Deep water area based combined pile and staged forming method thereof

Abstract

The application provides a combined pile based on a deep water area and a staged forming method thereof. The combined pile comprises a steel pipe pile, a bottom of an assembled pipe column, a top of the steel pipe pile, a steel reinforcement cage coaxially arranged in the assembled pipe column, a connecting assembly, a filling core concrete, and a combined pile. The connecting assembly is partially arranged in the steel pipe pile and partially arranged in the assembled pipe column. The filling core concrete is filled in the steel pipe pile and the assembled pipe column, and the filling core concrete wraps the connecting assembly and the steel reinforcement cage in the assembled pipe column to form a whole force combined pile. The long steel pipe pile which is easy to be corroded in water is replaced by the prefabricated reinforced concrete assembled pipe column, and the service life is prolonged. Meanwhile, the range of the expensive anticorrosive steel material is reduced to only the mud section, the anticorrosive cost is decoupled from the water depth, and the total cost of the deep water project is reduced. The whole force design ensures the structural strength and feasibility.

Description

Technical Field

[0001] This invention relates to the field of marine foundation engineering technology, specifically to a composite foundation pile based on deep water areas and its phased construction method. Background Technology

[0002] In composite pile foundations used in marine engineering, extremely high requirements are placed on the corrosion resistance and life-cycle cost of the piles in order to ensure the long-term stability and economic feasibility of the structure in harsh marine environments. Currently, the mainstream types of foundation piles mainly include two categories. The first category is all-steel composite foundation piles, such as steel pipe piles and steel columns connected by grouting, with the entire structure being steel. The second category is an improved scheme based on this, which involves filling the shallow water section of the steel pipe pile with concrete to form a steel-concrete composite structure, and using comprehensive anti-corrosion measures such as sacrificial anodes and heavy-duty protective coatings to extend service life. This type of scheme has been applied in construction scenarios with shallow water depths, such as the Donghai Bridge (water depth of approximately 10 meters); however, the above scheme has the following drawbacks: (1) All-steel structure foundation piles have a short service life (usually about 20 years) because the steel is submerged in seawater for a long time and the corrosion rate is fast. (2) Although the improved scheme can improve the life of the foundation piles in shallow water, its anti-corrosion cost is highly dependent on the protection range. When applied to deep water areas (such as 40 meters, 60 meters or deeper), the area and volume of the steel structure that needs to be protected increase significantly, resulting in a sharp increase in the comprehensive anti-corrosion expenses such as coating maintenance and anode block replacement, which become extremely expensive. Summary of the Invention

[0003] This application provides a composite foundation pile for deep water areas and its phased construction method, which solves the technical problems of the short service life caused by the easy corrosion of the all-steel composite foundation piles used in the prior art, and the fact that the corrosion prevention cost of the existing corrosion-resistant schemes increases sharply with the increase of water depth.

[0004] In a first aspect, embodiments of this application provide a composite foundation pile based on a deep water zone, which includes: a steel pipe pile, which is inserted into the mud surface of the deep water zone; The prefabricated pipe column is connected at its bottom to the top of the steel pipe pile; a steel reinforcement cage is coaxially installed inside the prefabricated pipe column. The connecting component has one part located inside the steel pipe pile and the other part located inside the prefabricated pipe column; The core-filling concrete is used to fill the interior of the steel pipe pile and the prefabricated pipe column, and the part of the connecting component located inside the prefabricated pipe column is wrapped and connected to the steel reinforcement cage inside the prefabricated pipe column, forming a composite foundation pile in which the steel pipe pile, the prefabricated pipe column, the connecting component and the core-filling concrete are integrally stressed.

[0005] In conjunction with the first aspect, in one embodiment, the prefabricated tubular column includes multiple tubular column units; Multiple pipe column units are fixedly connected vertically to form a prefabricated pipe column; the lowest pipe column unit is connected to the top of the steel pipe pile.

[0006] In conjunction with the first aspect, in one embodiment, the column unit includes a precast concrete column, one end of which is provided with a connecting protrusion and the other end is provided with a connecting groove adapted to the connecting protrusion, so that adjacent column units can be connected by the cooperation of the connecting protrusion and the connecting groove.

[0007] In conjunction with the first aspect, in one embodiment, the inner wall surface of the precast concrete column is configured as a wavy joint surface.

[0008] In conjunction with the first aspect, in one embodiment, an anti-sinking plate is provided on the outer side of the bottom of the lowest column unit, and a sealing device is provided on its inner wall for sealing the gap between the column unit and the outer wall of the steel pipe pile.

