A rigid-flexible precast concrete pile mold

Abstract

This invention provides a rigid-flexible precast concrete pile mold, including an upper mold and a lower mold for interlocking to form an internal columnar cavity. A longitudinal tongue-and-groove rib is provided at the mold-closing point of the upper and lower molds. Both the upper and lower molds include nested outer and inner molds. The outer mold is a rigid mold, and the inner molds are flexible molds. Two or more equally spaced inner molds are coaxially arranged within the outer mold. Both ends of the inner molds are provided with outwardly flared inclined end faces. The outer edges of the inclined end faces are attached to the inner sidewall of the outer mold. The inclined end faces of adjacent inner molds and the inner sidewall of the outer mold between them form a semi-annular groove. The inner and outer molds are connected and fixed by a semi-annular support structure. The semi-annular support structure is gap-connected to the inner molds. After the concrete hardens, during the tensioning process, when the pile body is compressed, the inner molds can undergo a slight elastic deformation following the compression deformation of the pile body. This slight deformation is absorbed by the gap between the inner and outer mold cavities, especially by the gap between the semi-annular support structure and the inner molds.

Description

Technical Field

[0001] This invention relates to the field of engineering construction technology, particularly mold equipment technology, and also to a rigid-flexible precast concrete pile mold. Background Technology

[0002] In the field of precast concrete pile construction, prestressed concrete piles constructed using the pre-tensioning method are widely used throughout China due to the high strength of the concrete and the presence of prestress. This allows them to withstand various external forces during pile driving, such as hammering and static pressure, while maintaining the integrity of the pile body. These piles are characterized by their high single-pile bearing capacity, durability, strong penetration ability, reliable quality, and relatively low cost per unit bearing capacity.

[0003] The main process for applying prestress in the centrifugal prestressed concrete pile manufacturing process is as follows: prestressed steel bars are woven into a steel cage and placed in a steel mold. Then, concrete is poured into the steel mold. The steel mold is used as a reaction device, and hydraulic jacks are used to tension the prestressed steel bars. The applied tension force is borne by the steel mold through anchor plates fixed to both ends of the steel mold. After the pile body shape is formed by centrifugal molding, steam curing is carried out to accelerate the strength development of the concrete and make the prestressed steel bars and concrete bond together. After the concrete strength reaches a certain requirement, the tension is released, and all the tension force is transferred to the pile body concrete to bear.

[0004] Taking a 15-meter pile as an example, during the release process, the pile length will experience compression of approximately 1.5-4 mm depending on the magnitude of the prestressing stress in the pile concrete. Since centrifugally formed prestressed concrete non-irregular piles (such as pipe piles and square piles) have no irregular protrusions on their outer perimeter, the inner wall of the steel mold is smooth. During release, the pile body is compressed and separates from the inner wall of the steel mold. This compression is evenly distributed throughout the pile body, preventing cracks. However, this type of smooth-walled steel mold cannot produce irregularly shaped piles. Existing centrifugally formed prestressed concrete pile production uses steel molds with a single-layer wall structure as shown in the national building materials industry standard JC / T605-2005 "Steel Molds for Prestressed Concrete Pipe Piles". When using this type of steel mold to produce prestressed concrete irregularly shaped piles, any protrusions on the pile body must be formed into concave shapes on the inner wall of the steel mold for proper shaping. During the tensioning process, when the pile body is compressed, the pile body protrusions, fixed to the concave part of the inner wall of the steel mold, cannot follow the compression deformation of the pile body. This causes cracks to appear at the joint between the pile body and the pile body protrusions, and in severe cases, the protrusions may even fall off. Moreover, the pile body cannot be separated from the steel mold, making product demolding difficult.

[0005] Significantly reducing the rigidity of the steel mold to allow for greater deformation, and adjusting the corresponding protrusions within the mold by increasing their angle and decreasing their height, can reduce the likelihood of cracks. However, such a mold, due to its low rigidity, is ill-suited to act as a reaction device to withstand the tension of prestressing. Furthermore, the mold is prone to deformation during lifting, centrifugation, and curing processes, making it unsuitable for industrial production. Additionally, the small size of the protrusions in the manufactured prestressed concrete irregular piles limits the product's application range.

