Deepwater bridge pile foundation structure and design method

Abstract

The invention relates to a deepwater bridge pile foundation structure and a design method, and relates to the technical field of bridge deepwater pile foundation design. The pile foundation body is arranged on the lower side of the bearing platform; the steel casing is arranged on the outer side of the pile foundation body in a sleeving manner and extends into the bearing platform; and the set number of outer side stress main reinforcements are connected with the outer side of the steel casing and are arranged at intervals in the circumferential direction of the steel casing, and the upper ends of the outer side stress main reinforcements are connected with the bearing platform. Due to the fact that the steel casing extends into the bearing platform, the upper ends of the outer side stress main reinforcements with the set number are connected with the bearing platform, the steel casing participates in permanent stress of the structure, and the outer side stress main reinforcements with the set number are matched with the steel casing and the pile foundation body to participate in stress together. The specific number of the outer side stress main reinforcements is obtained by considering the corrosion allowance of the steel casing after corrosion, the problem that steel participates in stress corrosion is effectively avoided, the mode of additionally arranging the outer side stress main reinforcements is simpler, and the outer side stress main reinforcements are more convenient to manufacture.

Description

Technical Field

[0001] The present invention relates to the technical field of deep-water bridge pile foundation design, and in particular to a deep-water bridge pile foundation structure and a design method. Background Art

[0002] The construction of cross-sea bridges is characterized by deep water, strong scouring, large waves and strong winds. In order to meet the needs of structural stress, the foundation design scale is much larger than that of conventional land bridge foundations, which leads to the common characteristics that the foundation investment accounts for a large proportion, reaching more than 70%. In order to make the bridge structure safe and reliable, the following measures are often taken: (1) increasing the number of pile foundations or increasing the diameter of the pile foundation so that a larger foundation scale can be used to withstand the bridge load in the marine environment; (2) increasing the foundation burial depth so that the external load mainly acts on the relatively small bridge piers rather than on the relatively large pedestals and pile foundations; (3) using steel casing to participate in the permanent structure stress, and participating in the stress of the pile group foundation by considering a certain wall thickness (considering the corrosion allowance after 100 years of corrosion in the marine environment) to increase the bearing capacity requirement of the pile group foundation.

[0003] In the prior art, for example, patent number CN119041402A discloses a cast-in-place pile foundation module for preventing seawater erosion and its construction method. The module comprises an outer casing, an inner casing is sleeved inside the outer casing, a casting part is arranged inside the cylinder body of the inner casing, a gap is provided between the inner casing and the outer casing, a water-filled water bag is provided in the gap, and the water-filled water bag can fill the gap after being filled with water. Compared with the traditional permanent steel casing, the present invention can fully isolate the concrete pile from seawater by the outer casing, the water-filled water bag and the inner casing before the steel cage is placed under the concrete pile, and the inner casing can be pulled out before the pile foundation begins to set, and a module is formed by using the outer casing and the water bag. Moreover, since the module is detachable, the outer casing and the water-filled water bag can be removed after the pile foundation is formed, which reduces the cost and also avoids the inner casing being left in the seawater to cause corrosion and pollution to the environment.

[0004] However, the design of the cast-in-place pile foundation module to prevent seawater erosion is relatively complicated. During actual construction, water-filled bags need to be arranged on site and used to support the concrete pile foundation that has not yet initially set. The stability of the water-filled bags needs to be determined through experiments, which increases the construction steps and prolongs the construction period. Summary of the Invention

[0005] The present application provides a deep-water bridge pile foundation structure and design method, which can solve the problem that the design of the cast-in-place pile foundation module for preventing seawater erosion in the existing technology is relatively complex. During actual construction, water-filled water bags need to be arranged on site, and the water-filled water bags are used to support the concrete pile foundation that has not yet initially set. The stability of the water-filled water bags needs to be determined through experiments, which increases the construction steps and prolongs the construction period.

[0006] In a first aspect, an embodiment of the present application provides a deep-water bridge pile foundation structure, comprising:

[0007] The cap, the upper side of which is used to connect with the pier;

[0008] A pile foundation body, which is arranged on the lower side of the cap;

[0009] A steel casing is sleeved on the outside of the pile foundation body and extends into the cap;

[0010] A set number of outer main stress reinforcements are connected to the outer side of the steel casing and are arranged at intervals along the circumference of the steel casing. The upper ends of the outer main stress reinforcements are connected to the base.