[0009] In conjunction with the first aspect, in one embodiment, the reinforcing cage includes a plurality of reinforcing cage units, each reinforcing cage unit including a main reinforcing cage and a first connecting reinforcing cage. Each precast concrete column has a steel cage unit coaxially arranged inside; wherein, the main steel cage is coaxially arranged inside the precast concrete column, one end of the first connecting steel cage is connected to the main steel cage, and the other end passes through the precast concrete column and is located on the periphery of the connecting groove.

[0010] In conjunction with the first aspect, in one embodiment, the end of the first connecting steel cage furthest from the main steel cage is inclined toward the central axis of the first connecting steel cage.

[0011] In conjunction with the first aspect, in one embodiment, the inner wall of the steel pipe pile is provided with a support plate; The connecting assembly includes a grout stop plate, a limiting tube, and a second connecting steel cage disposed within the limiting tube; The grout stop plate is supported on the support plate, and the upper part of the second connecting steel cage extends out of the limiting tube and is located inside the prefabricated pipe column.

[0012] In conjunction with the first aspect, in one embodiment, a water passage hole is provided on the grout stop plate; the connecting assembly also includes a grout stop ball with a diameter larger than that of the water passage hole, the grout stop ball being detachably placed on the water passage hole for sealing the water passage hole.

[0013] Secondly, embodiments of this application provide a phased construction method for composite foundation piles in deep water areas, comprising: Prefabricated tubular columns consist of multiple tubular column units; Prefabricate steel pipe piles, connecting components, and multiple pipe column units for sequential connection to form prefabricated pipe columns in the land area; and drive steel pipe piles at the target pile locations in the deep water area. After connecting a guide steel pipe to the connecting assembly, it is lowered so that the connecting assembly is supported inside the steel pipe pile and the top of the guide steel pipe is positioned above the waterline. Multiple pipe column units are suspended and connected along the outside of the guide steel pipe to form a prefabricated pipe column; Provide horizontal constraints for the prefabricated tubular column, and then pull the guide steel pipe out from inside the prefabricated tubular column; Lower the grout conduit into the prefabricated column until the lower end of the grout conduit is at the first preset distance from the connecting component; lower the grout stop ball connected to the suspension rope into the grout conduit, and continuously inject core-filling concrete into the grout conduit at the same time; When the grout stop ball is at a first preset distance from the connecting component, the hoisting rope is cut, and the underwater core filling concrete is poured.

[0014] The beneficial effects of the technical solutions provided in this application include: This paper proposes a composite pile foundation for deep-water applications. The original long steel pipe piles, which require significant corrosion protection in the water, are replaced with precast reinforced concrete assembled pipe columns. Since the precast reinforced concrete structure is resistant to seawater corrosion, its service life is extended. The steel pipe piles can be protected using impressed current cathodic protection and a reserved corrosion thickness. Due to concerns about the low corrosion rate in the mud section and the insufficient durability of the circuitry in the impressed current cathodic protection system, a reserved corrosion margin is generally adopted, resulting in relatively low cost. This corrosion protection measure is only required for the relatively shorter steel pipe piles in the mud section, thus the cost does not increase significantly with water depth. Furthermore, the core concrete filling the steel pipe piles reduces seawater corrosion of its inner walls.

[0015] To ensure the structural strength, this application employs a connecting component installed inside the steel pipe pile, with its upper part extending into the prefabricated pipe column. The prefabricated pipe column contains a coaxial reinforcing cage. After the core-filling concrete is poured, a continuous reinforcing cage is formed, ensuring that bending moment and shear force can be effectively transferred from the upper prefabricated pipe column to the lower steel pipe pile and foundation. This extends the service life and reduces construction costs while maintaining structural strength. It also solves the technical problems of existing all-steel composite foundation piles being susceptible to corrosion, resulting in a short service life, and the fact that the corrosion protection costs of existing corrosion-resistant solutions increase dramatically with water depth. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of the composite pile foundation in deep water zone provided in an embodiment of this application; Figure 2 A cross-sectional structural diagram of a composite pile foundation in deep water zone provided for an embodiment of this application; Figure 3 A schematic diagram of a steel pipe pile structure for a composite foundation pile in deep water provided in this application embodiment; Figure 4 A schematic diagram of a pipe column unit structure for a composite pile foundation in deep water zones provided in this application embodiment; Figure 5 A schematic cross-sectional view of a composite pile unit in deep water zone provided for an embodiment of this application; Figure 6 A schematic cross-sectional view of the lowest pipe column unit of the composite pile foundation in deep water zone provided for the embodiments of this application; Figure 7 A schematic diagram of the connection component structure of the composite foundation pile based on the deep water zone provided in the embodiments of this application; Figure 8 This is a structural schematic diagram of the first stage of the composite foundation pile after the guide steel pipe is lowered in the molding construction method. Figure 9 This is a structural schematic diagram of the second stage of the combined foundation pile after multiple pipe column units are lowered in the molding construction method. Figure 10 This is a structural schematic diagram of the third stage of the composite foundation pile after the guide steel pipe is extracted and horizontal constraints are provided to the prefabricated pipe column in the molding process. Figure 11 This is a schematic diagram of the fourth stage of the composite pile foundation where the grout conduit is inserted and the core-filling concrete is introduced into it during the molding process. Figure 12 A structural schematic diagram of the fifth stage of the composite foundation pile where the grout ball is used to stop sealing the water passage hole and the core filling concrete is continuously poured during the molding process. Figure 13 A schematic diagram of the overall structure after the completion of the composite pile foundation construction.