[0006] Existing technologies have proposed designs to address this issue, such as a combination of a core mold and external upper and lower molds. In addition to circumferential grooves inside the upper and lower molds, longitudinal grooves are also required to prevent cracks from forming at the junction of the pile body and the pile body protrusions. However, adding longitudinal protrusions to the pile body not only increases the difficulty and cost of steel mold manufacturing, but also, under certain geological conditions, hinders the movement of pore water in the soil, thus negatively impacting bearing capacity.

[0007] Even if a solution of nesting elastic and rigid molds is adopted to address the inherent defects of irregularly shaped pile molds, new problems will still be introduced. These include complex inner mold structures, high operating costs, and high technical requirements for the connection structure between the inner and outer molds. In particular, it is difficult to simultaneously provide support for the concrete pile and allow the elastic inner mold to expand and contract with the concrete. It is evident that within the scope of existing technology, it is difficult to solve the problem of unstable, easily detached, and easily damaged protruding structures on the pile body after irregularly shaped precast concrete piles are formed through mold design optimization.

[0008] In summary, the existing molds used in precast concrete pile manufacturing have technical problems, such as the tendency for cracks to appear in the pile body, and the pile body protrusions being easily damaged. Summary of the Invention

[0009] The technical problem to be solved by this invention is that the molds used in existing precast concrete pile manufacturing processes are prone to cracking in the pile body, especially the pile body protrusions are easily damaged.

[0010] To address the aforementioned problems, this invention provides a rigid-flexible precast concrete pile mold, comprising an upper mold and a lower mold for interlocking to form an internal columnar cavity. A longitudinal tongue-and-groove reinforcing plate is provided at the joint of the upper and lower molds. Both the upper and lower molds include nested outer and inner molds. The outer mold is a rigid mold, and the inner mold is a flexible mold. Two or more inner molds are coaxially arranged within the outer mold, with adjacent inner molds spaced equidistantly along the axial direction. Both ends of each inner mold have outwardly expanding inclined end faces, the outer edges of which are fitted against the inner wall of the outer mold. The inclined end faces of adjacent inner molds and the inner wall of the outer mold between them form a semi-annular groove. The inner and outer molds are connected and fixed by a semi-annular support structure, which is gap-connected to the inner mold to allow for deformation allowance as the concrete pile expands during the forming process of the irregularly shaped concrete pile.

[0011] This type of prestressed concrete irregular pile uses a combination of inner and outer molds, employing a rigid-elastic double-walled precast pile mold. The outer mold has higher rigidity, while the inner mold has lower rigidity and is flexible and elastic. The inner surface of the steel mold formed by the inner and outer molds is adapted to the outer surface of the prestressed concrete irregular pile. The semi-annular grooves formed by the inner mold and the outer mold at the intervals are used to form the protrusions of the irregular pile. During the release of the prestressed concrete irregular pile, the gap between the semi-annular support structure and the inner mold allows the inner mold to compress and deform along with the pile body, ensuring that the protrusions of the pile body are intact and crack-free. During the irregular pile forming process, before the concrete hardens, the applied prestressing tension is mainly borne by the outer mold. The mold has low rigidity. After the concrete hardens, during the unwinding process, when the pile body is compressed, the inner mold can undergo a slight elastic deformation following the compression deformation of the pile body. This slight deformation is absorbed by the gap between the inner and outer mold cavities, especially the gap between the semi-circular support structure and the inner mold. This ensures that cracks are not easily formed at the joint between the pile body and the protrusion, allowing the pile body to separate smoothly from the mold. Because the semi-circular groove on the mold corresponding to the pile body protrusion has a sidewall formed by the inclined end face of the inner mold, this protrusion position can also adapt to the deformation of the pile body during unwinding, avoiding the situation where the protrusion structure and the pile body are not homogeneous and the connection position is prone to breakage. In addition, the elastic deformation of the inner mold during the concrete forming process recovers after the pile body separates from the mold, and the mold can be reused.

