Stiff composite pile for enhancing prestress of pile body

Abstract

The stiff composite pile comprises a first section of prestressed tendon, the lower end of the first section of prestressed tendon is connected with a second section of prestressed tendon, the first section of prestressed tendon and the second section of prestressed tendon form a complete prestressed tendon, and the prestressed tendon is arranged at the upper end of the composite pile. A pile top anchoring device is arranged at the upper end of the composite pile around the prestressed tendon, and a pile bottom anchoring device is arranged at the lower end of the composite pile; the pile top anchoring device comprises a first fixed end anchor plate, a first extrusion head, a spring and a restraint ring, and the first section of prestressed tendon penetrates through an insertion hole in the first fixed end anchor plate. The prestressed tendons are arranged in the stiff composite pile, so that the stiff composite pile capable of enhancing the prestress of the pile body is obtained, the defect that the bearing performance of a concrete pile is low is overcome, and the technical problem that the tensile strength of inner core concrete in the stiff composite pile is insufficient is solved.

Description

Technical Field

[0001] The invention relates to the technical field of pile foundation engineering of building structure system, in particular to a rigid composite pile for enhancing the prestress of a pile body. Background Art

[0002] The rigid composite pile is an advanced pile type that combines cement-soil mixing piles and prestressed pipe piles. It forms cement-soil mixing piles by mixing, and then implants prestressed concrete pipe piles before the cement soil is initially set, so that the cement soil hardens and tightly wraps the prefabricated pile body, forming a new type of pile body with higher strength. This construction process significantly improves the compressive strength and stability of the pile body, combines the advantages of rigid piles and flexible piles, not only plays the high strength of rigid piles, but also plays the large friction area of ​​flexible piles. The length and material of the rigid pile can be flexibly adjusted, and composite piles with higher bearing capacity can be designed. Pile foundation engineering is widely used in various foundation engineering constructions in the field of civil engineering. The products used in pile foundation engineering on the current market are more concrete piles. However, with the widespread use of concrete piles, the engineering problems of low bearing capacity and poor tensile strength of concrete piles have become prominent. It has higher bearing capacity and better stability than traditional concrete piles. However, in terms of tensile performance, due to the structural characteristics of the rigid composite pile, its tensile capacity is relatively weak. This is mainly because the pile body is composed of cement soil and concrete pipe piles. These two materials have relatively low tensile strength. When the pile body is subjected to tension, cracks or even breaks easily occur. At present, the research on enhancing the prestress of the pile body is mostly focused on cast-in-place concrete piles, while the research on enhancing the prestress in rigid composite piles with higher bearing capacity and better compressive strength is relatively vacant. In addition, the existing methods for enhancing the prestress of concrete piles are mostly to set prestressed steel strands or steel cages equipped with steel strands in the concrete pile body to improve the tensile performance of the concrete pile body, but such products all have technical defects in construction technology and other aspects. Due to the insufficient bearing capacity of the concrete pile body, the structure has excessive deformation, crack expansion, and even structural damage and collapse. Engineering problems such as collapse are frequent.

[0003] Inserting a steel cage composed of steel strands and prestressed tendons into the pile body and performing prestressing at the top can effectively improve the bending resistance and fragility of the concrete pile body. However, the current related inventions still have problems in this direction, such as:

[0004] In a document of a pipe pile reinforcement cage equipped with steel strands with publication number: CN102877465B, a reinforcement cage that uses steel strands and prestressed tendons together is disclosed, which participates in the prestressing of the pipe pile concrete after the mold is closed. There are differences in the material properties of prestressed tendons and steel strands, and their tensile strengths are also different accordingly. When tensioning is performed simultaneously at the top of the concrete pile body, if low tensile strength is used for prestressing, the lower tensile strength of the prestressed tendons is effectively exerted, and the relatively high tensile strength of the steel strand prestress cannot achieve its effective performance. If high tensile strength is used for prestressing, the higher tensile strength of the steel strand prestress is effectively utilized, and the prestressed tendons are destroyed due to their excessive strength. In addition, since prestressed tendons are added to the reinforcement cage, the force performance and overall stability of the reinforcement cage may be changed when the prestressed tendons are tensioned at the top of the pile. If there is incoordination or instability between the reinforcement cage and the prestressed tendons, it will affect the overall destructive deformation of the pile body.

