing composite piles with enhanced support structures and its application. Background Technology

[0002] In the field of construction engineering, especially in urban deep foundation pit engineering, pile support structures are a widely used form of underground support. To ensure the stability and reliability of the support system, cast-in-place piles (such as bored piles) are often used as the main load-bearing components, and are connected into a whole by a capping beam at the top to jointly bear the soil and water pressure. To cope with complex geological conditions and higher bearing capacity requirements, the development of composite pile technology that combines good adaptability, high strength, and economy has become an important development direction in this field.

[0003] In existing technologies, a more advanced approach is to enhance the performance of cast-in-place piles using an "internalized pipe pile" method. This involves first constructing the cast-in-place piles, and then, before the concrete has initially set, driving prestressed high-strength concrete pipe piles into them, forming a so-called "composite pile." This design aims to combine the high strength and crack resistance of the internal PHC pipe piles with the good adaptability of the external cast-in-place piles to complex geological formations, achieving a complementary effect. Specifically, this existing technical solution typically includes the following steps: First, drilling holes (dry holes or mud-walled holes) in the foundation; then, pouring the cast-in-place pile concrete; subsequently, before the concrete has solidified, pressing or driving the precast PHC pipe piles into the core of the cast-in-place pile. Finally, constructing a capping beam to connect the pile heads of the composite piles.

[0004] However, after in-depth research and practice of the aforementioned prior art solutions, the inventors of this application discovered a core technical problem: the inability to effectively guarantee the precise central positioning of the PHC pipe pile within the cast-in-place pile, leading to a significant reduction in the synergistic bearing capacity of the composite pile and affecting the overall stability of the support structure. Specifically, during pile driving, the pipe pile, lacking effective external guidance and internal support, is highly prone to deviation; consequently, the cores of the pipe pile and the cast-in-place pile do not coincide, resulting in uneven thickness of the outer concrete protective layer. The concrete at thin-walled sections is easily crushed, preventing the full utilization of the high strength advantage of the PHC pipe pile, making it difficult for the two to achieve ideal synergistic work. Simultaneously, the connection between the pile top and the capping beam is difficult to seal and anchor effectively due to the pipe pile's misalignment, posing a risk of grout leakage and further weakening the integrity of the joint. Therefore, ensuring the central position of the pipe pile within the composite pile is a key bottleneck in realizing its synergistic bearing design concept. Summary of the Invention

[0005] This invention provides a composite pile construction method for enhancing support structure and its application. The technical problem to be solved is: how to ensure the central position of the pipe pile in the composite pile to realize its collaborative bearing design concept.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: In a first aspect, the present invention provides a method for constructing composite piles to enhance a support structure. The support structure includes composite piles connected by a capping beam. The composite piles consist of internal prestressed pipe piles and externally encased dry-hole cast-in-place piles. The construction method includes the following steps: S1. Preparation steps of prestressed pipe pile positioning support frame: At least two positioning sections are set at intervals on the surface of the prestressed pipe pile. At each positioning section, multiple anchor bars are evenly inserted along the circumference of the pipe pile. A ring-shaped positioning ring bar is welded and fixed to the exposed ends of each anchor bar at the same section to form a positioning support frame. Multiple longitudinal steel bars are welded on the anchor bars at a certain distance from the outer wall of the pipe pile, and stirrups are set around the multiple longitudinal steel bars to form a steel mesh.

[0007] S2. Pile driving and grouting steps: The prestressed pipe piles processed in step S1 are driven into the pre-formed dry-hole pile holes. The outer diameter of the positioning ring reinforcement is smaller than the diameter of the pile hole to ensure that the pipe pile is centered in the pile hole. Then, concrete is poured into the pile hole to form a dry-hole cast-in-place pile that wraps the prestressed pipe pile and the steel mesh, so that the prestressed pipe pile and the dry-hole cast-in-place pile can work together to bear the load.

