Pile foundation and pile foundation repair method

Abstract

This invention discloses a pile foundation and a pile foundation repair method. The pile foundation includes a pile foundation body, an isolating element, and a supporting element. The pile foundation body has a first segment and a second segment in the vertical direction. The first segment is located above the second segment and is connected to it. The first segment is embedded in sand and gravel below the seabed surface. At least a portion of the second segment is located in seawater above the seabed surface. The isolating element is located on the outer periphery of the second segment of the pile foundation and extends in the vertical direction. The lower section of the isolating element is connected to the lower end of the second segment. The pile foundation has a maintenance state and a working state. In the maintenance state, the supporting element is located between the isolating element and the pile foundation body, and both ends of the supporting element are connected to the inner circumferential surface of the isolating element and the outer circumferential surface of the pile foundation body, respectively. This allows the supporting element to be supported by the isolating element, and the isolating element and the second segment of the pile foundation body are spaced apart in the inner and outer directions to form a maintenance compartment. The pile foundation of this invention has the advantages of simple structure, convenient maintenance, and high maintenance efficiency.

Description

Technical Field

[0001] This invention relates to the installation of offshore wind power monopile foundations, wind energy engineering, and new energy fields. Specifically, it relates to a pile foundation and a pile foundation repair method. Background Technology

[0002] Compared to traditional fossil fuels, wind energy is cleaner, lower in cost, and has advantages such as wide development scope, safety, and inexhaustible energy. Compared to onshore wind power, offshore wind power has advantages such as higher wind speeds, lower turbulence, and no occupation of arable land. In my country, offshore wind power foundations mostly use monopile foundations, which are simple to design and have mature installation technology.

[0003] In related technologies, structural inspection and reinforcement of the submerged portion of a monopile foundation cannot be achieved, mainly because it cannot be directly repaired due to environmental factors. Usually, the above problems are prevented by increasing the amount of materials used in the design, which inevitably increases the manufacturing cost of the foundation and is not conducive to cost reduction and efficiency improvement in the offshore wind power industry. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a low-cost pile foundation capable of structural inspection and reinforcement of the underwater portion of the pile foundation.

[0006] This invention provides a simple and convenient method for repairing pile foundations.

[0007] According to an embodiment of the present invention, a pile foundation includes: a pile foundation body having a first segment and a second segment in a vertical direction, the first segment being disposed above the second segment and connected to the second segment, the first segment being embedded in sand and gravel below the seabed surface, and at least a portion of the second segment being located in seawater above the seabed surface; a spacer being disposed on the outer periphery of the second segment of the pile foundation, the spacer extending in a vertical direction, and the lower segment of the spacer being connected to the lower end of the second segment; and a support member having a maintenance state and a working state. In the maintenance state, the support member is disposed between the spacer and the pile foundation body, and both ends of the support member are respectively connected to the inner peripheral surface of the spacer and the outer peripheral surface of the pile foundation body, so that the support member is supported on the spacer, and the spacer and the second segment of the pile foundation body are spaced apart in an inward and outward direction to form a maintenance compartment. In the working state, at least a portion of the inner peripheral surface of the spacer is attached to the outer peripheral surface of the pile foundation body.

[0008] The pile foundation of this invention is equipped with isolation components and support components, which enables structural inspection and reinforcement of the pile foundation in water. Maintenance personnel can directly repair the pile foundation through the maintenance compartment, reducing the manufacturing cost of the pile foundation and helping the offshore wind power industry to reduce costs and increase efficiency.

[0009] In some embodiments, there are multiple support members, all of which are disposed between the isolation member and the pile foundation body. The multiple support members are arranged in multiple rows at intervals along the circumference of the pile foundation body, and each row includes a number of support members spaced apart in the vertical direction.

[0010] In some embodiments, the isolation element includes a plurality of sub-segments arranged sequentially along the circumference of the pile foundation body, each sub-segment being connected below the second segment.

[0011] In some embodiments, the sub-segment has a first side and a second side along the circumference of the foundation pile body. The first side and the second side are respectively provided with a first mounting portion and a second mounting portion. One of the first mounting portion and the second mounting portion is a groove, and the other of the first mounting portion and the second mounting portion is a protrusion. Both the protrusion and the groove extend in the vertical direction. The first mounting portion and the second mounting portion cooperate to connect two adjacent sub-segments.

[0012] In some embodiments, the pile foundation further includes: a sealing ring disposed between the isolator and the pile foundation body to seal the maintenance compartment; and a support frame disposed between the upper end of the isolator and the pile foundation body to support the upper end of the isolator.