[0005] In addition, a method of inserting prestressed tendons into concrete piles and tensioning them at the top to reduce cracks in the piles and enhance tensile properties has been adopted, and some related product research has been conducted. However, due to various technical defects, the related inventions have problems in this direction, such as:

[0006] In the document of a pile top pre-tensioned post-tensioned pile foundation and construction process with publication number: CN108301428A, a method is disclosed in which a tendon with a bottom anchor is placed in a poured concrete pile, and the upper end of the tendon is connected to the foundation pedestal through an end anchor, and locked after prestressing. This method reveals the idea of ​​inserting prestressed tendons into concrete piles and anchoring them at the bottom and top, but the technical design has defects. The patent describes the specific operation method of the top anchor, and its bottom anchor device is only a conical enlarged head placed in a concrete pile that has not initially set. Its anchoring range is only from the top of the pile to a certain depth below the middle of the pile body. Prestress is not applied to the entire effective range of the pile body, which can easily cause discontinuous stress in the pile body and thus produce nonlinear fracture of the pile body. According to the patent content and the attached drawings, the bottom anchoring device is only a conical enlarged head, and the anchoring effect is weak. Secondly, the scheme does not disclose how to connect, anchor and produce the prestressed tendons with the bottom anchoring device. Therefore, the patent only theoretically proposes the idea of ​​setting up prestressed tendons, which cannot be used in actual production and construction. Summary of the invention

[0007] The object of the present invention is to provide a strong composite pile with enhanced prestress of the pile body, so as to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A stiff composite pile for enhancing the prestress of a pile body, comprising:

[0010] A first section of prestressed tendons, wherein the lower end of the first section of prestressed tendons is connected to a second section of prestressed tendons, the first section of prestressed tendons and the second section of prestressed tendons form a completed prestressed tendon, the prestressed tendons are arranged at the upper end of the composite pile, a pile top anchoring device is arranged around the prestressed tendons at the upper end of the composite pile, and a pile bottom anchoring device is arranged at the lower end of the composite pile;

[0011] The pile top anchoring device comprises a first fixed end anchor plate, a first extrusion head, a spring and a constraint ring, the first section of prestressed tendons passes through a plug hole in the first fixed end anchor plate, the first fixed end anchor plate is provided with a first extrusion head connected to the first section of prestressed tendons, a constraint ring is installed at the end of the first section of prestressed tendons, and a spring is provided between the constraint ring and the first fixed end anchor plate;

[0012] The pile bottom anchoring device is located at the outside of the second fixed end anchor plate, and the pile bottom anchoring device includes a screw-in sleeve with a connecting assembly, a bottom expansion tensioning arm, a soil cutting blade, a connecting arm, a connecting screw, a connecting pin, a central steel pipe sleeve, a drill bit, a movable lifting slip ring, a second fixed end anchor plate, an inner wall of the slip ring, a pulling clamp rod, a limit assembly and a second extrusion head. The second fixed end anchor plate is connected to the lower end of the second section of prestressed tendons, and the front and rear ends of the second fixed end anchor plate are respectively provided with a pulling clamp rod and a limit assembly. A second extrusion head is installed on the lower surface of the second fixed end anchor plate, and the screw-in sleeve with a connecting assembly is located at the outside of the second fixed end anchor plate, and the upper end of the screw-in sleeve with a connecting assembly is connected to the bottom of the reserved pipe in the inner core of the composite pile through a thread.

[0013] Preferably, a central steel pipe sleeve is connected to the lower end of the screw-in sleeve with the connecting assembly, a sleeve screw-in inner wall is provided at the inner wall of the screw-in sleeve with the connecting assembly, connecting pins distributed at an angle of 120° are respectively provided on the outer wall of the screw-in sleeve with the connecting assembly, a connecting arm is installed on the screw-in sleeve with the connecting assembly, the connecting arm is connected to the middle section of the bottom expansion tensioning arm, and a soil cutting blade is provided on the bottom expansion tensioning arm.