[0008] S3. Crown Beam Connection Steps: At the pile top, an integrated sealing and anchoring component is used to seal the pile hole of the prestressed pipe pile and anchor it to the crown beam. The integrated sealing and anchoring component has a lower sealing part that can be inserted into the pile hole and an upper anchoring part that covers the upper surface of the pile end. The upper anchoring part is pre-set with anchoring steel bars for connection with the crown beam reinforcement skeleton and has a reserved hole for the upper end of the longitudinal steel bar in step S1 to be inserted. The crown beam concrete is poured so that the upper end of the longitudinal steel bar, the anchoring steel bar of the integrated sealing and anchoring component and the space inside the reserved hole form an integral whole with the crown beam.

[0009] Furthermore, in step S1, the implantation direction of the rebar corresponds to the 3 o'clock, 6 o'clock, 9 o'clock and 12 o'clock directions of the circumference of the pipe pile, respectively.

[0010] Furthermore, the diameter of the positioning ring reinforcement is larger than the outer diameter of the prestressed pipe pile and equal to the inner diameter of the dry hole pile.

[0011] In a second aspect, the present invention provides a prestressed pipe pile positioning support frame for implementing a construction method, comprising: Multiple reinforcing bars are fixed to the outer wall of the prestressed pipe pile by means of rebar anchoring.

[0012] The annular positioning ring is welded and fixed to the exposed ends of each of the aforementioned anchor bars at the same cross section.

[0013] Longitudinal reinforcing bars are welded to the anchor bars and are spaced apart from the outer wall of the pipe pile.

[0014] Stirrups are tied or welded around the perimeter of multiple longitudinal reinforcing bars, forming a reinforcing mesh together with the longitudinal reinforcing bars.

[0015] Thirdly, the present invention provides an integrated sealing and anchoring component for implementing a construction method, which is a precast concrete component comprising: The lower sealing part is a cylinder with a diameter smaller than the inner diameter of the prestressed pipe pile, which is used to be inserted into the pile hole to achieve sealing.

[0016] The upper anchoring part is a plate-shaped body with a diameter larger than the outer diameter of the prestressed pipe pile, which is connected to the upper end of the lower sealing part and is used to cover the top of the pile.

[0017] At least one vertical anchoring steel bar is embedded in the component, with its upper end extending out of the upper surface of the upper anchoring part.

[0018] Multiple pre-drilled holes, penetrating the upper anchorage section, are positioned corresponding to the distribution of longitudinal reinforcing bars in the composite pile, and are used for inserting the upper ends of the longitudinal reinforcing bars.

[0019] Fourthly, the present invention provides a support structure formed by the construction method described above, comprising: Prestressed pipe piles.

[0020] The dry-hole cast-in-place pile encloses the prestressed pipe pile and forms a cooperative load-bearing structure with the prestressed pipe pile through the steel mesh in the positioning support frame.

[0021] The cap beam is set on top of the prestressed pipe pile.

[0022] An integrated sealing and anchoring component seals the pile hole of the prestressed pipe pile and anchors the upper end of the longitudinal steel bar 6 and its own anchoring steel bar into the cap beam.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: By welding reinforcing bars, positioning ring bars, and external steel mesh onto the surface of the prestressed pipe pile to form a positioning support frame, the support frame automatically centers during pile driving. A prefabricated integrated sealing and anchoring component is used to achieve a reliable connection between the pile top and the cap beam, thereby ensuring that the pipe pile is centered and shares the load, and significantly enhancing the overall stability and bearing capacity of the support structure. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of the composite pile in this invention.

[0025] Figure 2 This is a schematic diagram of the structure of the outer wall of the prestressed pipe pile in this invention.

[0026] Figure 3 This is a partial enlargement of the outer wall structure of the prestressed pipe pile in this invention. Figure 1 .

[0027] Figure 4 This is a partial enlargement of the outer wall structure of the prestressed pipe pile in this invention. Figure 2 .

[0028] Figure 5 This is a top view of the positioning support frame on the prestressed pipe pile in this invention.

[0029] Figure 6 This is a schematic diagram of the overall structure of the prestressed pipe pile top integrated sealing and anchoring component in this invention.

