Offshore photovoltaic large-diameter high-performance concrete reducing combined pipe pile

Abstract

The invention discloses an offshore photovoltaic large-diameter high-performance concrete variable-diameter combined tubular pile, and belongs to the technical field of offshore fixed wind power equipment, the offshore photovoltaic large-diameter high-performance concrete variable-diameter combined tubular pile comprises a top pile, an extension pile and a fixed pile, the bottom of the top pile is connected with the extension pile, and the extension pile is used for enabling the fixed pile to penetrate through a soft soil layer to be embedded into a stable soil layer; and the fixed pile is mounted at the bottom of the extension pile and is used for transmitting a load to a stable soil layer. By the adoption of the offshore photovoltaic large-diameter high-performance concrete reducing combined pipe pile, the problem that a traditional pipe pile is short in adaptation in an offshore photovoltaic scene is solved, and efficient, durable and economical construction of an offshore photovoltaic foundation is achieved.

Description

Technical Field

[0001] This invention relates to the field of offshore fixed wind power equipment technology, and in particular to a large-diameter, high-performance concrete variable-diameter composite pipe pile for offshore photovoltaic systems. Background Technology

[0002] Photovoltaic energy is an important component of clean energy. With the construction of onshore photovoltaic power plants approaching saturation, offshore photovoltaics has become an important direction for photovoltaic development. my country has abundant offshore photovoltaic resources, mainly concentrated in nearshore shallow waters. Fixed offshore photovoltaic projects are the mainstream form of offshore photovoltaic development due to their mature construction technology and relatively controllable operation and maintenance costs.

[0003] Foundation piles are the core equipment for fixed offshore photovoltaic (PV) projects. They must bear the weight of the PV modules, wind and wave loads, tidal forces, and cope with the complex environment of soft offshore soil (silt, silty clay), high salt spray, and high humidity. Traditional offshore PV foundations mostly use ordinary concrete equal-diameter pipe piles or small steel pipe piles, which have insufficient adaptability: on the one hand, the bearing capacity of the deep soft soil layer in nearshore shallows is low, and the insufficient driving depth of traditional pipe piles can easily lead to excessive settlement in the later stage, affecting the verticality of the PV support; on the other hand, ordinary concrete has poor corrosion resistance and is susceptible to seawater erosion during long-term service, resulting in structural damage and requiring frequent maintenance; in addition, the overall transportation and hoisting of large-diameter long piles are difficult, resulting in low construction efficiency and high costs, making it difficult to meet the needs of large-scale offshore PV construction. Summary of the Invention

[0004] The purpose of this invention is to provide a large-diameter, high-performance concrete variable-diameter composite pipe pile for offshore photovoltaic applications, which solves the shortcomings of traditional pipe piles in adapting to offshore photovoltaic scenarios and enables efficient, durable, and economical construction of offshore photovoltaic foundations.

[0005] To achieve the above objectives, the present invention provides a large-diameter, high-performance concrete variable-diameter composite pipe pile for offshore photovoltaic applications, comprising a top pile, an extension pile, and a fixed pile. The bottom of the top pile is connected to the extension pile, which is used to allow the bottom pile to penetrate the soft soil layer and embed into the stable soil layer. The fixed pile is installed at the bottom of the extension pile and is used to transfer the load to the stable soil layer to prevent tilting.

[0006] Preferably, the top pile includes a top pipe pile and a variable diameter pipe pile, wherein the top diameter of the variable diameter pipe pile is smaller than the bottom diameter to save costs; the top pipe pile is installed on the upper part of the variable diameter pipe pile, and the diameter of the top pipe pile matches the upper diameter of the variable diameter pipe pile.

[0007] Furthermore, the top pipe pile is a PHC pipe pile with a strength of C80, a length of 4000mm, and a diameter of 1200mm, while the reducing pipe pile is a UHPC pipe pile with a strength of C120, a length of 3000mm, a top diameter of 1200mm, and a bottom diameter of 1600mm.

[0008] Preferably, the extension pile includes a first extension pipe pile, a second extension pipe pile, and a third extension pipe pile, wherein the bottom of the first extension pipe pile is connected to the second extension pipe pile, the bottom of the second extension pipe pile is connected to the third extension pipe pile, and the diameters of the first extension pipe pile, the second extension pipe pile, and the third extension pipe pile are equal.