[0018] In the diagram: 1. Steel pipe pile; 101. Support plate; 2. Prefabricated pipe column; 21. Pipe column unit; 211. Precast concrete column; 2111. Connecting protrusion; 2112. Connecting groove; 2113. Grout stop pad; 2114. Corrugated joint surface; 212. Packer; 213. Anti-settlement plate; 3. Connecting assembly; 31. Grout stop plate; 310. Water passage hole; 32. Limiting pipe; 33. Second connecting reinforcement cage; 34. Grout stop ball; 35. Guide plate; 4. Core filling concrete; 5. Reinforcement cage unit; 51. Main reinforcement cage; 52. First connecting reinforcement cage; 6. Water level line; 7. Guide steel pipe; 8. Grout conduit; 9. Mud level line; 10. Horizontal restraint. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0020] To make the technical problem that this application aims to solve clearer, the causes of the technical problem will be analyzed in detail below: The short service life of existing all-steel composite pile foundations is due to their susceptibility to corrosion. This problem stems from a fundamental mismatch between the material properties and the service environment. Current technology employs an all-steel structure, exposing the steel to the highly corrosive marine environment for extended periods. In typical marine environments, the corrosion rate of steel reaches 0.2–0.5 mm / a in the most severely corrosive splash zone and 0.12–0.2 mm / a in areas with fluctuating water levels. Continuous electrochemical corrosion leads to a gradual thinning of the steel pipe pile wall, weakening its structural strength and stability. Because both the underwater and scour sections of the pile are steel structures, the lack of a corrosion barrier typically limits its overall design life to around 20 years. Therefore, the short lifespan is caused by the inability of the main steel structure material to withstand the corrosion of its long-term service environment. The problem of the drastically increased cost of existing corrosion-resistant solutions in deep water lies in the lack of economic scalability of traditional additional protection methods under deep-water conditions. While improved technologies, exemplified by the Donghai Bridge project, extend service life to 100 years through a combination of cathodic protection and heavy-duty protective coatings, rely on providing a uniformly distributed and continuously supplied free electron curtain to the steel structure and precisely applying a close-fitting protective layer to the exposed surfaces. The cost of this approach directly and non-linearly depends on the surface area of ​​the steel structure requiring protection. When applied to areas with water depths of 40 meters, 60 meters, or deeper, the underwater length of the foundation piles increases exponentially, leading to a geometric increase in the surface area of ​​the steel structure requiring protection. This not only dramatically increases protection costs but also exponentially increases the difficulty, risk, and time required for maintenance and repair of defects in protective measures under harsh deep-sea conditions, resulting in prohibitively high overall corrosion protection expenses.

[0021] It is important to understand that foundation piles in deep-sea environments include an underwater section, an scour section, and a submerged section. The underwater section refers to the portion of the foundation pile above the undisturbed ground surface; the scour section refers to the portion between the undisturbed ground surface and the local scour line; and the submerged section refers to the portion below the local scour line. The composite foundation pile provided in this application employs a reinforced concrete structure in the underwater section, a steel pipe filled with reinforced concrete in the scour section, and a steel pipe pile structure in the submerged section.