[0030] Figure 7 This is a partial enlarged view of the integrated sealing and anchoring component at the top of the prestressed pipe pile in this invention.

[0031] Figure 8 This is a top view of the integrated sealing and anchoring component in this invention.

[0032] Figure 9 This is a bottom view of the integrated sealing and anchoring component in this invention.

[0033] Figure 10 This is a schematic diagram of the connection between the prestressed pipe pile and the cap beam in this invention.

[0034] In the diagram: 1-Prestressed pipe pile, 2-Dry hole cast-in-place pile, 3-Rebar installation, 4-Positioning ring reinforcement, 5-Positioning support frame, 6-Longitudinal reinforcement, 7-Stirrups, 8-Integrated sealing and anchoring component, 9-Lower sealing part, 10-Upper anchoring part, 11-Anchoring reinforcement, 12-Reserved hole, 13-Cap beam. Detailed Implementation

[0035] In order to make the content of the present invention easier to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described.

[0036] This application addresses the core technical problem in existing composite pile construction where prestressed concrete pipe piles are difficult to accurately center within the external cast-in-place pile, leading to a decrease in synergistic bearing capacity. It proposes a composite pile construction method that enhances the support structure. The solution involves welding reinforcing bars 3, positioning ring bars 4, and an external steel mesh onto the surface of the prestressed concrete pipe pile 1 to form a positioning support frame 5. This positioning support frame 5 automatically centers the pile during driving, and a prefabricated integrated sealing and anchoring component 8 ensures a reliable connection between the pile top and the capping beam 13. This guarantees the pipe pile's centering, synergistic load-bearing, and significantly enhances the overall stability and bearing capacity of the support structure. Example 1

[0037] A method for constructing a composite pile to enhance a support structure, the support structure comprising composite piles connected by a capping beam 13, the composite piles being composed of an inner prestressed pipe pile 1 and an outer dry-hole cast-in-place pile 2; the construction method includes the following steps: S1. Preparation steps of positioning support frame 5 on prestressed pipe pile 1: At least two positioning sections are set at intervals on the surface of prestressed pipe pile 1. At each positioning section, multiple anchor bars 3 are evenly inserted along the circumference of the pipe pile. A ring-shaped positioning ring bar 4 is welded and fixed to the exposed ends of each anchor bar 3 at the same section to form a positioning support frame 5. Multiple longitudinal steel bars 6 are welded on the anchor bars 3 at a certain distance from the outer wall of the pipe pile, and stirrups 7 are set around the multiple longitudinal steel bars 6 to form a steel mesh.

[0038] Step S1 described above is the foundation and key pretreatment step for subsequent construction. Its technical essence lies in creating an "exoskeleton" structure integrated with the pipe pile. This structure has a dual function: firstly, the support frame composed of the reinforcing bars 3 and positioning ring bars 4 serves as a "navigation" mechanism for subsequent pile driving, ensuring verticality; secondly, the steel mesh composed of longitudinal reinforcing bars 6 and stirrups 7 provides a built-in stiffening skeleton for the external cast-in-place pile. This is the core structure for achieving coordinated force sharing between the pipe pile and the cast-in-place pile, elevating them from a simple physical enclosure to a robust reinforced concrete assembly.

[0039] S2. Pile driving and grouting steps: The prestressed pipe pile 1 processed in step S1 is driven into the pre-formed dry hole pile hole. The outer diameter of the positioning ring reinforcement 4 is smaller than the diameter of the pile hole to ensure that the pipe pile is located in the center of the pile hole. Then, concrete is poured into the pile hole to form a dry hole grouting pile 2 that wraps the prestressed pipe pile 1 and the steel mesh, so that the prestressed pipe pile 1 and the dry hole grouting pile 2 can work together to bear the load.