[0009] Preferably, the top of the first extension pipe pile is connected to the variable diameter pipe pile, and the diameter of the first extension pipe pile and the bottom diameter of the variable diameter pipe pile are the same, both being 1600mm.

[0010] Furthermore, the first, second, and third extension pipe piles all have a diameter of 1600 mm and are all UHPC pipe piles with a strength grade of C120. The lengths of the first, second, and third extension pipe piles are 7000 mm, 10000 mm, and 8000 mm, respectively.

[0011] Preferably, the fixed pile includes a bottom pipe pile, which is installed at the bottom of the third extension pipe pile, and the diameter of the bottom pipe pile matches that of the third extension pipe pile.

[0012] Furthermore, the bottom pipe piles are PHC pipe piles with a strength of C80, a diameter of 1600mm, and a length of 8000mm. Salt-resistant agents and mineral admixtures are added to the high-performance concrete material of the reducing pipe piles, the first extension pipe pile, the second extension pipe pile, and the third extension pipe pile, allowing them to resist seawater erosion without the need for additional anti-corrosion coatings and improving their service life.

[0013] Preferably, the top pipe pile, the first extension pipe pile, the second extension pipe pile, the third extension pipe pile, and the bottom pipe pile are all provided with end plates and connecting steel pipes at both ends, and the reducing pipe pile is provided with platform-shaped connecting steel pipes and end plates at both ends; the top pipe pile, the reducing pipe pile, the first extension pipe pile, the second extension pipe pile, the third extension pipe pile, and the bottom pipe pile are all connected by the end plates. The weight of a single section of the above pipe pile is controlled within 300t.

[0014] Preferably, both the connecting steel pipe and the platform-shaped connecting steel pipe are radially and evenly equipped with weld plates for reinforcing the connection. The weld plates are 100-150mm long, 50-75mm wide, and 3-5mm thick, and the number of weld plates is not less than 8.

[0015] Furthermore, the end plate at the bottom of the top pipe pile is aligned and welded with the end plate at the top of the reducing pipe pile, the end plate at the bottom of the reducing pipe pile and the end plate at the top of the first extension pipe pile, the end plate at the bottom of the first extension pipe pile and the end plate at the top of the second extension pipe pile, the end plate at the bottom of the second extension pipe pile and the end plate at the top of the third extension pipe pile, and the end plate at the bottom of the third extension pipe pile and the end plate at the top of the bottom pipe pile. Then, the welding plate is placed at the weld seam of the corresponding end plate and welded to fix it. When the welding plate acts on the platform connecting steel pipe of the reducing pipe pile, the welding plate is first bent so that the two sides of the bent welding plate can be tightly attached to the platform connecting steel pipe at both ends before welding.

[0016] Preferably, the top pipe pile, the variable diameter pipe pile, the first extension pipe pile, the second extension pipe pile, the third extension pipe pile, and the bottom pipe pile are all composed of prestressed steel bars and spiral stirrups, and the prestressed steel bars are installed on the inner surface of the spiral stirrups.

[0017] Furthermore, the internal frame of the top pipe pile consists of 45 prestressed steel bars with a diameter of 14mm arranged in a ring with a diameter of 1060mm, coupled with spiral stirrups with a diameter of 8mm and a pitch of 80mm. The internal frame of the reducing pipe pile consists of 45 prestressed steel bars with a diameter of 14mm arranged in a ring with a diameter of 1060mm, but inclined to ensure a distance of 70mm from the surface, coupled with spiral stirrups with a diameter of 8mm and a pitch of 80mm. The largest diameter of the internal frame of the reducing pipe pile is 1450mm, and the smallest diameter is 1060mm. The internal frames of the first extension pipe pile, the second extension pipe pile, the third extension pipe pile, and the bottom pipe pile all consist of 76 prestressed steel bars with a diameter of 14mm arranged in a ring with a diameter of 1450mm, coupled with spiral stirrups with a diameter of 8mm and a pitch of 80mm.

[0018] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: (1) This invention addresses the problems of poor adaptability and easy settlement in soft soil strata: it designs an ultra-long 46m pile body that can penetrate five layers of soft soil, including marine silt and silty clay, and finally embed into the deep stable stratum of silty clay, effectively transferring the load to the stable soil layer; the 1.6m large diameter increases the contact area between the pile body and the soil layer, improves the resistance to lateral displacement, and solves the problem of easy tilting in soft soil. It is adapted to marine soft soil strata, ensures the verticality of the photovoltaic support, and reduces component damage caused by settlement.