[0011] In one embodiment, the pile foundation body is provided with inner main reinforcement, and the inner main reinforcement is arranged along the outer circumference of the pile foundation body.

[0012] In one embodiment, two groups of the inner side stress-bearing main reinforcements are provided in the pile foundation body, and the two groups of the inner side stress-bearing main reinforcements are arranged along a ring, and the two groups of the inner side stress-bearing main reinforcements are arranged concentrically.

[0013] In one embodiment, the distance between the outermost side of the inner stress-bearing main reinforcement and the outer wall of the pile foundation body meets the protective layer thickness required by the pile foundation body.

[0014] In one embodiment, the outer main reinforcement is connected to the steel casing by double-sided welding.

[0015] In one embodiment, the outer main reinforcement includes an inclined section and a straight section, the straight section is connected to the steel casing, and the inclined section is connected to the upper end of the straight section and extends into the base.

[0016] In one embodiment, the upper end of the inclined section faces a direction away from the axis of the steel casing.

[0017] In a second aspect, an embodiment of the present application further provides a method for designing a deep-water bridge pile foundation structure, which is used to design the above-mentioned deep-water bridge pile foundation structure, comprising the following steps:

[0018] Obtain the design structural parameters of the steel casing and the outer main reinforcement, as well as the actual structural parameters of the steel casing under corrosion conditions;

[0019] The set number of outer main reinforcement bars is determined based on the design structural parameters of the steel casing and the outer main reinforcement bars, as well as the actual structural parameters of the steel casing under corrosion conditions.

[0020] In one embodiment, the method of determining the set number of outer main reinforcement bars based on the design structural parameters of the steel casing and the outer main reinforcement bars, as well as the actual structural parameters of the steel casing under corrosion conditions, includes:

[0021] The set number of outer main reinforcement bars is obtained based on the outer diameter of the steel casing, the designed wall thickness of the steel casing, the wall thickness of the steel casing after corrosion, the design value of the tensile strength of the outer main reinforcement bars, the area of ​​a single outer main reinforcement bar, and the design value of the tensile strength of the steel.

[0022] In one embodiment, according to the formula: Obtain the set number of outer main reinforcement bars;

[0023] Among them, n is the set number of external main reinforcement, D is the outer diameter of the steel casing, d is the wall thickness of the steel casing, and d ， is the wall thickness after corrosion, f d is the design value of tensile strength of steel, f sd is the design value of tensile strength of the outer main reinforcement, s Δ is the area of ​​a single outer main reinforcement bar.

[0024] The beneficial effects of the technical solutions provided in the embodiments of the present application include:

[0025] When designing the pile foundation structure for this deepwater bridge, the upper side of the cap is used to connect to the bridge pier, the pile foundation body is located on the lower side of the cap, and a steel casing is installed outside the pile foundation body and extends into the cap. A set number of outer main reinforcement bars are connected to the outer side of the steel casing and spaced around the circumference of the steel casing, with the upper end of the outer main reinforcement bar connected to the cap. The set number of outer main reinforcement bars is determined by obtaining the design structural parameters of the steel casing and the outer main reinforcement bars, as well as the actual structural parameters of the steel casing under corrosive conditions. The set number of outer main reinforcement bars is determined based on the design structural parameters of the steel casing and the outer main reinforcement bars, as well as the actual structural parameters of the steel casing under corrosive conditions. Since the steel casing extends into the pedestal, a set number of outer stress-bearing main reinforcement upper ends are connected to the pedestal, and the steel casing participates in the permanent stress of the structure, and a set number of outer stress-bearing main reinforcement cooperates with the steel casing and the pile foundation body to participate in the stress. The specific number of outer stress-bearing main reinforcement is derived from the corrosion allowance of the steel casing after considering corrosion, which effectively avoids the problem of steel participating in stress corrosion. The method of adding outer stress-bearing main reinforcement is simpler and more convenient to manufacture, and solves the problem that the design of the cast-in-place pile foundation module for preventing seawater erosion in the existing technology is relatively complex. In actual construction, water-filled water bags need to be arranged on site, and water-filled water bags are used to support the uninitialized concrete pile foundation. The stability of the water-filled water bags needs to be determined through experiments, which increases the construction steps and prolongs the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1 It is a structural schematic diagram of an embodiment of a deep-water bridge pile foundation structure of the present invention.