[0040] Step S2 is the core of achieving the bearing capacity of the composite pile. Its innovation lies in utilizing the positioning support frame 5 prepared in step S1 as a "centerer," automatically ensuring the ideal position of the prestressed pipe pile 1 within the cast-in-place pile. This ensures uniform stress distribution on the composite pile and eliminates the risks associated with pile misalignment. Simultaneously, concrete is poured around the steel mesh already attached to the pipe pile, integrating the three (pipe pile, steel mesh, and cast-in-place pile concrete) into a unified whole, truly achieving "synergistic bearing capacity" and significantly improving the bearing capacity and deformation resistance of the single pile.

[0041] S3, Connection Steps of Crown Beam 13: At the pile top position, an integrated sealing and anchoring component 8 is used to seal the pile hole of the prestressed pipe pile 1 and anchor it to the crown beam 13; the integrated sealing and anchoring component 8 has a lower sealing part 9 that can be inserted into the pile hole of the pipe pile, and an upper anchoring part 10 covering the upper surface of the pile end; the upper anchoring part 10 is pre-set with anchoring steel bars 11 for connection with the steel reinforcement skeleton of the crown beam 13, and is provided with a reserved hole 12 for the upper end of the longitudinal steel bar 6 in step S1 to be inserted; the concrete of the crown beam 13 is poured so that the upper end of the longitudinal steel bar 6, the anchoring steel bar 11 of the integrated sealing and anchoring component 8 and the space inside the reserved hole 12 form an integral whole with the crown beam 13.

[0042] Step S3 ensures the integrity of the top of the support structure. Its technical value lies in elevating pile head treatment from simple sealing to "integrated sealing and structural anchoring." Through specialized components, not only are the pipe pile holes effectively sealed to prevent grout leakage, but more importantly, it anchors all the longitudinal reinforcement 6 (force transmission path) from the lower composite pile and the component's own anchoring reinforcement 11 into the capping beam 13, forming a rigid node connection. This greatly enhances the stability of the support system as a whole, effectively connecting and enabling the individual piles to work together.

[0043] Furthermore, in step S1, the implantation direction of the rebar 3 corresponds to the 3 o'clock, 6 o'clock, 9 o'clock and 12 o'clock directions of the circumference of the pipe pile, respectively.

[0044] By adopting a four-point symmetrical arrangement (like a cross), the positioning ring reinforcement 4 can be evenly supported and fixed from four directions, ensuring that the constraint force on the pipe pile is balanced in all directions during the sinking process, and preventing tilting to the greatest extent. This is one of the best implementation methods to achieve precise positioning.

[0045] Furthermore, in step S1, the diameter of the positioning ring 4 is greater than the outer diameter of the prestressed pipe pile 1, and the diameter of the positioning ring 4 is equal to the inner diameter of the dry hole pile.

[0046] This is an important technical feature that ensures that the positioning support frame 5 is in proper contact with the borehole wall of the dry-hole pile during pile driving, thereby "guiding" and ensuring that the precast pipe pile is centered, thus ensuring that the outer periphery of the pipe pile is sufficiently thick to be wrapped with concrete. Example 2

[0047] A positioning support frame 5 for implementing the construction method described in Embodiment 1 for prestressed pipe pile 1 includes: Multiple reinforcing bars 3 are fixed to the outer wall of the prestressed pipe pile 1 by means of rebar anchoring 3.

[0048] The annular positioning ring 4 is welded and fixed to the exposed ends of each of the anchor bars 3 at the same cross section.

[0049] The longitudinal reinforcing bar 6 is welded to the anchor bar 3 and is spaced apart from the outer wall of the pipe pile.

[0050] The stirrups 7 are tied or welded around the periphery of the multiple longitudinal steel bars 6, and together with the longitudinal steel bars 6, they form a steel mesh.