[0019] (2) This invention addresses the problems of poor corrosion resistance and insufficient durability: Compared with steel-concrete composite pipe piles, this invention does not use steel pipes to encase the concrete pipe piles. Instead, it uses high-performance concrete material with added salt-resistant agents and mineral admixtures to reduce the chloride ion permeability coefficient and increase the number of freeze-thaw cycles. It can resist seawater erosion without the need for additional anti-corrosion coatings. This extends the service life of the pipe piles, reduces operation and maintenance costs, and lowers the frequency of replacement in the later stages.

[0020] (3) This invention addresses the problems of difficult construction and high cost: it adopts a segmented pile splicing node design, dividing the 46m long pile into multiple segments according to the bending moment distribution within the pile. The bending moment at both ends of the pile is relatively small, so PHC material is used for the pipe piles at both ends, and a variable diameter form is used in the top pile to save costs. The bending moment is concentrated in the middle section, so a higher strength UHPC pile is used. It is prefabricated in the factory and transported to the site for splicing. The weight of a single segment is controlled within 300t, which is compatible with existing offshore hoisting equipment. The variable diameter design (1.2m small diameter at the top and 1.6m large diameter at the bottom) reduces the amount of concrete used and lowers material costs. It shortens the construction cycle, reduces transportation and hoisting costs, and improves the efficiency of offshore construction.

[0021] (4) This invention addresses the problem of insufficient pull-out and overturning resistance: the design of an ultra-long pile increases the side friction of the pile, enhances the pull-out resistance, and can resist the vertical pull-out force of storm surges; the 1.6m large diameter increases the moment of inertia of the pile, enhances the overturning moment, and strengthens the ability to cope with lateral wave loads. It improves the resistance to extreme loads at sea, ensures the structural safety of photovoltaic power stations, and reduces the risk of damage under extreme weather conditions.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of an embodiment of a large-diameter, high-performance concrete variable-diameter composite pipe pile for marine photovoltaic applications according to the present invention. Figure 2 yes Figure 1 Enlarged structural diagram at point B; Figure 3 This is a schematic diagram of the end structure of the second extension pipe in an embodiment of a large-diameter, high-performance concrete variable-diameter composite pipe pile for marine photovoltaic applications according to the present invention. Figure 4 This is a schematic diagram of the internal structure of an embodiment of a large-diameter, high-performance concrete variable-diameter composite pipe pile for marine photovoltaic applications according to the present invention. Figure 5 yes Figure 1 Schematic diagram of the structure at point A in the middle; Figure 6 This is a schematic diagram of the internal structure of a variable-diameter composite concrete pipe pile according to an embodiment of the present invention, which is a large-diameter high-performance concrete pipe pile for marine photovoltaic applications.

[0024] Figure Labels 1. Top pipe pile; 2. Variable diameter pipe pile; 3. First extension pipe pile; 4. Second extension pipe pile; 5. Third extension pipe pile; 6. Bottom pipe pile; 7. Connecting steel pipe; 8. Welded plate; 9. End plate; 10. Prestressed steel bar; 11. Spiral stirrup; 12. Platform-shaped connecting steel pipe. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] Example 1 like Figure 1 As shown, this invention provides a large-diameter, high-performance concrete variable-diameter composite pipe pile for offshore photovoltaic applications, comprising a top pile, an extension pile, and a fixing pile. The bottom of the top pile is connected to the extension pile, which is used to allow the bottom pile to penetrate the soft soil layer and embed into the stable soil layer. The fixing pile is installed at the bottom of the extension pile and is used to transfer the load to the stable soil layer, preventing tilting.

[0028] The top pile includes a top pipe pile 1 and a reducing pipe pile 2. The top diameter of the reducing pipe pile 2 is larger than the bottom diameter to save costs. The top pipe pile 1 is installed on the upper part of the reducing pipe pile 2, and the diameter of the top pipe pile 1 matches the upper diameter of the reducing pipe pile 2.