[0022] Firstly, reference Figures 1 to 13 ,in Figure 1 This is a schematic diagram of the overall structure of a composite pile foundation in deep water, provided in an embodiment of this application. The embodiment of this application provides a composite pile foundation in deep water, comprising: Steel pipe pile 1, which is inserted into the mud surface of the deep water area; The prefabricated pipe column 2 is connected at its bottom to the top of the steel pipe pile 1; a steel reinforcement cage is coaxially installed inside the prefabricated pipe column 2. The connecting component 3 has one part located inside the steel pipe pile 1 and the other part located inside the prefabricated pipe column 2; The core-filling concrete 4 fills the interior of the steel pipe pile 1 and the prefabricated pipe column 2, and the part of the connecting component 3 located inside the prefabricated pipe column 2 is wrapped and connected with the steel reinforcement cage inside the prefabricated pipe column 2, forming a composite foundation pile in which the steel pipe pile 1, the prefabricated pipe column 2, the connecting component 3 and the core-filling concrete 4 are subjected to overall force.

[0023] By setting up this type of composite foundation pile, the long steel pipe pile 1, which originally required special corrosion protection in the water area, is replaced with precast reinforced concrete assembled pipe column 2. Since the precast reinforced concrete structure itself is resistant to seawater corrosion, the service life can be extended. The steel pipe pile 1 can adopt the impressed current cathodic protection method and the protective measures of reserving corrosion thickness. Due to the low corrosion rate of the mud section and concerns about the insufficient durability of the circuit in the impressed current cathodic protection system, the anti-corrosion measures of reserving corrosion margin are generally adopted, which is relatively low in cost. Moreover, this anti-corrosion measure only needs to be adopted for the relatively shorter steel pipe pile 1 in the mud section, so the anti-corrosion cost will not increase significantly with the increase of water depth. In addition, the core concrete 4 filled in the steel pipe pile 1 can also reduce the corrosion of its inner wall by seawater.

[0024] To ensure the structural strength, this application employs a connecting component 3 installed inside the steel pipe pile 1, with its upper part extending into the prefabricated pipe column 2. The prefabricated pipe column 2 contains a reinforcing cage coaxially. After the filling concrete 4 is poured, a continuous reinforcing cage is formed, ensuring that bending moment and shear force can be effectively transferred from the upper prefabricated pipe column 2 to the lower steel pipe pile 1 and foundation. This extends the service life and reduces construction costs while ensuring structural strength. It also solves the technical problems of existing all-steel composite foundation piles being easily corroded, resulting in a short service life, and the corrosion resistance cost of existing corrosion-resistant solutions increasing sharply with water depth.

[0025] It is important to know that during actual construction, the top of the prefabricated pipe column 2 is generally located near the waterline 6, that is, a certain distance above or below the water level. This is because this is the foundation to be connected. Its bottom usually needs to be slightly below the waterline to avoid direct collision of the pile body with ships. When there is no risk of collision or the collision will not cause the pile body to become unstable and damaged, it can also be above the waterline.

[0026] To make the content of this application clearer, the phased construction method for composite pile foundations in deep water areas will be analyzed below; this application provides a phased construction method for composite pile foundations in deep water areas, which includes: The prefabricated tubular column 2 includes multiple tubular column units 21; In the land area, prefabricate steel pipe piles 1, connecting components 3, and multiple pipe column units 21 for sequentially connecting to form prefabricated pipe columns 2; and drive steel pipe piles 1 at the target pile location in the deep water area. After connecting the guide steel pipe 7 to the connecting assembly 3, it is lowered so that the connecting assembly 3 is supported inside the steel pipe pile 1. Along the outside of the guide steel pipe 7, multiple pipe column units 21 are suspended and connected to form prefabricated pipe columns 2; Provide horizontal constraints for the prefabricated column 2, and then pull the guide steel pipe 7 out from inside the prefabricated column 2; Lower the grout conduit 8 into the prefabricated column 2 until the lower end of the grout conduit 8 is at a first preset distance from the connecting component 3; lower the grout stop ball 34 connected with the suspension rope into the grout conduit 8, and at the same time continuously inject the core filling concrete 4 into the grout conduit 8. When the grout stop ball 34 is at the first preset distance from the connecting component 3, the hoisting rope is cut and the underwater core filling concrete 4 is poured.