[0012] Because the inner mold adopts a split structure, that is, multiple coaxial inner molds are connected, the mold part corresponding to the irregular pile protrusion structure is a semi-annular groove formed by the inclined end face of adjacent inner molds and the inner side of the outer mold. This avoids processing a complete groove structure on the same inner mold wall, or processing multiple groove structures on the same inner mold wall multiple times. The protrusion of the irregular pile is formed by the docking position of the inner mold. This design is equivalent to optimizing the production process of the inner mold. The inner mold is composed of relatively short and relatively simple components. The formed component can be obtained by punching the two ends of each inner mold once. The multiple inner molds are connected to the outer mold through the semi-annular support structure to form the mold as a whole. The processing is relatively easy and the production cost of the mold is reduced.

[0013] As a preferred embodiment, the semi-annular support structure is a rigid semi-annular liner. The outer edge of the semi-annular liner is fixedly connected to the inner wall of the outer mold, and both ends of the inner edge of the semi-annular liner are fixedly connected to the outer wall of the inner mold. A preset distance is maintained between the middle region of the inner edge of the semi-annular liner and the outer wall of the inner mold. Optimizing the design and connection method of the semi-annular support structure strengthens the connection between the outer mold and the inner mold, and improves the support of the outer mold for the inner mold.

[0014] As a preferred embodiment, the semi-circular liner is connected to the outer mold by welding or bolting, and both ends of the semi-circular liner are welded to the inner mold. The distance between the middle region of the inner edge of the semi-circular liner and the outer wall of the inner mold ranges from 0.3mm to 1.5mm. The gap between the semi-circular liner and the inner mold is adaptively adjusted according to the deformation during the concrete pile forming process, and the fixing connection method between the semi-circular liner and the inner and outer molds is further optimized to enhance the feasibility of the mold.

[0015] As a preferred embodiment, the inclined end face of the inner mold is welded to the inner side surface of the outer mold. The weld seam is connected to the inclined end face and the inner side wall of the outer mold via an inclined transition surface. The spacing between the two weld seams within the same semi-annular groove ranges from 40mm to 120mm. Welding the inner mold and outer mold structures together provides a strong and easy-to-implement structure. Furthermore, utilizing the weld seam structure to form an inclined transition surface makes the surface of the groove structure smoother.

[0016] As a preferred embodiment, the outer wall of the outer mold is provided with two or more axial stiffeners parallel to its axis. These axial stiffeners are spaced radially apart along the outer mold and are used to enhance its rigidity. This design improves the rigidity of the outer mold, preventing deformation under stress during concrete pile forming, especially during hoisting and centrifugal processes.

[0017] As a preferred embodiment, anchor plates are fixedly connected to the end faces of both ends of the outer mold, and reinforcing ribs are evenly arranged between the anchor plates and the outer side wall of the outer mold. This structure ensures that the applied prestressing tension is mainly borne by the outer mold before the concrete hardens.

[0018] As a preferred embodiment, the outer mold comprises two or more semi-cylindrical shells connected end-to-end, with the outer side walls of each semi-cylindrical shell fixedly connected to the axial stiffener. This optimized outer mold design facilitates the molding of multiple semi-cylindrical shell connecting components, and the axial stiffeners ensure easy processing and sufficient strength after connection.

[0019] As a preferred embodiment, the outer wall of the outer mold is provided with two or more semi-annular ribs along its radial direction, and the semi-annular ribs are all spaced apart along the axial direction of the outer mold. The structure of the semi-annular ribs strengthens the outer mold in the circumferential direction and avoids circumferential deformation of the mold during the molding process.

[0020] As a preferred embodiment, the angle between the inclined end face of the inner mold and the side wall of the inner mold is greater than or equal to 110°, and the groove depth of the semi-annular groove ranges from 45mm to 150mm. The structural dimensions of this semi-annular groove ensure that the pile body is relatively easy to separate from the mold after molding, and the size and structure meet the process requirements of irregular piles.

[0021] As a preferred embodiment, the sidewall thickness of the inner mold ranges from 4mm to 8mm, the sidewall thickness of the outer mold is greater than or equal to 7mm, and the thickness of the axial stiffener does not exceed 8mm. This design ensures a relatively balanced elasticity and rigidity of the inner mold, good mold applicability, and a minimum thickness limit for the outer mold wall to ensure sufficient rigidity. The thickness of the axial stiffener adapts to process requirements. Attached Figure Description

[0022] Figure 1 A side half-section diagram of a rigid-flexible precast concrete pile mold provided by the present invention.