[0029] like Figure 5 As shown, the top pipe pile 1 is a PHC pipe pile with a strength of C80, a length of 4000mm, and a diameter of 1200mm, and the reducing pipe pile 2 is a UHPC pipe pile with a strength of C120, a length of 3000mm, an upper diameter of 1200mm, and a lower diameter of 1600mm.

[0030] The extension piles include a first extension pipe pile 3, a second extension pipe pile 4, and a third extension pipe pile 5. The top of the first extension pipe pile 3 is connected to the bottom of the reducing pipe pile 2, the bottom of the first extension pipe pile 3 is connected to the second extension pipe pile 4, and the bottom of the second extension pipe pile 4 is connected to the third extension pipe pile 5. The diameters of the first extension pipe pile 3, the second extension pipe pile 4, and the third extension pipe pile 5 are all equal to the bottom diameter of the reducing pipe pile 2, which is 1600mm.

[0031] The first extension pipe pile 3, the second extension pipe pile 4, and the third extension pipe pile 5 are all UHPC pipe piles with a strength grade of C120. The lengths of the first extension pipe pile 3, the second extension pipe pile 4, and the third extension pipe pile 5 are 7000mm, 10000mm, and 8000mm, respectively.

[0032] The fixed pile includes a bottom pipe pile 6, which is installed at the bottom of the third extension pipe pile 5, and the diameter of the bottom pipe pile 6 matches that of the third extension pipe pile 5.

[0033] The bottom pipe pile 6 is a PHC pipe pile with a strength of C80, a diameter of 1600mm, and a length of 8000mm. Salt-resistant agents and mineral admixtures are added to the high-performance concrete material of the reducing pipe pile 2, the first extension pipe pile 3, the second extension pipe pile 4, and the third extension pipe pile 5, which can resist seawater erosion without the need for additional anti-corrosion coatings, thus improving service life.

[0034] like Figure 2 and Figure 3 As shown, the top pipe pile 1, the first extension pipe pile 3, the second extension pipe pile 4, the third extension pipe pile 5, and the bottom pipe pile 6 are all equipped with end plates 9 and connecting steel pipes 7 at both ends. The reducing pipe pile 2 is equipped with platform-shaped connecting steel pipes 12 and end plates 9 at both ends. The top pipe pile 1, the reducing pipe pile 2, the first extension pipe pile 3, the second extension pipe pile 4, the third extension pipe pile 5, and the bottom pipe pile 6 are all connected by welding corresponding end plates 9. The weight of a single section of the above pipe piles is controlled within 300t.

[0035] Bracket plates 8 are radially and evenly installed on the outer surface of the connecting steel pipe 7 to reinforce the connection. In this embodiment, the bracket plate 8 is 150mm long, 75mm wide, and 5mm thick, and there are 8 bracket plates 8 in total.

[0036] The end plate 9 at the bottom of the top pipe pile 1 is aligned and welded with the end plate 9 at the top of the reducing pipe pile 2, the end plate 9 at the bottom of the reducing pipe pile 2, the end plate 9 at the top of the first extension pipe pile 3, the end plate 9 at the bottom of the first extension pipe pile 3, the end plate 9 at the top of the second extension pipe pile 4, the end plate 9 at the bottom of the second extension pipe pile 4, the end plate 9 at the top of the third extension pipe pile 5, the end plate 9 at the bottom of the third extension pipe pile 5, and the end plate 9 at the top of the bottom pipe pile 6. Then, the welding plate 8 is placed at the weld seam of the corresponding end plate 9 and welded to fix it. When the welding plate 8 acts on the platform connecting steel pipe 12 of the reducing pipe pile 2, the welding plate 8 is first bent so that the two sides of the bent welding plate 8 can be tightly attached to the platform connecting steel pipe 12 at both ends before welding.

[0037] like Figure 4 and Figure 6As shown, the top pipe pile 1, the variable diameter pipe pile 2, the first extension pipe pile 3, the second extension pipe pile 4, the third extension pipe pile 5 and the bottom pipe pile 6 are all composed of prestressed steel bars 10 and spiral stirrups 11, and the prestressed steel bars 10 are installed on the inner surface of the spiral stirrups 11.