[0027] On-site construction in harsh deep-sea environments, whether welding long sections of steel pipe piles or pouring large volumes of concrete underwater, is a highly challenging, high-risk, and high-quality-fluctuation operation. This method breaks down the project into the following controllable stages: The prefabricated core components (pipe column unit 21 and connecting assembly 3) are completed in a well-equipped land-based factory, making quality control easier. Guide steel pipes 7 are used as guides to precisely and quickly align and connect the prefabricated pipe column units 21. These guide steel pipes 7 also serve as temporary load-bearing structures to assist in bearing the wave and current loads acting on the installed pipe column units 21, ensuring structural stability during construction. This simplifies the complex structural forming problem into a mechanical hoisting and connection problem, improving construction efficiency, accuracy, and safety. Finally, the core-filling concrete 4 is poured within the formed, permanent closed cavity (i.e., inside the steel pipe pile 1 and the prefabricated pipe column 2). This avoids the risks of ocean current disturbance, environmental pollution, and quality control issues associated with directly pouring concrete in open seawater. The horizontal restraint component 10 provides horizontal restraint for the prefabricated pipe column 2.

[0028] The guiding function of the guide steel pipe 7 is manifested in the fact that the prefabricated pipe column 2 is connected by multiple pipe column units 21, and the guide steel pipe 7 in this method ensures the verticality and coaxiality of each pipe column unit 21 during the lowering process, so that the connection between the pipe column units 21 can be accurately completed, which is the guarantee for the realization of the prefabricated structure. On the other hand, the grout stop ball 34 prevents the grout from being diluted by seawater and causing concrete segregation, ensuring that the initial concrete is continuously and smoothly delivered to the bottom of the hole. Therefore, the first preset distance is specifically set according to the actual construction scenario, and generally does not exceed one meter.

[0029] It should be noted that the lower end of the inserted steel pipe pile 1 is below the local scour line, and the upper end is above the mudline 9 and below the waterline 6.

[0030] Furthermore, in one embodiment, the prefabricated column 2 includes a plurality of column units 21; Multiple pipe column units 21 are fixedly connected vertically to form prefabricated pipe columns 2; among them, the pipe column unit 21 located at the bottom is connected to the top of the steel pipe pile 1.

[0031] In this embodiment, the large, integral prefabricated column 2 structure is decomposed into multiple standardized column units 21 with more controllable size and weight. Each column unit 21 can be prefabricated under the superior conditions of a land-based factory, thereby enabling precise control of the concrete mix ratio, steel reinforcement protective layer thickness, vibration compaction, and curing conditions. This ensures that each column unit 21 possesses excellent corrosion resistance and structural strength, which is unmatched by offshore cast-in-place construction. Moreover, compared to hoisting a single long column, the segmented units are lighter and smaller, significantly reducing the requirements for offshore lifting equipment capabilities and making transportation and on-site operations safer and more flexible. By increasing or decreasing the number of column units 21 or using column units 21 of different lengths, the overall height of the prefabricated column 2 can be flexibly adjusted, thus economically and conveniently adapting to engineering needs at different water depths.

[0032] Furthermore, in one embodiment, the column unit 21 includes a precast concrete column 211. One end of the precast concrete column 211 is provided with a connecting protrusion 2111, and the other end is provided with a connecting groove 2112 adapted to the connecting protrusion 2111, so that adjacent column units 21 can be connected through the cooperation of the connecting protrusion 2111 and the connecting groove 2112.

[0033] This embodiment provides a specific and operable method for the sequential vertical connection of multiple tubular units 21. In deep-water, low-visibility, and complex hydrological environments, precise adjustments or complex connection operations (such as welding and bolt tightening) by construction personnel or equipment are extremely difficult and costly. By designing a guide-socket interface with connecting protrusions 2111 and connecting grooves 2112, the complex underwater alignment problem is transformed into a mechanical guidance and positioning problem. When the upper tubular unit 21 is lowered, its connecting protrusions 2111 fall into the already positioned connecting grooves 2112 of the lower tubular unit 21, thereby achieving self-alignment, reducing reliance on underwater precision positioning equipment, and simplifying operations. The cooperation between the connecting protrusions 2111 and the connecting grooves 2112 can constrain the radial displacement and relative rotation between adjacent tubular units 21, ensuring the straightness of the vertical axis of the entire prefabricated tubular unit 2.

[0034] Furthermore, in one embodiment, the inner wall surface of the precast concrete column 211 is configured as a wavy joint surface.

[0035] In this embodiment, the prefabricated pipe column 2 is installed first, followed by the pouring of the core-filling concrete 4 to bond them together. If the bonding surface is a smooth plane, it is prone to debonding under the influence of differences in shrinkage and creep of concrete at different ages and the long-term cyclic action of strong external loads, thereby weakening the overall stiffness and bearing capacity of the composite pile. By setting a wavy bonding surface, the surface area of ​​the bonding surface is increased and mechanical interlocking force is provided to resist shear slippage of the bonding surface of concrete at different ages, ensuring that the two are bonded into a solid whole.