[0023] Figure 2 for Figure 1 A partial structural diagram of the semi-annular groove position of the medium-rigid-flexible precast concrete pile mold.

[0024] Figure 3 for Figure 1 A schematic diagram of the cross-sectional structure of a medium-rigid-flexible precast concrete pile mold.

[0025] Figure 4 for Figure 1 A schematic diagram of the inner mold of a medium-rigid-flexible precast concrete pile mold.

[0026] Figure 5A schematic diagram of the inner mold of another rigid-flexible precast concrete pile mold provided by the present invention.

[0027] in, Figures 1-5 middle:

[0028] 1. Anchor plate; 2. Inclined end face; 3. Semi-circular groove; 4. Outer mold; 5. Inner mold; 6. Semi-circular liner; 7. Longitudinal tongue and groove stiffener; 8. Axial stiffener; 9. Semi-circular stiffener; 10. Upper mold; 11. Lower mold. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] refer to Figures 1-3 , Figure 1 A side half-section diagram of a rigid-flexible precast concrete pile mold provided by the present invention. Figure 2 for Figure 1 A partial structural diagram of the semi-annular groove position of the medium-rigid-flexible precast concrete pile mold. Figure 3 for Figure 1 A schematic diagram of the cross-sectional structure of a medium-rigid-flexible precast concrete pile mold.

[0031] The rigid-flexible precast concrete pile mold provided in the embodiments of the present invention includes an upper mold 10 and a lower mold 11 for interlocking to form an internal columnar cavity. A longitudinal tongue and groove rib 7 is provided at the mold-closing point of the upper mold 10 and the lower mold 11. Both the upper mold 10 and the lower mold 11 include an outer mold 4 and an inner mold 5 nested together. The outer mold 4 is a rigid mold, and the inner mold 5 is a flexible mold. Two or more inner molds 5 are coaxially arranged inside the outer mold 4. Adjacent inner molds 5 are arranged at equal intervals along the axial direction. Both ends of the inner mold 5 are provided with outwardly expanding inclined end faces 2. The outer edge of the inclined end face 2 is attached to the inner sidewall of the outer mold 4. The inclined end faces 2 of adjacent inner molds 5 and the inner sidewall of the outer mold 4 between them form a semi-annular groove 3. The inner mold 5 and the outer mold 4 are connected and fixed by a semi-annular support structure. The semi-annular support structure is gap-connected with the inner mold 5 to reserve the deformation allowance of the inner mold 5 as the concrete pile body expands during the concrete irregular pile forming process.

[0032] This embodiment of the prestressed concrete irregular pile uses an inner and outer mold combination, employing a rigid-elastic double-walled precast pile mold. The outer mold has higher rigidity, while the inner mold has lower rigidity and is flexible and elastic. The inner surface of the steel mold formed by the inner and outer molds is adapted to the outer surface of the prestressed concrete irregular pile. The semi-annular grooves formed by the inner mold and the outer mold at the intervals are used to form the protrusions of the irregular pile. During the release of the prestressed concrete irregular pile, the gap between the semi-annular support structure and the inner mold allows the inner mold to compress and deform along with the pile body, ensuring that the protrusions of the pile body are intact and crack-free. Before the concrete hardens during the irregular pile forming process, the applied prestressing tension is mainly borne by the outer mold. Due to the low rigidity of the inner mold, during the unwinding process after the concrete hardens and the pile body is compressed, the inner mold can undergo a slight elastic deformation following the compression deformation of the pile body. This slight deformation is absorbed by the gap between the inner and outer mold cavities, especially the gap between the semi-circular support structure and the inner mold. This ensures that cracks are not easily formed at the joint between the pile body and the protrusion, allowing the pile body to separate smoothly from the mold. Since the semi-circular groove on the mold corresponding to the pile body protrusion has a sidewall formed by the inclined end face of the inner mold, this protrusion position can also adapt to the deformation of the pile body during unwinding, avoiding the situation where the protrusion structure and the pile body are not homogeneous and the connection position is prone to breakage. In addition, the elastic deformation of the inner mold during the concrete forming process recovers after the pile body separates from the mold, and the mold can be reused.