[0051] The key component is the positioning support frame 5. This device combines the functions of "positioning" and "reinforcement cage". A stable "positioning ring" is formed by the anchor bars 3 and the positioning ring bars 4, ensuring pile driving accuracy. Meanwhile, the longitudinal reinforcing bars 6 and stirrups 7 welded to the anchor bars 3 directly constitute the load-bearing reinforcement cage for the later-stage cast-in-place pile. This integrated design avoids the cumbersome process of separately installing the locator and the reinforcement cage, and is a crucial hardware foundation for improving efficiency and ensuring quality in this technology. Example 3

[0052] A precast concrete component 8 for sealing and anchoring the pile holes of the cap beam 13, used to implement the construction method described in Embodiment 1, comprises: The lower sealing part 9 is a cylinder with a diameter smaller than the inner diameter of the prestressed pipe pile 1, which is used to be inserted into the pile hole to achieve sealing.

[0053] The upper anchoring part 10 is a plate-shaped body with a diameter larger than the outer diameter of the prestressed pipe pile 1, which is connected to the upper end of the lower sealing part 9 and is used to cover the top of the pile.

[0054] At least one vertical anchoring steel bar 11 is embedded in the component, with its upper end extending out of the upper surface of the upper anchoring part 10.

[0055] Multiple pre-drilled holes 12 penetrate the upper anchoring part 10, and their positions correspond to the distribution positions of the longitudinal steel bars 6 in the composite pile, for the upper end of the longitudinal steel bars 6 to be inserted.

[0056] The traditional "pile hole plug" has been upgraded to a multi-functional connector. The lower sealing part 9 provides physical sealing to prevent concrete from leaking into the pipe pile hole during the pouring of the capping beam 13; the upper anchoring part 10 is connected to the main reinforcement of the capping beam 13 through pre-embedded anchoring steel bars 11; and the design of the reserved hole 12 is crucial, as it allows the longitudinal steel bars 6 from the pile body to be directly inserted, thereby mechanically and reliably locking the pile body, the component, and the capping beam 13 together, greatly enhancing the connection strength and integrity of the joint, and achieving the goal of "integrated" construction. Example 4

[0057] A support structure constructed by the method described in Example 1, comprising: 1. Prestressed pipe pile.

[0058] The dry-hole cast-in-place pile 2 encloses the prestressed pipe pile 1, and forms a cooperative bearing structure with the prestressed pipe pile 1 through the steel mesh in the positioning support frame 5 described in Example 2.

[0059] Crown beam 13 is installed at the top of prestressed pipe pile 1.

[0060] The integrated sealing and anchoring component 8 described in Example 3 seals the pile hole of the prestressed pipe pile 1 and anchors the upper end of the longitudinal steel bar 6 and its own anchoring steel bar 11 into the cap beam 13.

[0061] It emphasizes that the structure is manufactured using a specific method, and its internal components include a "pipe pile-cast pile" collaborative load-bearing system realized by the positioning support frame 5, and a "pile-cap beam 13" rigid connection system realized by an integrated component at the top. This structural feature is the fundamental reason for its higher overall stability, stronger load-bearing capacity, and better safety performance.

[0062] Furthermore, in the support structure, the difference between the outer diameter of the positioning ring rib 4 in the positioning support frame 5 and the diameter of the dry-hole cast-in-place pile 2 ensures that the prestressed pipe pile 1 is in the central position within the dry-hole cast-in-place pile 2.