[0028] Figure 2 This is a partially enlarged structural schematic diagram of an embodiment of a deep-water bridge pile foundation structure of the present invention.

[0029] Figure 3 This is a schematic cross-sectional structural diagram of a combined structure of a pile foundation body and a steel casing in an embodiment of a deep-water bridge pile foundation structure of the present invention.

[0030] In the figure: 1. Cap; 2. Pier; 3. Pile foundation body; 31. Inner load-bearing main reinforcement; 4. Steel casing; 5. Outer load-bearing main reinforcement. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] The embodiments of the present application provide a deep-water bridge pile foundation structure and design method, which can solve the problem that the design of the cast-in-place pile foundation module for preventing seawater erosion in the prior art is relatively complex. During actual construction, water-filled water bags need to be arranged on site, and the water-filled water bags are used to support the uninitialized concrete pile foundation. The stability of the water-filled water bags needs to be determined through experiments, which increases the construction steps and prolongs the construction period.

[0033] like Figure 1 、 Figure 2 and Figure 3 As shown, on the one hand, the present application provides a deep-water bridge pile foundation structure, which includes:

[0034] A cap 1, the upper side of which is used to connect with the pier 2;

[0035] The pile foundation body 3 is arranged on the lower side of the cap 1;

[0036] The steel casing 4 is sleeved on the outside of the pile foundation body 3 and extends into the cap 1;

[0037] A set number of outer main reinforcement bars 5 are connected to the outer side of the steel casing 4 and are arranged at intervals along the circumference of the steel casing 4. The upper ends of the outer main reinforcement bars 5 are connected to the base 1.

[0038] When designing the deepwater bridge pile foundation structure, the upper side of the cap 1 is used to connect with the pier 2, the pile foundation body 3 is set on the lower side of the cap 1, and the steel casing 4 is sleeved on the outside of the pile foundation body 3 and extends into the cap 1. A set number of outer main reinforcement bars 5 are connected to the outer side of the steel casing 4 and are arranged at intervals along the circumference of the steel casing 4. The upper ends of the outer main reinforcement bars 5 are connected to the cap 1. The set number of outer main reinforcement bars 5 is determined by obtaining the design structural parameters of the steel casing 4 and the outer main reinforcement bars 5, as well as the actual structural parameters of the steel casing 4 under corrosive conditions, and then determining the set number of outer main reinforcement bars 5 based on the design structural parameters of the steel casing 4 and the outer main reinforcement bars 5, as well as the actual structural parameters of the steel casing 4 under corrosive conditions. Since the steel casing 4 extends into the pedestal 1, the upper ends of a set number of outer stress-bearing main reinforcements 5 are connected to the pedestal 1, and the steel casing 4 participates in the permanent stress of the structure, and the set number of outer stress-bearing main reinforcements 5 cooperate with the steel casing 4 and the pile foundation body 3 to participate in the stress. The specific number of outer stress-bearing main reinforcements 5 is derived from the corrosion allowance of the steel casing 4 after considering corrosion, which effectively avoids the problem of steel participating in stress corrosion. The method of adding outer stress-bearing main reinforcements 5 is simpler and more convenient to manufacture, which solves the problem that the design of the cast-in-place pile foundation module for preventing seawater erosion in the existing technology is relatively complex. During actual construction, water-filled water bags need to be arranged on site, and water-filled water bags are used to support the uninitialized concrete pile foundation. The stability of the water-filled water bags needs to be determined through experiments, which increases the construction steps and prolongs the construction period.

[0039] In addition, the calibration of the set number of outer main reinforcement bars 5 takes into account multiple design structural parameters. The calibration results are obtained through precise quantitative calculations, with high precision and good reliability, ensuring the safety of the designed deep-water bridge pile foundation structure while reasonably controlling costs.

[0040] In this example, stirrups are provided around the outer ring of the outer main reinforcement 5 to ensure the stability of the outer main reinforcement 5 .