[0014] Preferably, the bottom end of the bottom expansion tensioning arm is connected to a movable lifting slip ring via a connecting screw, a slip ring inner wall is provided in the movable lifting slip ring, and connecting screws are installed at the connection between the connecting arm and the screw-in sleeve with a connecting component and the connection between the connecting arm and the bottom expansion tensioning arm, the top end of the central steel pipe sleeve is a threaded closing structure and is threadedly connected to the screw-in sleeve with a connecting component, a drill bit is provided at the lower end of the central steel pipe sleeve, and sliding grooves are opened on both sides of the central steel pipe sleeve.

[0015] Preferably, the middle and bottom portions of the bottom-expanding tensioning arm, the connecting arm and the connecting pins protruding from the outer wall of the movable lifting slip ring are all threadedly connected by connecting screws.

[0016] Preferably, the inner surface of the movable lifting slip ring is a smooth structure, the central steel pipe sleeve and the movable lifting slip ring are nested and slidably connected, and the outer wall of the central steel pipe sleeve is connected to the bottom expansion tensioning arm through a connecting pin.

[0017] Preferably, the slide groove openings are distributed on both sides of the central steel pipe sleeve, the cross-sectional shape of the slide groove openings is rectangular, the slide groove openings are adapted to the pulling card rod, and the slide groove openings and the pulling card rod are in a nested sliding connection.

[0018] Preferably, the limiting assembly fixes the pulling clamp rod to both sides of the sliding groove opening by rotating.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention provides a rigid composite pile with enhanced prestress in the pile body by arranging prestressed tendons in the rigid composite pile, which not only makes up for the defect of low bearing capacity of concrete piles, but also solves the technical problem of insufficient tensile strength of the inner core concrete in the rigid composite pile;

[0021] 2. The present invention reserves a pipeline in the inner core of the rigid composite pile, inserts prestressed tendons in the pipeline and is fixed to the second fixed end anchor plate in the bottom anchor device, tensions the prestressed tendons through the pile top, drives the clamping rods on both sides of the second fixed end anchor plate to move upward, and moves the movable lifting slip ring upward so that the connecting arm is tensioned, and the bottom expansion device is formed to be tightly clamped at the bottom of the inner and outer core pile bodies, and then the prestressed steel bars are anchored at the pile top, thereby realizing the tensioning of the prestressed tendons in the inner core of the rigid composite pile, reducing the generation of cracks and cracks in the inner core concrete, improving the tensile and compressive strength and stability of the inner core, improving the defect of insufficient tensile strength of the inner core, and improving the pull-out resistance of the rigid composite pile;

[0022] 3. The bottom anchoring device of the present invention is a connecting component, which can be connected to the reserved pipe in the core of the rigid composite pile after being assembled and fixed through corresponding threaded connection, thereby realizing the complete anchoring of the prestressed tendons at the pile top and pile bottom, improving the defect of anchoring only in a certain section of the pile length in the concrete bored pile, and compared with the traditional method of enhancing the prestress in the concrete bored pile, a new method for enhancing the prestress of the pile body in the rigid composite pile with better bearing performance and better tensile and compressive strength is provided, and the anchoring method of the prestressed tendons in the rigid composite pile of the present invention is simple and reasonable, easy to operate and low in cost, and has industrial value for application in actual engineering.

[0023] 4. When the bottom anchoring device of the present invention tensions the prestressed tendons at the top of the pile, the movable lifting and lowering sliding ring drives the bottom expansion tensioning arm to expand 120 degrees. Due to the expansion of the hole diameter of the soil at the bottom of the pile and the loose soil, the bottom hole of the core pile is expanded. By injecting concrete into the reserved pipe in the inner core, the contact area between the pile and the soil is increased, the lateral bearing capacity and vertical bearing capacity of the pile are improved, and the pile body is more stable.