[0036] Furthermore, in one embodiment, the bottom outer side of the lowest column unit 21 is provided with an anti-sinking plate 213, and its inner wall is provided with a sealing device 212 for sealing the gap between the column unit 21 and the outer wall of the steel pipe pile 1.

[0037] In this embodiment, the purpose of the anti-sinking plate 213 is to prevent vertical deformation of the entire prefabricated pipe column 2 during the pouring and curing of the filling concrete 4; the purpose of the packer 212 is to seal the annular gap between the inner wall of the precast concrete column 211 and the outer wall of the steel pipe pile 1, preventing a large amount of concrete slurry from leaking out of the gap when the filling concrete 4 is poured. In other embodiments, the packer 212 can be omitted by connecting a transverse rib with a connecting groove to the outside of the limiting tube 32 to support the connecting protrusion of the lowest pipe column unit.

[0038] Furthermore, in one embodiment, the reinforcing cage includes a plurality of reinforcing cage units 5, and the reinforcing cage unit 5 includes a main reinforcing cage 51 and a first connecting reinforcing cage 52. Each precast concrete column 211 has a steel cage unit 5 coaxially arranged inside; wherein, the main steel cage 51 is coaxially arranged in the body of the precast concrete column 211, one end of the first connecting steel cage 52 is connected to the main steel cage 51, and the other end passes through the precast concrete column 211 and is located around the connecting groove 2112.

[0039] In this embodiment, the core of this application lies in phased molding, that is, first forming the precast concrete outer shell (assembled pipe column 2), and then pouring the core-filling concrete 4. This embodiment also adapts the reinforcement system to this process. The overall reinforcing cage is divided into reinforcing cage units 5, each corresponding to a precast concrete column 211. This allows the reinforcing cage and the concrete column to be precast simultaneously and integrally formed in a land-based factory, ensuring the accuracy of the reinforcing bar position and the thickness of the protective layer, thus guaranteeing the quality of the component. Each reinforcing cage unit is clearly divided into two parts: the main reinforcing cage 51 and the first connecting reinforcing cage 52. The first connecting reinforcing cage 52 penetrates the concrete column and is located around the connecting groove 2112, creating connection conditions for subsequent construction stages. The portion of the reinforcing bar extending out of the concrete body acts as a reserved connecting bar.

[0040] Furthermore, in one embodiment, the end of the first connecting steel cage 52 that is away from the main steel cage 51 is inclined toward the central axis of the first connecting steel cage 52.

[0041] In this embodiment, in deep water, currents and waves cause the suspended tubular unit 21 to sway, making it difficult to precisely align with the already positioned unit or the central guide structure. The inwardly inclined end of the first connecting steel cage 52 physically forms a funnel-shaped opening, wider at the bottom than the top. As the tubular unit 21 is lowered along the guide pipe 7, this funnel more easily captures and guides the guide pipe 7 into its center. Even if the tubular unit 21 sways slightly, the inclined steel end will generate a radial force to right it upon contact with the guide pipe 7, thus achieving self-alignment and simplifying underwater fine-tuning operations.

[0042] Furthermore, in one embodiment, the inner wall of the steel pipe pile 1 is provided with a support plate 101; The connecting assembly 3 includes a grout stop plate 31, a limiting tube 32, and a second connecting steel cage 33 disposed within the limiting tube 32; The grout stop plate 31 is supported on the support plate 101, and the upper part of the second connecting steel cage 33 extends out of the limiting tube 32 and is located inside the prefabricated pipe column 2.

[0043] In this embodiment, a support plate 101 is pre-installed on the inner wall of the steel pipe pile 1, providing a horizontal, robust, and precisely positioned support surface for the subsequently installed grout stop plate 31. This ensures that the entire connecting assembly 3 can be quickly and accurately installed to the design elevation. The core function of the grout stop plate 31 is sealing. It is supported on the support plate 101 and cooperates with the inner wall of the steel pipe pile 1. When pouring the core filling concrete 4, it prevents the concrete slurry from leaking from the bottom of the steel pipe pile 1, ensuring that the concrete can only fill upwards within the design cavity. The limiting tube 32 is connected to the grout stop plate 31, and its tube wall is provided with grout passage holes. It plays a guiding and limiting role, and is used to guide and accommodate the guide steel pipe 7 during the construction phase.

[0044] It should be noted that a guide plate 35 is also provided on the outer wall of the limiting tube 32.