[0033] refer to Figure 4 , Figure 5 , Figure 4 for Figure 1 A schematic diagram of the inner mold of a medium-rigid-flexible precast concrete pile mold. Figure 5 A schematic diagram of the inner mold of another rigid-flexible precast concrete pile mold provided by the present invention.

[0034] To adapt to the requirements of the concrete irregular pile structure to be formed, the inner and outer mold structures are adjusted accordingly. When the pile body is required to be cylindrical, the inner mold also adopts a semi-cylindrical hollow structure. Correspondingly, when the pile body to be formed is a polygonal column, the inner mold is a semi-polygonal column structure. For example, when forming a quadrangular prism pile body, the inner molds that are connected in the upper and lower molds can be divided by a rectangular diagonal along the cross-section of the pile body.

[0035] Because the inner mold adopts a split structure, that is, multiple coaxial inner molds are connected, the mold part corresponding to the irregular pile protrusion structure is a semi-annular groove formed by the inclined end face of adjacent inner molds and the inner side of the outer mold. This avoids processing a complete groove structure on the same inner mold wall, or processing multiple groove structures on the same inner mold wall multiple times. The protrusion of the irregular pile is formed by the docking position of the inner mold. This design is equivalent to optimizing the production process of the inner mold. The inner mold is composed of relatively short and relatively simple components. The formed components can be obtained by punching the two ends of each inner mold once. The assembly line operation is standardized production. The multiple inner molds are connected to the outer mold through the semi-annular support structure to form the mold as a whole. The processing is relatively easy, which greatly improves the production efficiency of the mold and reduces the production cost of the mold.

[0036] Based on the above embodiments, in order to further optimize the semi-annular support structure and its connection with the inner and outer molds: the semi-annular support structure is a rigid semi-annular liner 6, the outer edge of the semi-annular liner 6 is fixedly connected to the inner wall of the outer mold 4, both ends of the inner edge of the semi-annular liner 6 are fixedly connected to the outer wall of the inner mold 5, and a preset distance is maintained between the middle area of ​​the inner edge of the semi-annular liner 6 and the outer wall of the inner mold 5.

[0037] In the technical solution provided in this embodiment, the semi-circular support structure specifically adopts a rigid plate structure, which has a good installation and fixing effect and strengthens the connection between the inner mold and the outer mold. It can effectively transfer the stress during pile forming to the outer mold, and achieve load bearing through the rigidity of the outer mold. It can also further improve the circumferential stiffness of the outer mold. The two ends of the semi-circular liner are fixed to the inner mold, ensuring the connection and fixation of the structure. At the same time, a certain gap is reserved in the middle area so that when the pile deforms during the concrete forming process, the inner mold can deform with the concrete surface. It can absorb the stress on the protruding parts caused by the shrinkage of the precast concrete pile during tensioning, and avoid the phenomenon of cracking due to uneven stress between the protruding parts and the pile body.

[0038] Based on the above embodiments, the fixed connection method between the semi-circular liner and the inner and outer molds is further optimized, as well as the specific reserved gap range: the semi-circular liner 6 and the outer mold 4 are connected by welding or bolts, the two ends of the semi-circular liner 6 are welded to the inner mold 5, and the distance between the middle area of ​​the inner edge of the semi-circular liner 6 and the outer side wall of the inner mold 5 is 0.3mm-1.5mm.

[0039] In this embodiment, the gap between the semi-circular liner and the inner mold is adaptively adjusted to 0.3mm-1.5mm according to the deformation during the concrete pile forming process. This can resist excessive deformation of the inner mold and prevent deviation in the dimensions of the precast pile body. Furthermore, the fixing connection method between the semi-circular liner and the inner and outer molds is optimized. Welding and threaded connections are easy to implement and have good fixing effect, which enhances the feasibility of the mold.

[0040] In the technical solution provided in this embodiment, the inclined end face 2 of the inner mold 5 is welded to the inner side surface of the outer mold 4. The weld position is connected to the inclined end face 2 and the inner side wall of the outer mold 4 through an inclined transition surface. The spacing between the two welds in the same half-annular groove 3 is 40mm-120mm. The welded connection between the inner mold and the outer mold structure is firm and easy to implement. Furthermore, by utilizing the weld structure to form an inclined transition surface, the surface of the groove structure becomes smoother. By limiting the spacing range between the welds in the same half-annular groove, the width of the protruding structure on the formed concrete pile is controlled, meeting the requirements of the construction standards.