[0024] 5. The bottom anchoring device in the present invention is an assembled structure. Since the bottom expansion tensioning arm for pile bottom anchoring is threadedly connected with the connecting arm and the movable lifting slip ring through connecting screws, it is only necessary to replace the bottom expansion tensioning arm of the corresponding size according to different designed pile diameters. The device structure is simple to assemble, easy to operate and highly adaptable, and can meet the use of rigid composite piles of various pile diameters. The bottom expansion tensioning arm is provided with a soil cutting blade along its entire length, which reduces the soil resistance when the top tensioning prestressed tendons are stretched to make the bottom expansion tensioning arm open upward, saving engineering costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 It is a schematic diagram of the connection structure between the fixed end anchor plate and the screw-in sleeve with a connecting assembly of the present invention;

[0027] Figure 3 It is a structural schematic diagram of the core pile top anchoring device of the present invention;

[0028] Figure 4 This is a schematic structural diagram of the core pile bottom anchoring device of the present invention;

[0029] Figure 5 It is a schematic diagram of the installation structure of the connecting arm and the screw-in sleeve with the connecting assembly of the present invention;

[0030] Figure 6 It is a schematic diagram of the fixed end anchor plate installation structure of the present invention;

[0031] Figure 7 It is a schematic diagram of the structure of the movable lifting slip ring of the present invention;

[0032] Figure 8 It is a schematic diagram of the structure of the central steel pipe sleeve of the present invention.

[0033] In the figure: 1. The first section of prestressed tendons; 2. The first extrusion head; 3. The first fixed end anchor plate; 4. The spring; 5. The restraining ring; 6. The second section of prestressed tendons; 7. The screw-in sleeve with the connecting assembly; 8. The bottom expansion tensioning arm; 9. The soil cutting blade; 10. The connecting arm; 11. The connecting screw; 12. The connecting pin; 13. The central steel pipe sleeve; 14. The drill bit; 15. The movable lifting slip ring; 16. The second fixed end anchor plate; 17. The inner wall of the slip ring; 18. The pulling rod; 19. The limit assembly; 20. The second extrusion head; 21. The sliding groove; 22. The inner wall of the sleeve. DETAILED DESCRIPTION

[0034] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0035] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] See also Figure 1-8 , an embodiment provided by the present invention:

[0039] A stiff composite pile for enhancing the prestress of a pile body, comprising:

[0040] It includes a rigid composite pile with a reserved pipe and an anchor serving the rigid composite pile to increase the prestress. The anchor serving the rigid composite pile to increase the prestress mainly includes a pile top anchor device and a pile bottom anchor device. The pile top anchor device is arranged at the top of the rigid composite pile to anchor the prestressed steel bars after tensioning. The pile bottom anchor device is preset at the bottom of the rigid core pile in advance. By tensioning the prestressed steel bars at the top, the movable lifting and lowering sliding ring is pulled upward to expand the bottom tensioning arm, thereby anchoring the prestressed steel bars at the bottom of the pile body. By arranging the prestressed steel bars in the rigid composite pile, a rigid composite pile with enhanced prestress of the pile body is obtained, which not only makes up for the defect of low bearing capacity of concrete piles, but also solves the technical problem of insufficient tensile strength of the inner core concrete in the rigid composite pile.

[0041] The reinforced composite pile with a reserved pipe is formed by mixing cement-soil mixing piles, and then the prestressed concrete pipe piles are implanted before the cement soil has initially set, so that the cement soil can tightly wrap the prefabricated pile body after hardening, forming a new type of pile body with higher strength. The reserved pipe is set in advance at the center of the inner core concrete. The reserved pipe runs from the top of the reinforced composite pile to the bottom of the pile, and the length of the reserved pipe exceeds the bottom of the pile. The excess part is threadedly connected to the screw-in sleeve with a connecting component of the pile bottom anchoring device. A pipe is reserved in the inner core of the reinforced composite pile, and prestressed tendons are inserted and fixed in the pipe. The second fixed-end anchor plate in the bottom anchor device tensions the prestressed tendons on the pile top, driving the clamping rods on both sides of the second fixed-end anchor plate to move upward, so that the movable lifting slip ring moves upward, thereby tensioning the connecting arm, forming a bottom expansion device that is tightly clamped at the bottom of the inner and outer core pile bodies and anchors the prestressed steel bars to the pile top, thereby achieving the tensioning of the prestressed tendons in the inner core of the rigid composite pile, reducing the generation of cracks and cracks in the inner core concrete, improving the tensile and compressive strength and stability of the inner core, improving the defect of insufficient tensile strength of the inner core, and improving the pull-out resistance of the rigid composite pile.