[0045] Furthermore, in one embodiment, a water passage hole 310 is provided on the grout stop plate 31; the connecting component 3 also includes a grout stop ball 34 with a diameter larger than that of the water passage hole 310, and the grout stop ball 34 can be detachably placed on the water passage hole 310 to block the water passage hole 310.

[0046] In this embodiment, before the concrete pouring begins, when the grout conduit 8 is lowered close to the grout stop plate 31, the concrete grout inside the grout conduit 8 will displace the seawater near the bottom of the grout conduit 8. The water passage hole 310 is designed to reduce the water resistance during the insertion of the connecting assembly 3 into the steel pipe pile 1; otherwise, the water inside the steel pipe pile 1 can only drain through the gap between the edge of the grout stop plate 31 and the inner wall of the steel pipe pile 1. This gap is small, resulting in significant water resistance. The grout stop ball 34 serves to maintain the integrity of the initial concrete grout during its descent, preventing it from being diluted by seawater and segregating, which would affect the quality of the concrete at the bottom of the hole. It also seals the water passage hole 310, preventing uncured concrete grout from leaking out through this hole.

[0047] The beneficial effects of this application include: (1) A composite pile foundation based on deep water area is proposed, in which the long steel pipe pile 1, which is originally located in the water area and requires key corrosion protection, is replaced with precast reinforced concrete assembled pipe column 2. Since the precast reinforced concrete structure itself can resist seawater corrosion, it can achieve the effect of extending service life; the steel pipe pile 1 can adopt the cathodic protection method of impressed current and the protective measures of reserving corrosion thickness. Due to the low corrosion rate of the mud section and the concern about the insufficient circuit durability of the impressed current cathodic protection system, the anti-corrosion measures of reserving corrosion margin are generally adopted, which is relatively low cost. Moreover, this anti-corrosion measure only needs to be adopted for the relatively shorter steel pipe pile 1 in the mud section, so the anti-corrosion cost will not increase significantly with the increase of water depth; and the filling of the steel pipe pile The core-filling concrete 4 inside the steel pipe pile 1 can also reduce the corrosion of its inner wall by seawater; in order to ensure the supporting strength of the structure, this application adopts a connecting component 3 installed inside the steel pipe pile 1, with its upper part extending into the prefabricated pipe column 2, and a steel reinforcement cage coaxially installed inside the prefabricated pipe column 2. After the core-filling concrete 4 is poured, a continuous steel reinforcement skeleton is formed, which ensures that the bending moment and shear force can be effectively transferred from the upper prefabricated pipe column 2 to the lower steel pipe pile 1 and the foundation, thereby extending the service life and reducing the construction cost while ensuring the supporting strength; it solves the technical problems of the existing technology that the all-steel structure composite foundation pile is easily corroded, resulting in a short service life, and the corrosion prevention cost of the existing corrosion-resistant scheme will increase sharply with the increase of water depth.

[0048] (2) A phased construction method for composite piles in deep water is proposed. In the harsh deep water environment, on-site construction, whether it is welding long steel pipe piles 1 or underwater large-volume concrete pouring, is a high-difficulty, high-risk, and high-quality fluctuating operation. This method decomposes the project into the following controllable stages: the prefabricated core components (pipe column unit 21, connecting components 3) are completed in a land-based factory with superior conditions, making quality control easier; using guide steel pipes 7 as guides, the prefabricated pipe column units 21 are precisely and quickly aligned and connected, and the guide steel pipes 7 serve as temporary load-bearing structures to assist in bearing the wave and current loads acting on the installed pipe column units 21, ensuring structural stability during construction. This simplifies the complex structural forming problem into a mechanical hoisting and connection problem, improving construction efficiency, accuracy, and safety; finally, the core-filling concrete 4 is poured in the closed cavity formed as a permanent template (i.e., inside the steel pipe pile 1 and the prefabricated pipe column 2), which avoids the risks of ocean current disturbance, environmental pollution, and quality control failure faced by directly pouring concrete in open seawater. The guiding function of the guide steel pipe 7 is manifested in the fact that the prefabricated pipe column 2 is connected by multiple pipe column units 21, and the guide steel pipe 7 in this method ensures the verticality and coaxiality of each pipe column unit 21 during the lowering process, so that the connection between the pipe column units 21 can be accurately completed, which is a guarantee for the realization of the prefabrication. On the other hand, the combined operation of the grout conduit 8 and the grout stop ball 34 can ensure that when the core filling concrete 4 is injected, the initial grout can maintain its integrity as it continuously and smoothly reaches the bottom of the pouring hole, ensuring that the concrete quality of the steel-concrete connection section at the bottom of the pouring hole meets the requirements.