[0041] like Figure 3 As shown, in some optional embodiments, an inner main stress-bearing reinforcement 31 is provided in the pile foundation body 3 , and the inner main stress-bearing reinforcement 31 is arranged along the outer circumference of the pile foundation body 3 .

[0042] In this embodiment, an inner load-bearing main reinforcement 31 is provided in the pile foundation body 3. The inner load-bearing main reinforcement 31 is arranged along the outer circumference of the pile foundation body 3. The inner load-bearing main reinforcement 31 and the outer load-bearing main reinforcement 5 cooperate with each other to bear the force together, which can greatly improve the bearing capacity requirement and correspondingly reduce the foundation scale, thereby achieving the result of significantly reducing construction costs.

[0043] like Figure 3 As shown, in some optional embodiments, two groups of inner stress-bearing main reinforcements 31 are provided in the pile foundation body 3 , and the two groups of inner stress-bearing main reinforcements 31 are arranged along a ring, and the two groups of inner stress-bearing main reinforcements 31 are arranged concentrically.

[0044] In this embodiment, two groups of inner stress-bearing main reinforcements 31 are provided in the pile foundation body 3. Both groups of inner stress-bearing main reinforcements 31 are arranged along a ring, and the two groups of inner stress-bearing main reinforcements 31 are arranged concentrically, which makes the spatial arrangement more reasonable and more stable when subjected to stress.

[0045] In some optional embodiments, the distance between the outermost side of the inner stress-bearing main reinforcement 31 and the outer wall of the pile foundation body 3 satisfies the protective layer thickness required by the pile foundation body 3 .

[0046] In this embodiment, the distance between the outermost side of the inner load-bearing main reinforcement 31 and the outer wall of the pile foundation body 3 meets the protective layer thickness required by the pile foundation body 3, thereby ensuring the structural stability of the pile foundation body 3 and preventing the protective layer thickness from reducing, thereby preventing the effect of protecting the pile foundation body 3 from being reduced and affecting the durability of the pile foundation body 3.

[0047] In this example, if there are two sets of inner main reinforcement bars 31, the distance between the outermost side of the inner main reinforcement bars 31 and the outer wall of the pile foundation body 3 satisfies the required protective layer thickness of the pile foundation body 3. The protective layer thickness is 7 cm.

[0048] In some optional embodiments, the outer main reinforcement 5 is connected to the steel casing 4 by double-sided welding.

[0049] In this embodiment, the outer load-bearing main reinforcement 5 is connected to the steel casing 4 by double-sided welding. Double-sided welding significantly increases the cross-sectional area of ​​the weld by superimposing the deposited metal on both sides, thereby improving the tensile, bending and shear strength of the joint, and can effectively avoid defects such as incomplete penetration and porosity that may exist in single-sided welding, ensuring the air tightness or liquid tightness of the joint. It can also offset part of the welding thermal deformation through symmetrical heating and cooling, reduce the risk of workpiece distortion, and evenly distribute residual stress to improve structural stability.

[0050] like Figure 1 and Figure 2 As shown, in some optional embodiments, the outer main reinforcement 5 includes an inclined section and a straight section, the straight section is connected to the steel casing 4, and the inclined section is connected to the upper end of the straight section and extends into the base 1.

[0051] In this embodiment, the structure of the outer side stress-bearing main reinforcement 5 is specifically described. The outer side stress-bearing main reinforcement 5 includes an inclined section and a straight section, wherein the straight section is connected to the steel casing 4, and the inclined section is connected to the upper end of the straight section and extends into the base 1, which is more in line with the construction specifications of deep water piles.

[0052] In this example, the thickness of the straight section extending into the base 1 is 20 cm.

[0053] like Figure 2 As shown, in some optional embodiments, the upper end of the inclined section faces away from the axis of the steel casing 4.

[0054] In this embodiment, the upper end of the inclined section faces away from the axis of the steel casing 4, which has better stress conditions, facilitates avoiding the inner stressed main reinforcement 31, and complies with the construction specifications of deep water piles.

[0055] like Figure 1 、 Figure 2 and Figure 3 As shown, on the other hand, the present application also provides a deep-water bridge pile foundation structure design method, which is used to design the above-mentioned deep-water bridge pile foundation structure, comprising the following steps:

[0056] Obtaining the design structural parameters of the steel casing 4 and the outer main reinforcement 5, as well as the actual structural parameters of the steel casing 4 under corrosion conditions;

[0057] The set number of the outer main reinforcements 5 is determined based on the design structural parameters of the steel casing 4 and the outer main reinforcements 5, as well as the actual structural parameters of the steel casing 4 under corrosion conditions.