[0063] It was emphasized that the centered state of the internal pipe piles in the final composite pile product is inherently guaranteed by the dimensional matching between the support frame and the cast-in-place pile. This is one of the fundamental reasons why the structure can achieve uniform and efficient synergistic load-bearing, reflecting the precision of the design.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for constructing composite piles to enhance a support structure, wherein the support structure comprises composite piles connected by a capping beam, the composite piles being composed of internal prestressed pipe piles and externally encased dry-hole cast-in-place piles, characterized in that, The construction method includes the following steps: S1. Preparation steps of prestressed pipe pile positioning support frame: At least two positioning sections are set at intervals on the surface of the prestressed pipe pile. At each positioning section, multiple anchor bars are evenly inserted along the circumference of the pipe pile. A ring-shaped positioning ring bar is welded and fixed to the exposed ends of each anchor bar at the same section to form a positioning support frame. Multiple longitudinal steel bars are welded on the anchor bars at a certain distance from the outer wall of the pipe pile, and stirrups are set around the multiple longitudinal steel bars to form a steel mesh. S2. Pile driving and grouting steps: The prestressed pipe piles processed in step S1 are driven into the pre-formed dry-hole pile holes. The outer diameter of the positioning ring reinforcement is smaller than the diameter of the pile hole to ensure that the pipe pile is centered in the pile hole. Then, concrete is poured into the pile hole to form a dry-hole cast-in-place pile that wraps the prestressed pipe pile and the steel mesh, so that the prestressed pipe pile and the dry-hole cast-in-place pile can work together to bear the load. S3. Crown Beam Connection Steps: At the pile top, an integrated sealing and anchoring component is used to seal the pile hole of the prestressed pipe pile and anchor it to the crown beam. The integrated sealing and anchoring component has a lower sealing part that can be inserted into the pile hole and an upper anchoring part that covers the upper surface of the pile end. The upper anchoring part is pre-set with anchoring steel bars for connection with the crown beam reinforcement skeleton and has a reserved hole for the upper end of the longitudinal steel bar in step S1 to be inserted. The crown beam concrete is poured so that the upper end of the longitudinal steel bar, the anchoring steel bar of the integrated sealing and anchoring component and the space inside the reserved hole form an integral whole with the crown beam.

2. The method for constructing composite piles with enhanced support structures according to claim 1, characterized in that, In step S1, the implantation direction of the rebar corresponds to the 3 o'clock, 6 o'clock, 9 o'clock and 12 o'clock directions of the circumference of the pipe pile, respectively.

3. A method for constructing composite piles with enhanced support structures according to claim 1 or 2, characterized in that, In step S1, the diameter of the positioning ring reinforcement is greater than the outer diameter of the prestressed pipe pile and equal to the inner diameter of the dry hole pile.

4. A prestressed pipe pile positioning support frame for implementing any one of the construction methods described in claims 1 to 3, characterized in that, include: Multiple reinforcing bars are fixed to the outer wall of the prestressed pipe pile by means of rebar anchoring; The annular positioning ring is welded and fixed to the exposed ends of each of the aforementioned anchor bars at the same cross section; Longitudinal reinforcing bars are welded to the anchor bars and are spaced apart from the outer wall of the pipe pile; Stirrups are tied or welded around the perimeter of multiple longitudinal reinforcing bars, forming a reinforcing mesh together with the longitudinal reinforcing bars.

5. An integrated sealing and anchoring component for implementing any of the construction methods described in claims 1 to 3, characterized in that, It is a precast concrete component, including: The lower sealing part is a cylinder with a diameter smaller than the inner diameter of the prestressed pipe pile, which is used to be inserted into the pile hole to achieve sealing; The upper anchoring part is a plate-shaped body with a diameter larger than the outer diameter of the prestressed pipe pile, which is connected to the upper end of the lower sealing part and is used to cover the top of the pile; At least one vertical anchoring steel bar is pre-embedded in the integrated sealing and anchoring component, with its upper end extending out of the upper surface of the upper anchoring part; Multiple pre-drilled holes, penetrating the upper anchorage section, are positioned corresponding to the distribution of longitudinal reinforcing bars in the composite pile, and are used for inserting the upper ends of the longitudinal reinforcing bars.

6. A support structure constructed by the method described in any one of claims 1 to 3, characterized in that, It includes: Prestressed pipe piles; The dry-hole cast-in-place pile encloses the prestressed pipe pile and forms a cooperative load-bearing structure with the prestressed pipe pile through the steel mesh in the positioning support frame; The cap beam is installed at the top of the pile; An integrated sealing and anchoring component seals the pile hole of the prestressed pipe pile and anchors the upper end of the longitudinal reinforcement and its own anchoring reinforcement into the capping beam.

7. The support structure according to claim 6, characterized in that, The difference between the outer diameter of the positioning ring reinforcement in the positioning support frame and the diameter of the dry-hole cast-in-place pile ensures that the prestressed pipe pile is in the central position within the dry-hole cast-in-place pile.

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