[0013] In some embodiments, the isolation element is an airbag or a flexible dry chamber.

[0014] In some embodiments, the inner peripheral surface of the airbag and the outer peripheral surface of the pile foundation body define an inflation chamber. The maintenance state includes a first state and a second state. In the first state, the inflation chamber is inflated so that the airbag and the pile foundation body are spaced apart in the inward and outward directions to install the support member. In the second state, the gas in the airbag is released so that the pressure inside the inflation chamber is equal to atmospheric pressure for maintenance of the pile foundation body.

[0015] In some embodiments, the airbag includes a connected inner layer and an outer layer defining a closed inflatable chamber. In the maintenance state, the airbag inflates and the inner layer of the airbag and the pile foundation are spaced apart in an inward-outward direction to define the maintenance chamber.

[0016] In some embodiments, during the maintenance state, the cross-sectional area of ​​the maintenance compartment gradually increases from bottom to top.

[0017] According to the pile foundation repair method of the present invention, using the pile foundation described in any one of the above-mentioned embodiments, the method includes: S1: a plurality of flexible dry chambers are sequentially arranged on the outer circumferential surface of the pile foundation along the circumference of the pile foundation; S2: a plurality of support members are spaced apart in the vertical direction between the flexible dry chambers and the pile foundation, and the two ends of the plurality of support members are respectively connected to the inner circumferential surface of the flexible dry chamber and the outer circumferential surface of the pile foundation, so that the support members are supported between the flexible dry chambers and the pile foundation, and the support members are supported by the flexible dry chambers to define an inspection chamber; S3: maintenance personnel enter the inspection chamber to perform structural inspection and reinforcement on the pile foundation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the pile foundation according to an embodiment of the present invention.

[0019] Figure 2 This is a top view of the pile foundation according to an embodiment of the present invention.

[0020] Figure 3 This is a structural schematic diagram of a sub-segment of a pile foundation according to an embodiment of the present invention.

[0021] Figure 4 This is a schematic diagram of the installation of a pile foundation according to an embodiment of the present invention.

[0022] Pile foundation 100;

[0023] Pile foundation body 1; Section 11; Section 2;

[0024] Isolator 2; Sub-segment 21; First mounting section 211; Second mounting section 212; Inspection compartment 22;

[0025] Support component 3; support frame 4; sealing ring. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] The following description of a pile foundation according to an embodiment of the present invention is based on the accompanying drawings.

[0028] like Figure 1-4 As shown, the pile foundation 100 according to an embodiment of the present invention includes a pile foundation body 1, a separator 2, and a support 3.

[0029] The pile foundation body 1 has a first segment 11 and a second segment 12 in the vertical direction. The first segment 11 is located above the second segment 12 and is connected to the second segment 12. The first segment 11 is embedded in the sand and gravel below the seabed surface, and at least a portion of the second segment 12 is located in the seawater above the seabed surface. Specifically, as shown... Figure 1-4 As shown, the pile foundations 100 are all hollow cylindrical structures. The seabed surface is the interface between seawater and bottom sand and gravel. The second section 12 is the upper part of the pile foundation 100 located in the seawater above the seabed surface, and the first section 11 is the lower part of the pile foundation 100 buried in the sand and gravel below the seabed surface, thereby fixing the pile foundation 100 at sea.

[0030] The isolation element 2 is located on the outer periphery of the second section 12 of the pile foundation 100. The isolation element 2 extends vertically, and its lower section is connected to the lower end of the second section 12. The pile foundation 100 has a maintenance state and a working state. In the maintenance state, the support element 3 is located between the isolation element 2 and the pile foundation body 1, and both ends of the support element 3 are connected to the inner peripheral surface of the isolation element 2 and the outer peripheral surface of the pile foundation body 1, respectively, so that the support element 3 supports the isolation element 2. The isolation element 2 and the second section 12 of the pile foundation body 1 are spaced apart in the inner and outer directions to form a maintenance compartment 22. In the working state, at least a portion of the inner peripheral surface of the isolation element 2 is attached to the outer peripheral surface of the pile foundation body 1. Specifically, as shown... Figure 1-2 As shown, when the pile foundation 100 needs maintenance, the isolation member 2 is located on the outer periphery of the second section 12 of the pile foundation body 1, and the support member 3 is installed between the isolation member 2 and the pile foundation body 1. Thus, the isolation member 2 is supported on the pile foundation body 1 by the support member 3, so that the pile foundation body 1 is separated from the seawater by the isolation member 2 and forms a maintenance chamber 22, allowing workers to enter the maintenance chamber 22 to maintain the pile foundation body 1. When the pile foundation 100 is working normally, the support member 3 can be retracted or removed from the isolation member 2. At this time, the isolation member 2 is in contact with the pile foundation body 1, and the pile foundation body 1 is working normally.