[0042] The first section of prestressed tendons, the lower end of the first section of prestressed tendons is connected to the second section of prestressed tendons, the first section of prestressed tendons and the second section of prestressed tendons form a completed prestressed tendon, the prestressed tendons are arranged at the upper end of the composite pile, the upper end of the composite pile is provided with a pile top anchoring device around the prestressed tendons, and the lower end of the composite pile is provided with a pile bottom anchoring device.

[0043] The pile top anchoring device includes a first fixed end anchor plate, a first extrusion head, a spring and a constraint ring. The first section of prestressed tendons passes through the insertion hole in the first fixed end anchor plate. The first fixed end anchor plate is provided with a first extrusion head connected to the first section of prestressed tendons. A constraint ring is installed at the end of the first section of prestressed tendons, and a spring is provided between the constraint ring and the first fixed end anchor plate.

[0044] The pile bottom anchoring device is located outside the second fixed end anchor plate. The pile bottom anchoring device includes a screw-in sleeve with a connecting assembly, a bottom expansion tensioning arm, a soil cutting blade, a connecting arm, a connecting screw, a connecting pin, a central steel pipe sleeve, a drill bit, a movable lifting slip ring, a second fixed end anchor plate, an inner wall of the slip ring, a pulling clamp rod, a limit assembly and a second extrusion head. The bottom anchoring device is an assembled structure. Since the bottom expansion tensioning arm for pile bottom anchoring is threadedly connected with the connecting arm and the movable lifting slip ring through a connecting screw, only the bottom expansion tensioning arm of the corresponding size needs to be replaced according to different designed pile diameters. The device structure is simple to assemble, easy to operate and highly adaptable, and can meet the use of rigid composite piles of various pile diameters. The soil cutting blade is provided along the entire length of the bottom expansion tensioning arm, which reduces the soil resistance when the top prestressed tendons are tensioned to make the bottom expansion tensioning arm open upward, thereby saving engineering costs.

[0045] The second fixed end anchor plate is connected to the lower end of the second section of prestressed tendons, and the front and rear ends of the second fixed end anchor plate are respectively provided with a pulling rod and a limit assembly. A second extrusion head is installed on the lower surface of the second fixed end anchor plate, and a screw-in sleeve with a connecting assembly is located outside the second fixed end anchor plate. The upper end of the screw-in sleeve with a connecting assembly is connected to the bottom of the reserved pipe in the inner core of the composite pile through a thread.

[0046] The lower end of the screw-in sleeve with a connecting component is connected to a central steel pipe sleeve, the inner wall of the screw-in sleeve with a connecting component is provided with a sleeve screw-in inner wall, and the outer wall of the screw-in sleeve with a connecting component is respectively provided with connecting pins distributed at an angle of 120°. When the bottom anchoring device tensions the prestressed tendons at the top of the pile, the bottom expansion tensioning arm is driven by the movable lifting slip ring to expand 120°. Due to the enlarged diameter of the soil at the bottom of the pile and the loose soil, the bottom hole of the core pile is expanded. Concrete is injected into the reserved pipe in the inner core, thereby increasing the contact area between the pile and the soil, improving the lateral bearing capacity and vertical bearing capacity of the pile, and making the pile body more stable.

[0047] A connecting arm is installed on the screw-in sleeve with a connecting assembly, and the connecting arm is connected to the middle section of the bottom expansion tensioning arm. A soil cutting blade is arranged on the bottom expansion tensioning arm. The connecting pins protruding from the middle and bottom of the bottom expansion tensioning arm, the connecting arm and the outer wall of the movable lifting slip ring are all threadedly connected by connecting screws.

[0048] The bottom end of the bottom expansion tensioning arm is connected with a movable lifting slip ring through a connecting screw. The inner surface of the movable lifting slip ring has a smooth structure. The central steel pipe sleeve and the movable lifting slip ring are nested and slidably connected. The outer wall of the central steel pipe sleeve is connected to the bottom expansion tensioning arm through a connecting pin.

[0049] The movable lifting slip ring is provided with an inner wall of the slip ring, and connecting screws are installed at the connection between the connecting arm and the screw-in sleeve with the connecting component and the connection between the connecting arm and the bottom expansion tensioning arm. The top of the central steel pipe sleeve is a threaded closing structure and is threadedly connected with the screw-in sleeve with the connecting component. A drill bit is provided at the lower end of the central steel pipe sleeve. Slide grooves are opened on both sides of the central steel pipe sleeve. The slide grooves are distributed on both sides of the central steel pipe sleeve. The cross-sectional shape of the slide grooves is rectangular. The slide grooves are adapted to the pulling rod. The slide grooves and the pulling rod are nested and slidably connected. The limit assembly fixes the pulling rod to both sides of the slide groove by rotation.