[0038] The internal frame of the top pipe pile 1 consists of 45 prestressed steel bars 10 with a diameter of 14mm arranged in a ring with a diameter of 1060mm, and spiral stirrups 11 with a diameter of 8mm and a pitch of 80mm. The internal frame of the reducing pipe pile 2 consists of 45 prestressed steel bars 10 with a diameter of 14mm arranged in a ring at an angle to ensure a distance of 70mm from the surface, and spiral stirrups 11 with a diameter of 8mm and a pitch of 80mm. The thickest diameter is 1450mm and the thinnest diameter is 1060mm. The internal frames of the first extension pipe pile 3, the second extension pipe pile 4, the third extension pipe pile 5, and the bottom pipe pile 6 all consist of 76 prestressed steel bars 10 with a diameter of 14mm arranged in a ring with a diameter of 1450mm, and spiral stirrups 11 with a diameter of 8mm and a pitch of 80mm.

[0039] The working principle is as follows: first, the sections are prefabricated, and then the end plate 9 is welded to the connecting steel pipe 7 to form a connector.

[0040] Preparation of Top Pipe Pile 1: 45 prestressed steel bars 10, each 14mm in diameter and arranged in a ring with a diameter of 1060mm, are welded to the inside of spiral stirrups 11 with a diameter of 8mm and a pitch of 80mm to form a top frame. Connectors are installed at both ends of the top frame to form a top reinforcement cage. The top reinforcement cage is placed into the pipe pile mold, and C80 grade concrete is poured in. The prestressed steel bars 10 are then tensioned, and subsequently centrifuged to produce the top pipe pile 1 with a diameter of 1200mm and a length of 4000mm.

[0041] Preparation of variable-diameter pipe pile 2: 45 prestressed steel bars 10 with a diameter of 14mm arranged in a ring are obliquely welded to the inside of spiral stirrups 11 with a diameter of 8mm and a pitch of 80mm to form a variable-diameter frame. The oblique angle ensures that the variable-diameter frame is 70mm from the surface when the preparation is completed. The thickest diameter of the variable-diameter frame is 1450mm and the thinnest diameter is 1060mm. Connectors are installed at both ends of the variable-diameter frame to form a variable-diameter reinforcing cage. The variable-diameter reinforcing cage is placed in the pipe pile mold, and after pouring in ultra-high performance concrete with a strength grade of C120, the prestressed steel bars 10 are tensioned. Subsequently, centrifugation is used to prepare a variable-diameter pipe pile 2 with a length of 3000mm, an upper diameter of 1200mm, and a lower diameter of 1600mm.

[0042] Preparation of extension piles and fixed piles: 76 prestressed steel bars 10, arranged in a ring with a diameter of 1450mm and a diameter of 14mm, are welded to the inside of spiral stirrups 11 with a diameter of 8mm and a pitch of 80mm to form a universal frame. Connectors are installed at both ends of the universal frame to form a universal reinforcing cage. The universal reinforcing cage is placed in a pipe pile mold, and after pouring in ultra-high performance concrete of strength grade C120, the prestressed steel bars 10 are tensioned. Subsequently, a first extension pipe pile 3 with a diameter of 1600mm and a length of 7000mm; a second extension pipe pile 4 with a diameter of 1600mm and a length of 10000mm; and a third extension pipe pile 5 with a diameter of 1600mm and a length of 8000mm are prepared by centrifugation. After pouring in concrete of strength grade C80, the prestressed steel bars 10 are tensioned, and then a bottom pipe pile 6 with a diameter of 1600mm and a length of 8000mm is prepared by centrifugation.