[0041] In the technical solution provided in this embodiment, the outer wall of the outer mold 4 is provided with two or more axial stiffeners 8 parallel to its axis. The axial stiffeners 8 are all arranged at radial intervals along the outer mold 4, and the axial stiffeners 8 are used to improve the rigidity of the outer mold 4. This design improves the rigidity of the outer mold so as to resist the loads of the outer mold under complex working conditions such as centrifugation and hoisting during pile forming, and improves the concentricity of the irregular concrete precast pile.

[0042] The technical solution provided in this embodiment is mainly to optimize the connection between molds. Anchor plates 1 are fixedly connected to the end faces of both ends of the outer mold 4, and reinforcing ribs are evenly arranged between the anchor plates 1 and the outer side wall of the outer mold 4. This structure ensures that the applied prestressing tension is mainly borne by the outer mold before the concrete hardens.

[0043] Based on the above embodiments, the outer mold also adopts a split-type splicing structure: the outer mold 4 includes two or more semi-cylindrical shells connected end to end, and the outer side walls of the semi-cylindrical shells are all fixedly connected to the axial stiffeners 8. Through this structure, the outer mold design is optimized, the multiple semi-cylindrical shell connecting components are easy to form, the multiple semi-cylindrical shells are connected end to end and fixed by the axial stiffeners, which is easy to process and sufficiently strong after connection.

[0044] Similar to the principle of axial stiffeners in the above embodiments, this embodiment uses semi-circular stiffeners: two or more semi-circular stiffeners 9 are arranged radially on the outer wall of the outer mold 4, and the semi-circular stiffeners 9 are spaced apart along the axial direction of the outer mold 4. The structure of the semi-circular stiffeners strengthens the circumferential strength of the outer mold, avoids circumferential deformation of the mold during the forming process, and also improves the coaxiality of the pile body after forming.

[0045] The technical solution provided in this embodiment further optimizes the structure of the semi-annular groove. The included angle between the inclined end face 2 of the inner mold 5 and the side wall of the inner mold 5 is greater than or equal to 110°, and the groove depth of the semi-annular groove 3 is in the range of 45mm-150mm.

[0046] When the angle between the inclined end face of the inner mold and the side wall of the inner mold is less than 110°, stress concentration is easily generated at the joint between the pile body and the pile protrusion during the tensioning process. After molding, the protrusion of the pile body is easily damaged, and it is impossible to ensure smooth separation of the pile body from the mold. When the maximum depth of the semi-annular groove is less than 45mm, the centrifugally formed prestressed concrete irregular pile loses its engineering application significance. When the maximum depth of the semi-annular groove is greater than 150mm, the inclined end face of the inner mold undergoes excessive deformation due to the compression deformation of the pile body, exceeding the elastic deformation range of the mold steel. This deformation is difficult to recover, and the repeated use of the steel mold cannot be guaranteed. The structural dimensions of the semi-annular groove ensure that the pile body is relatively easy to separate from the mold after molding, and the size and structure meet the process requirements of irregular piles.

[0047] In this embodiment, the technical solution optimizes the thickness range of each part in the mold. The side wall thickness of the inner mold 5 is 4mm-8mm, the side wall thickness of the outer mold 4 is greater than or equal to 7mm, and the thickness of the axial stiffener 8 does not exceed 8mm.

[0048] The thickness of the inner mold wall should not exceed 10mm. In this embodiment, the optimal thickness of the inner mold is 5mm to 6mm. When the thickness exceeds 8mm, the inner mold becomes too rigid, making it difficult to produce even slight elastic deformation. The pile protrusions cannot separate from the inner mold sidewalls, resulting in cracks at the joint between the formed pile and the pile protrusions. Furthermore, excessive thickness leads to material waste. However, when the inner mold thickness is too thin (less than 4mm), the mold is prone to significant deformation during lifting, centrifugation, and other product manufacturing processes, causing deformation and cracks in the formed pile. During the release process, the large deformation of the inner mold easily leads to stress concentration at the joint between the pile and the pile protrusions, making it difficult to separate the pile from the mold. Similarly, the thickness range of the outer mold and axial stiffeners is mainly to ensure the rigidity of the mold structure and prevent abnormal deformation.