[0049] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0050] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0051] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A composite foundation pile for deep water areas, characterized in that, It includes: Steel pipe piles (1) are inserted into the mud surface of deep water areas; The prefabricated pipe column (2) has its bottom connected to the top of the steel pipe pile (1); a steel cage is coaxially arranged inside the prefabricated pipe column (2); The connecting component (3) has one part located inside the steel pipe pile (1) and the other part located inside the prefabricated pipe column (2); The core-filling concrete (4) fills the interior of the steel pipe pile (1) and the prefabricated pipe column (2), and the part of the connecting component (3) located inside the prefabricated pipe column (2) is wrapped and connected with the steel cage inside the prefabricated pipe column (2) to form a composite foundation pile in which the steel pipe pile (1), the prefabricated pipe column (2), the connecting component (3) and the core-filling concrete (4) are subjected to overall force. The prefabricated pipe column (2) includes multiple pipe column units (21); the multiple pipe column units (21) are fixedly connected in sequence along the vertical direction to form the prefabricated pipe column (2); wherein, the pipe column unit (21) located at the bottom is connected to the top of the steel pipe pile (1); The column unit (21) includes a precast concrete column (211), one end of which is provided with a connecting protrusion (2111) and the other end is provided with a connecting groove (2112) adapted to the connecting protrusion (2111), so that adjacent column units (21) can be connected by the cooperation of the connecting protrusion (2111) and the connecting groove (2112). The steel cage includes multiple steel cage units (5), and each steel cage unit (5) includes a main steel cage (51) and a first connecting steel cage (52). Each of the precast concrete columns (211) has a steel cage unit (5) coaxially arranged inside; wherein, the main steel cage (51) is coaxially arranged in the body of the precast concrete column (211), one end of the first connecting steel cage (52) is connected to the main steel cage (51), and the other end passes through the precast concrete column (211) and is located around the connecting groove (2112); The inner wall of the steel pipe pile (1) is provided with a support plate (101); the connecting assembly (3) includes a grout stop plate (31), a limiting tube (32) and a second connecting steel cage (33) disposed in the limiting tube (32); the grout stop plate (31) is supported on the support plate (101), and the upper part of the second connecting steel cage (33) extends out of the limiting tube (32) and is located in the prefabricated pipe column (2); The grout stop plate (31) has a water passage hole (310); the connecting assembly (3) also includes a grout stop ball (34) with a diameter larger than that of the water passage hole (310). The grout stop ball (34) can be detachably placed on the water passage hole (310) to block the water passage hole (310).

2. The composite foundation pile based on deep water areas as described in claim 1, characterized in that: The inner wall surface of the precast concrete column (211) is set as a wavy joint surface (2114).

3. The composite foundation pile based on deep water areas as described in claim 1, characterized in that: The bottom outer side of the lowest column unit (21) is provided with an anti-sinking plate (213), and its inner wall is provided with a packer (212) for sealing the gap between the column unit (21) and the outer wall of the steel pipe pile (1).

4. The composite foundation pile based on deep water areas as described in claim 1, characterized in that: The end of the first connecting steel cage (52) away from the main steel cage (51) is inclined toward the central axis of the first connecting steel cage (52).

5. A phased construction method for composite foundation piles in deep water areas, characterized in that, It includes: Provide the composite foundation piles based on deep water zones as described in claim 1; The prefabricated column (2) includes multiple column units (21); The steel pipe piles (1), the connecting components (3), and a plurality of the pipe column units (21) for sequentially connecting to form the prefabricated pipe column (2) are prefabricated in the land area; and the steel pipe piles (1) are driven into the target pile location in the deep water area. After connecting a guide steel pipe (7) to the connecting assembly (3), it is lowered so that the connecting assembly (3) is supported inside the steel pipe pile (1) and the top of the guide steel pipe is located above the water surface line (6). Along the outside of the guide steel pipe (7), multiple of the column units (21) are suspended and connected to form the prefabricated column (2). Provide horizontal constraints for the prefabricated column (2), and then pull the guide steel pipe (7) out of the prefabricated column (2); Lower the grout conduit (8) into the prefabricated column (2) until the lower end of the grout conduit (8) is a first preset distance from the connecting component (3); lower the grout stop ball (34) connected with the suspension rope into the grout conduit (8), and continuously inject the core filling concrete (4) into the grout conduit (8). When the grout stop ball (34) is at a first preset distance from the connecting component (3), the hoisting rope is cut and the underwater core filling concrete (4) is poured.

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