[0043] During installation, the top pipe pile 1, reducing pipe pile 2, first extension pipe pile 3, second extension pipe pile 4, third extension pipe pile 5, and bottom pipe pile 6 are transported to the project site via a flatbed transport vessel. The pipe piles are lifted sequentially. After the bottom pipe pile 6 is driven into the ground using a pile driver, the lower end plate 9 of the third extension pipe pile 5 is welded to the upper end plate 9 of the bottom pipe pile 6. The weld is reinforced with a welding plate 8. After reinforcement, the pile is driven into the ground again. After the third extension pipe pile 5 reaches the corresponding height, the lower end of the second extension pipe pile 4 is welded to the upper end plate 9 of the third extension pipe pile 5 via an end plate 9. The weld is reinforced with a welding plate 8. After reinforcement, the pile is driven into the ground again. After the second extension pipe pile 4 reaches the corresponding height, the lower end of the first extension pipe pile 3 is welded to the upper end plate 9 of the second extension pipe pile 4 via an end plate 9. The weld is reinforced with a welding plate 8. The welding of the corresponding end plate 9 is reinforced. After reinforcement, the pile is driven by the pile driver. After the first extension pipe pile 3 is driven to the corresponding height, the lower end of the variable diameter pipe pile 2 is welded to the upper end plate 9 of the first extension pipe pile 3 through the end plate 9. The welding plate 8 is bent so that the two sides of the bent welding plate 8 can be tightly attached to the platform connecting steel pipe 12 at both ends before welding reinforcement. After reinforcement, the pile is driven by the pile driver. When the variable diameter pipe pile 2 is driven to the corresponding height, the lower end of the top pipe pile 1 is welded to the upper end plate 9 of the variable diameter pipe pile 2 through the end plate 9. Similarly, the welding plate 8 is bent so that the two sides of the bent welding plate 8 can be tightly attached to the platform connecting steel pipe 12 at the end before welding reinforcement. After reinforcement, the pile is driven by the pile driver so that the whole structure penetrates five layers of soft soil, including marine silt and silty clay, and finally embeds into the deep stable stratum of silty clay. The load can be effectively transferred to the stable soil layer to complete the installation.

[0044] Therefore, the present invention adopts the above-mentioned large-diameter high-performance concrete variable-diameter composite pipe pile for offshore photovoltaic applications, which solves the shortcomings of traditional pipe piles in adapting to offshore photovoltaic scenarios and realizes efficient, durable and economical construction of offshore photovoltaic foundations.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A marine photovoltaic large-diameter high-performance concrete variable-diameter combined pipe pile, characterized in that: The utility model provides a pile structure, including top stake, extension stake and fixed stake, bottom connection has extension stake for the top stake, extension stake is used for making the fixed stake passes through soft soil layer and embeds stable soil layer;The fixed stake is installed in the bottom of extension stake, and the fixed stake is used for transmitting load to stable soil layer; The top stake includes top pipe pile and variable diameter pipe pile, the diameter of the variable diameter pipe pile top is less than the diameter of the bottom;The extension stake includes first extension pipe pile, second extension pipe pile and third extension pipe pile;The fixed stake includes bottom pipe pile; Both ends of the top pipe pile, first extension pipe pile, second extension pipe pile, third extension pipe pile and bottom pipe pile are equipped with end plate and connecting steel pipe, both ends of the variable diameter pipe pile are equipped with table type connecting steel pipe and end plate;The top pipe pile, variable diameter pipe pile, first extension pipe pile, second extension pipe pile, third extension pipe pile and bottom pipe pile are connected through the end plate; The outer surface of the connecting steel pipe and table type connecting steel pipe is equipped with the help welding plate radially and uniformly; The inside of the top pipe pile, variable diameter pipe pile, first extension pipe pile, second extension pipe pile, third extension pipe pile and bottom pipe pile is composed of prestressed steel bar and spiral hoop, and the prestressed steel bar is installed in the inner surface of the spiral hoop.

2. The offshore photovoltaic large-diameter high-performance concrete variable-diameter combined pipe pile according to claim 1, characterized in that: The top pipe pile is installed in the top of variable diameter pipe pile, and the diameter of the top pipe pile matches the diameter of the top of variable diameter pipe pile.

3. The offshore photovoltaic large-diameter high-performance concrete variable-diameter combined pipe pile according to claim 2, characterized in that: The bottom of first extension pipe pile is connected with second extension pipe pile, the bottom of second extension pipe pile is connected with third extension pipe pile, and the diameter of first extension pipe pile, second extension pipe pile and third extension pipe pile is equal.

4. The offshore photovoltaic large-diameter high-performance concrete variable-diameter combined pipe pile according to claim 3, characterized in that: The top of first extension pipe pile is connected with variable diameter pipe pile, and the diameter of first extension pipe pile is same with the diameter of the bottom of variable diameter pipe pile.

5. The offshore photovoltaic large-diameter high-performance concrete variable-diameter combined pipe pile according to claim 4, characterized in that: The bottom pipe pile is installed in the bottom of third extension pipe pile, and the diameter of bottom pipe pile matches the diameter of third extension pipe pile.

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