[0058] When designing the deepwater bridge pile foundation structure, the upper side of the cap 1 is used to connect with the pier 2, the pile foundation body 3 is set on the lower side of the cap 1, and the steel casing 4 is sleeved on the outside of the pile foundation body 3 and extends into the cap 1. A set number of outer main reinforcement bars 5 are connected to the outer side of the steel casing 4 and are arranged at intervals along the circumference of the steel casing 4. The upper ends of the outer main reinforcement bars 5 are connected to the cap 1. The set number of outer main reinforcement bars 5 is determined by obtaining the design structural parameters of the steel casing 4 and the outer main reinforcement bars 5, as well as the actual structural parameters of the steel casing 4 under corrosive conditions, and then determining the set number of outer main reinforcement bars 5 based on the design structural parameters of the steel casing 4 and the outer main reinforcement bars 5, as well as the actual structural parameters of the steel casing 4 under corrosive conditions. Since the steel casing 4 extends into the pedestal 1, the upper ends of a set number of outer stress-bearing main reinforcements 5 are connected to the pedestal 1, and the steel casing 4 participates in the permanent stress of the structure, and the set number of outer stress-bearing main reinforcements 5 cooperate with the steel casing 4 and the pile foundation body 3 to participate in the stress. The specific number of outer stress-bearing main reinforcements 5 is derived from the corrosion allowance of the steel casing 4 after considering corrosion, which effectively avoids the problem of steel participating in stress corrosion. The method of adding outer stress-bearing main reinforcements 5 is simpler and more convenient to manufacture, which solves the problem that the design of the cast-in-place pile foundation module for preventing seawater erosion in the existing technology is relatively complex. During actual construction, water-filled water bags need to be arranged on site, and water-filled water bags are used to support the uninitialized concrete pile foundation. The stability of the water-filled water bags needs to be determined through experiments, which increases the construction steps and prolongs the construction period.

[0059] In some optional embodiments, the set number of outer main reinforcement bars 5 is obtained based on the design structural parameters of the steel casing 4 and the outer main reinforcement bars 5, as well as the actual structural parameters of the steel casing 4 under corrosion conditions, including:

[0060] The set number of outer load-bearing main reinforcements 5 is obtained based on the outer diameter of the steel casing 4, the designed wall thickness of the steel casing 4, the wall thickness of the steel casing 4 after corrosion, the design value of the tensile strength of the outer load-bearing main reinforcement 5, the area of ​​a single outer load-bearing main reinforcement 5, and the design value of the tensile strength of the steel.

[0061] In this embodiment, based on the design structural parameters of the steel casing 4 and the outer stress-bearing main reinforcement 5, as well as the actual structural parameters of the steel casing 4 under corrosion conditions, the set number of the outer stress-bearing main reinforcement 5 is obtained, specifically including the outer diameter of the steel casing 4, the design wall thickness of the steel casing 4, the wall thickness of the steel casing 4 after corrosion, the design value of the tensile strength of the outer stress-bearing main reinforcement 5, the area of ​​a single outer stress-bearing main reinforcement 5, and the design value of the tensile strength of the steel, so that the set number of the outer stress-bearing main reinforcement 5 can be quickly obtained.

[0062] In this example, the equivalent single steel bar area generally refers to using the cross-sectional area of ​​one steel bar to replace the total cross-sectional area of ​​multiple smaller diameter steel bars. This is usually used to simplify the reinforcement expression in design or construction. In this solution, the number of outer main bars 5 is obtained by dividing by the area of ​​the equivalent single outer main bar 5.

[0063] In some optional embodiments, according to the formula: The set number of outer main reinforcement bars 5 is obtained;

[0064] Among them, n is the set number of the outer main reinforcement 5, D is the outer diameter of the steel casing 4, d is the wall thickness of the steel casing 4, and d ， is the wall thickness after corrosion, f d is the design value of tensile strength of steel, f sd is the design value of tensile strength of the outer main reinforcement 5, s Δ is the area of ​​a single outer main reinforcement bar 5.