[0031] In this embodiment of the invention, the pile foundation 100 has an isolation member 2 on the outer periphery of the second section 12. When it is necessary to inspect the second section 12 of the pile foundation body 1, the isolation member 2 will form an inspection chamber 22 on the outer periphery of the pile foundation body 1, thereby facilitating the inspection of the outer periphery of the pile foundation body 1 by maintenance personnel. This achieves reinforcement of the underwater structure of the single pile foundation 100 during its service life, reduces costs and increases efficiency, and further extends the foundation life.

[0032] In some embodiments, there are multiple support members 3, all of which are disposed between the isolation member 2 and the pile foundation body 1. The multiple support members 3 are arranged in multiple rows at intervals along the circumference of the pile foundation body 1, and each row includes several support members 3 spaced apart in the vertical direction. Thus, the isolation member 2 located in seawater is supported by multiple support members 3, ensuring the support efficiency of the support members 3 and improving the stability of the isolation member 2.

[0033] In some embodiments, the inner circumferential surface of the isolator 2 and the outer circumferential surface of the pile foundation 100 are both provided with a first mating part (not shown in the figure), and the two ends of the support member 3 are provided with a second mating part (not shown in the figure) that mates with the first mating part. One of the first mating part and the second mating part is a protrusion, and the other of the first mating part and the second mating part is a groove. The second mating part is located above the first mating part and mates with the first mating part so that the support member 3 is installed between the isolator 2 and the pile foundation body 1, which facilitates the installation and disassembly of the support member 3.

[0034] It is worth noting that the support member 3 can be any kind of support rod, I-beam, support plate, etc., and the two ends of the support member 3 can be installed between the isolation member 2 and the pile foundation body 1 by any of the following methods: snap-fit, fastener connection, adhesive bonding, etc.

[0035] In some embodiments, the isolation member 2 includes a plurality of sub-segments 21 arranged sequentially along the circumference of the pile foundation body 1, each sub-segment 21 being connected below the second segment 12. Specifically, as shown... Figure 1-2 As shown, each segment 21 is generally elongated and extends in the vertical direction. Multiple segments 21 are arranged sequentially along the circumference of the pile foundation body. The lower end of each segment 21 is fixedly installed at the lower end of the second segment 12. The two sides of each segment 21 are connected to the adjacent segments 21. Multiple segments 21 surround the outer periphery of the pile foundation body 1. Each segment 21 is provided with at least one row of support members 3. Thus, the installation and manufacturing cost of the isolation member 2 is reduced by using the combined isolation member 2.

[0036] In some embodiments, such as Figure 3 As shown, a first mounting part 211 and a second mounting part 212 are respectively provided on both sides of the sub-segment 21. Both the first mounting part 211 and the second mounting part 212 are made of rubber, and one of the first mounting part 211 and the second mounting part 212 is a groove, while the other of the first mounting part 211 and the second mounting part 212 is a protrusion. Both the protrusion and the groove extend in the vertical direction, and the protrusion can pass through the groove. This allows two adjacent sub-segments 21 to be connected through the first mounting part 211 and the second mounting part 212. The first mounting part 211 and the second mounting part 212 also ensure the sealing performance of the maintenance compartment 22, preventing seawater from flowing into the maintenance compartment 22 through the two adjacent sub-segments 21.

[0037] In some embodiments, the pile foundation 100 further includes a sealing ring and a support frame 4.

[0038] A sealing ring 5 is positioned between the isolating element 2 and the pile foundation body 1 to seal the maintenance compartment 22. A support frame 4 is positioned between the upper end of the isolating element 2 and the pile foundation body 1 to support the upper end of the isolating element 2. Specifically, as shown... Figure 1 As shown, the sealing ring 5 can be a sealing ring, which is sleeved on the outer circumferential surface of the lower end of the second section 12 of the pile foundation body 1. The lower end of the isolation member 2 is located on the outer circumferential surface of the sealing ring. Thus, the sealing ring seals the lower end of the isolation member 2 and the lower end of the pile foundation body 1, preventing seawater from entering the maintenance compartment 22. The support frame 4 is located between the inner circumferential surface of the upper end of the isolation member 2 and the inner circumferential surface of the upper end of the second section 12 of the pile foundation body 1. In other words, the support frame 4 is installed at the opening of the maintenance compartment 22, thereby supporting the opening of the maintenance compartment 22 and facilitating maintenance personnel to enter the maintenance compartment 22 through the opening.