[0049] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A rigid-flexible precast concrete pile mold, comprising an upper mold (10) and a lower mold (11) for interlocking to form an internal columnar cavity, characterized in that, The upper mold (10) and lower mold (11) are provided with longitudinal tongue and groove ribs (7) at the mold closing point. Both the upper mold (10) and the lower mold (11) include mutually nested outer molds (4) and inner molds (5). The outer mold (4) is a rigid mold, and the inner mold (5) is a flexible mold. Two or more inner molds (5) are coaxially arranged inside the outer mold (4). Adjacent inner molds (5) are arranged at equal intervals along the axial direction. Both ends of the inner mold (5) are provided with outwardly flared inclined end faces (2). The outer edge of the inclined end face (2) is attached to the inner wall of the outer mold (4). The inclined end face (2) of the adjacent inner mold (5) and the inner wall of the outer mold (4) between them form a semi-annular groove (3). The inner mold (5) and the outer mold (4) are connected and fixed by a semi-annular support structure. The semi-annular support structure is connected to the inner mold (5) with a gap, which is used to reserve the deformation allowance of the inner mold (5) along with the concrete pile body during the concrete irregular pile forming process. The semi-annular support structure is a rigid semi-annular liner (6). Both ends of the inner edge of the semi-annular liner (6) are fixedly connected to the outer wall of the inner mold (5). The middle area of ​​the inner edge of the semi-annular liner (6) maintains a preset distance from the outer wall of the inner mold (5). The distance between the middle area of ​​the inner edge of the semi-annular liner (6) and the outer wall of the inner mold (5) is 0.3mm-1.5mm.

2. The rigid-flexible precast concrete pile mold according to claim 1, characterized in that, The semi-circular outer edge of the semi-circular liner (6) is fixedly connected to the inner wall of the outer mold (4).

3. The rigid-flexible precast concrete pile mold according to claim 2, characterized in that, The semi-annular liner (6) is connected to the outer mold (4) by welding or bolting, and the two ends of the semi-annular liner (6) are welded to the inner mold (5).

4. The rigid-flexible precast concrete pile mold according to claim 3, characterized in that, The inclined end face (2) of the inner mold (5) is welded to the inner side of the outer mold (4). The weld position is connected to the inclined end face (2) and the inner side wall of the outer mold (4) through the inclined transition. The spacing between the two welds in the same semi-annular groove (3) is 40mm-120mm.

5. The rigid-flexible precast concrete pile mold according to any one of claims 1 to 4, characterized in that, The outer wall of the outer mold (4) is provided with two or more axial stiffeners (8) parallel to its axis. The axial stiffeners (8) are all arranged at radial intervals along the outer mold (4). The axial stiffeners (8) are used to improve the rigidity of the outer mold (4).

6. The rigid-flexible precast concrete pile mold according to claim 5, characterized in that, Anchor plates (1) are fixedly connected to the end faces of both ends of the outer mold (4), and reinforcing ribs are uniformly arranged between the anchor plates (1) and the outer side wall of the outer mold (4).

7. The rigid-flexible precast concrete pile mold according to claim 5, characterized in that, The outer mold (4) includes two or more semi-cylindrical shells connected end to end, and the outer side walls of the semi-cylindrical shells are fixedly connected to the axial stiffener (8).

8. The rigid-flexible precast concrete pile mold according to claim 5, characterized in that, The outer wall of the outer mold (4) is provided with two or more semi-annular ribs (9) along its radial direction, and the semi-annular ribs (9) are all spaced apart along the axial direction of the outer mold (4).

9. The rigid-flexible precast concrete pile mold according to claim 5, characterized in that, The angle between the inclined end face (2) of the inner mold (5) and the side wall of the inner mold (5) is greater than or equal to 110°, and the groove depth of the semi-annular groove (3) is 45mm-150mm.

10. The rigid-flexible precast concrete pile mold according to claim 5, characterized in that, The sidewall thickness of the inner mold (5) is in the range of 4mm-8mm, the sidewall thickness of the outer mold (4) is greater than or equal to 7mm, and the thickness of the axial stiffener (8) does not exceed 8mm.

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