[0050] The working principle of the present invention is as follows: before making the concrete core pile in advance, the center position of the pile body is located by a caliper and a pipe is inserted, and the length of the bottom of the pipe is reserved to exceed the bottom of the core pile;

[0051] Cast-in-place concrete forms a rigid composite pile core concrete pile body with a reserved pipeline;

[0052] Prestressed tendons are inserted into the reserved pipeline, and the bottom of the prestressed tendons passes through the second fixed end anchor plate of the bottom anchor device in advance and is anchored through the second extrusion head. The pulling clamping rod is welded to both sides of the second fixed end anchor plate in advance, and the pulling clamping rods on both sides of the second fixed end anchor plate with prestressed tendons are placed into the interior of the central steel pipe sleeve along the sliding grooves on both sides of the central steel pipe sleeve, and the limiting components are clamped on both sides of the grooves of the central steel pipe sleeve. After the above-mentioned movable lifting slip ring is inserted into the outer wall of the central steel pipe sleeve, the threaded interface on the top of the central steel pipe sleeve is screwed into the sleeve with the connecting component. Threaded connection is performed, the threaded slot hole at the bottom of the expanded bottom tensioning arm with an angle of 120° is aligned with the threaded slot hole of the connecting pin on the outer wall of the movable lifting slip ring with an angle of 120°, and a connecting screw is used for threaded connection, the threaded slot in the middle of the expanded bottom tensioning arm is aligned with the threaded slot at one end of the connecting arm, and a connecting screw is used for threaded connection, the threaded slot at the other end of the connecting arm is aligned with the threaded slot of the connecting pin with an angle of 120° in the screw-in sleeve with the connecting component, and a connecting screw is used for threaded connection, and the bottom anchoring device is assembled;

[0053] Thread the upper part of the screw-in sleeve with the connection assembly in the assembled bottom anchoring device to the reserved pipe inside the core pile;

[0054] Before the construction of cast-in-place cement soil, an appropriate position is excavated downward from the pile bottom elevation to place the anchoring device. After the cast-in-place cement soil, the precast concrete inner core pile, in which the prestressed tendons have been inserted into the reserved pipe and assembled with the bottom anchoring device, is inserted into the cement soil to form a rigid composite pile with an anchoring device at the bottom, and the cement soil inside the inner core reserved pipe is extracted using an external device;

[0055] After the prestressed tendons in the inner core pipe pass through the constraint ring at the top of the pile and are closed, an external power device is used to tension the prestressed tendons, driving the bottom anchoring device to operate, and the bottom expansion tensioning arm is unfolded and the hole is expanded to fit tightly to the bottom of the pile body. After the prestressed tendons are tensioned, they pass through the first fixed end anchor plate and are anchored at the top using the first extrusion head. A spring is passed under the first fixed end anchor plate in advance. Finally, concrete is evenly injected into the reserved pipe to the top of the pile to complete the specific construction.

[0056] The above is only an embodiment of the present invention, and the common sense such as the known specific structure and characteristics in the scheme is not described in detail here. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the attached claims rather than the above description, so it is intended to include all changes within the meaning and scope of the equivalent elements of the claims. Any figure mark in the claims should not be regarded as limiting the claims involved.