[0065] In this embodiment, according to the formula: The set number of the outer main reinforcement 5 is obtained, where n is the set number of the outer main reinforcement 5, D is the outer diameter of the steel casing 4, d is the wall thickness of the steel casing 4, and d ， is the wall thickness after corrosion, f d is the design value of tensile strength of steel, f sd is the design value of tensile strength of the outer main reinforcement 5, s ΔIn order to represent the area of ​​a single outer main reinforcement 5, the set number of outer main reinforcement 5 can be quickly obtained.

[0066] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships 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, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0067] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0068] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present 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 the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A deep-water bridge pile foundation structure, characterized in that: include: A cap (1), the upper side of which is used to connect with the bridge pier (2); A pile foundation body (3) is arranged on the lower side of the cap (1); A steel casing (4) is sleeved on the outside of the pile foundation body (3) and extends into the cap (1); A set number of outer main stress-bearing ribs (5) are connected to the outer side of the steel casing (4) and are arranged at intervals along the circumference of the steel casing (4); the upper ends of the outer main stress-bearing ribs (5) are connected to the support platform (1).

2. A deepwater bridge pile foundation structure according to claim 1, characterized in that: An inner side main reinforcement (31) is provided in the pile foundation body (3), and the inner side main reinforcement (31) is arranged along the outer circumference of the pile foundation body (3).

3. A deepwater bridge pile foundation structure according to claim 2, characterized in that: Two groups of inner side stress-bearing main reinforcements (31) are provided in the pile foundation body (3), and the two groups of inner side stress-bearing main reinforcements (31) are arranged along a ring shape, and the two groups of inner side stress-bearing main reinforcements (31) are arranged concentrically.

4. A deepwater bridge pile foundation structure according to claim 2 or 3, characterized in that: The distance between the outermost side of the inner stress-bearing main reinforcement (31) and the outer wall of the pile foundation body (3) satisfies the protective layer thickness required by the pile foundation body (3).

5. The deepwater bridge pile foundation structure according to claim 1, characterized in that: The outer main reinforcement (5) is connected to the steel casing (4) by double-sided welding.

6. The deepwater bridge pile foundation structure according to claim 1, characterized in that: The outer main reinforcement (5) includes an inclined section and a straight section, the straight section is connected to the steel casing (4), and the inclined section is connected to the upper end of the straight section and extends into the support platform (1).

7. The deepwater bridge pile foundation structure according to claim 6, characterized in that: The upper end of the inclined section faces a direction away from the axis of the steel casing (4).

8. A method for designing a deepwater bridge pile foundation structure, characterized in that: The method for designing a deep-water bridge pile foundation structure according to any one of claims 1 to 7 comprises the following steps: Obtaining the design structural parameters of the steel casing (4) and the outer main reinforcement (5), and the actual structural parameters of the steel casing (4) under corrosion conditions; The set number of the outer side main reinforcement (5) is determined based on the design structural parameters of the steel casing (4) and the outer side main reinforcement (5), as well as the actual structural parameters of the steel casing (4) under corrosion conditions.

9. A deepwater bridge pile foundation structure design method according to claim 8, characterized in that: The set number of the outer side main reinforcement (5) is obtained based on the design structural parameters of the steel casing (4) and the outer side main reinforcement (5), as well as the actual structural parameters of the steel casing (4) under corrosion conditions, including: The set number of the outer main reinforcement bars (5) is obtained based on the outer diameter of the steel casing (4), the designed wall thickness of the steel casing (4), the wall thickness of the steel casing (4) after corrosion, the design value of the tensile strength of the outer main reinforcement bars (5), the area of ​​a single outer main reinforcement bar (5), and the design value of the tensile strength of the steel.

10. A deepwater bridge pile foundation structure design method according to claim 9, characterized in that: According to the formula: Obtain the set number of outer main reinforcement bars (5); Wherein, n is the set number of the outer main reinforcement (5), D is the outer diameter of the steel casing (4), d is the wall thickness of the steel casing (4), and d ， is the wall thickness after corrosion, f d is the design value of tensile strength of steel, f sd is the design value of tensile strength of the outer main reinforcement (5), s Δ is the area of ​​a single outer main reinforcement (5).

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