Claims

1. A rigid composite pile for enhancing the prestress of the pile body, characterized in that: It includes: A first section of prestressed tendons (1), the lower end of the first section of prestressed tendons (1) is connected to a second section of prestressed tendons (6), the first section of prestressed tendons (1) and the second section of prestressed tendons (6) form a completed prestressed tendon, the prestressed tendons are arranged at the upper end of the composite pile, a pile top anchoring device is arranged around the prestressed tendons at the upper end of the composite pile, and a pile bottom anchoring device is arranged at the lower end of the composite pile; The pile top anchoring device comprises a first fixed end anchor plate (3), a first extrusion head (2), a spring (4) and a restraining ring (5); the first section of prestressed tendon (1) passes through a plug hole in the first fixed end anchor plate (3); the first fixed end anchor plate (3) is provided with a first extrusion head (2) connected to the first section of prestressed tendon (1); a restraining ring (5) is installed at the end of the first section of prestressed tendon (1); a spring (4) is provided between the restraining ring (5) and the first fixed end anchor plate (3); The pile bottom anchoring device is located outside the second fixed end anchor plate (16), and comprises a screw-in sleeve (7) with a connecting assembly, a bottom expansion tensioning arm (8), a soil cutting blade (9), a connecting arm (10), a connecting screw (11), a connecting pin (12), a central steel pipe sleeve (13), a drill bit (14), a movable lifting slip ring (15), a second fixed end anchor plate (16), an inner wall of the slip ring (17), a pulling clamp rod (18), a limit assembly (19) and a second extrusion head (20), wherein the second The fixed end anchor plate (16) is connected to the lower end of the second section of prestressed tendons (6); the front and rear ends of the second fixed end anchor plate (16) are respectively provided with a pulling rod (18) and a limit assembly (19); a second extrusion head (20) is installed on the lower surface of the second fixed end anchor plate (16); the screw-in sleeve (7) with the connecting assembly is located outside the second fixed end anchor plate (16); the upper end of the screw-in sleeve (7) with the connecting assembly is connected to the bottom of the reserved pipe in the inner core of the composite pile through a thread.

2. A rigid composite pile for enhancing the prestress of the pile body according to claim 1, characterized in that: The lower end of the screw-in sleeve (7) with the connecting assembly is connected to a central steel pipe sleeve (13), the inner wall of the screw-in sleeve (7) with the connecting assembly is provided with a sleeve screw-in inner wall (22), the outer wall of the screw-in sleeve (7) with the connecting assembly is respectively provided with connecting pins (12) distributed at an angle of 120°, a connecting arm (10) is installed on the screw-in sleeve (7) with the connecting assembly, the connecting arm (10) is connected to the middle section of the bottom expansion tensioning arm (8), and the bottom expansion tensioning arm (8) is provided with a soil cutting blade (9).

3. A rigid composite pile for enhancing the prestress of the pile body according to claim 1, characterized in that: The bottom end of the bottom expansion tensioning arm (8) is connected to a movable lifting slip ring (15) via a connecting screw (11), a slip ring inner wall (17) is arranged inside the movable lifting slip ring (15), and connecting screws (11) are installed at the connection points between the connecting arm (10) and the screw-in sleeve (7) with a connecting component and between the connecting arm (10) and the bottom expansion tensioning arm (8), the top end of the central steel pipe sleeve (13) is a threaded closing structure and is threadedly connected to the screw-in sleeve (7) with a connecting component, a drill bit (14) is arranged at the lower end of the central steel pipe sleeve (13), and sliding grooves (21) are opened on both sides of the central steel pipe sleeve (13).

4. A rigid composite pile for enhancing the prestress of the pile body according to claim 2, characterized in that: The middle and bottom parts of the bottom-expanding tensioning arm (8), the connecting arm (10) and the connecting pins protruding from the outer wall of the movable lifting slip ring (15) are all threadedly connected via connecting screws (11).

5. The rigid composite pile for enhancing the prestress of the pile body according to claim 3, characterized in that: The inner surface of the movable lifting slip ring (15) has a smooth structure, the central steel pipe sleeve (13) and the movable lifting slip ring (15) are nested and slidably connected, and the outer wall of the central steel pipe sleeve (13) is connected to the bottom expansion tensioning arm (8) through a connecting pin.

6. A rigid composite pile for enhancing the prestress of the pile body according to claim 3, characterized in that: The slide groove openings (21) are distributed on both sides of the central steel pipe sleeve (13); the cross-sectional shape of the slide groove openings (21) is rectangular; the slide groove openings (21) are adapted to the pull-on clamping rod (18); and the slide groove openings (21) and the pull-on clamping rod (18) are in nested sliding connection.

7. The rigid composite pile for enhancing the prestress of the pile body according to claim 1, characterized in that: The limiting assembly (19) fixes the pulling clamp rod (18) to the two sides of the sliding groove opening (21) by rotating.

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