[0039] In some embodiments, when installing the sealing ring 5, the sealing ring 5 can be sleeved on the lower end of the second section 12 of the pile foundation body 1 and installed on the outer end face of the lower end of the second section 12 of the pile foundation body 1 by fasteners or adhesive. Then, the isolation member 2 is fixed to the outer circumferential surface of the sealing ring 5 by adhesive or fasteners. Alternatively, after the isolation member 2 is assembled in seawater, the sealing ring 5 is inserted between the pile foundation body 1 and the isolation member 2 and fixed by fasteners, so that the sealing ring is installed on the pile foundation body 1 and the isolation member 2.

[0040] In some embodiments, the isolation element 2 is an airbag or a flexible dry chamber. Thus, the isolation element 2 can be selected according to actual needs, such as when the isolation element 2 is an airbag or a flexible dry chamber.

[0041] In some embodiments, the inner circumferential surface of the airbag and the outer circumferential surface of the pile foundation body 1 define an inflation chamber. The maintenance state includes a first state and a second state. In the first state, the inflation chamber expands so that the airbag and the pile foundation body 1 are spaced apart in the inward and outward directions to install the support member 3. In the second state, the gas in the airbag is released so that the pressure inside the inflation chamber is equal to atmospheric pressure for maintenance of the pile foundation body 1. Specifically, the airbag is a single layer and is installed on the outer circumferential surface of the pile foundation body 1 (at this time, the maintenance chamber 22 and the inflation chamber share a cavity). The lower end of the airbag is fixedly installed on the outer circumferential surface of the lower end of the second section 12 of the pile foundation body. In the first state, the upper end of the airbag is closed to the outer circumferential surface of the second section 12 of the pile foundation body 1 (in other words, the opening of the maintenance chamber 22 is closed) to inflate the inflation chamber. When the airbag expands to a preset volume, maintenance personnel wearing high-pressure protective clothing enter the inflation chamber to install the support member 3 inside the maintenance chamber 22, thereby ensuring the stability of the maintenance chamber 22.

[0042] In some embodiments, the airbag includes an inner layer and an outer layer connected together, defining a closed inflatable chamber. In the maintenance state, the airbag inflates, and the inner layer of the airbag and the pile foundation 100 are spaced apart in the inward and outward directions to define a maintenance chamber 22. Specifically, the airbag is a double-layered airbag composed of an inner layer and an outer layer. The lower end of the airbag is fixedly installed on the outer peripheral surface of the lower end of the second section 12 of the pile foundation body, and the airbag surrounds the outer peripheral side of the pile foundation body. When maintenance is required, high-pressure gas is injected into the airbag to inflate it, so that the inner peripheral surface of the airbag and the outer peripheral surface of the second section 12 of the pile foundation body are spaced apart in the inward and outward directions to form a maintenance chamber 22. After the water in the maintenance chamber 22 is pumped out by a water pump, maintenance personnel enter the maintenance chamber 22 and install the support member 3 inside the maintenance chamber 22 to support the maintenance chamber 22 and ensure the stability of the maintenance chamber 22 during the maintenance process.

[0043] In some embodiments, during maintenance, the cross-sectional area of ​​the maintenance compartment 22 gradually increases from bottom to top. This facilitates maintenance personnel entering the maintenance compartment 22 to inspect the pile foundation 100, making the pile foundation 100 more rationally positioned.

[0044] like Figure 4 As shown, the method for repairing a pile foundation 100 according to an embodiment of the present invention is characterized in that, utilizing the pile foundation 100 of any of the above embodiments, it includes:

[0045] S1: Multiple flexible dry chambers are sequentially arranged along the circumference of the pile foundation 100 on the outer circumferential surface of the pile foundation 100. Specifically, as follows: Figure 4 As shown, multiple flexible dry chambers are sequentially installed on the outer circumferential surface of the second section 12 of the outer circumferential surface of the pile foundation body 1 along the circumferential direction of the pile foundation body 1, and the lower end of the flexible dry chamber is installed on the outer circumferential surface of the lower end of the second section 12 of the pile foundation body 1 through a sealing ring, so that multiple flexible dry chambers surround the pile foundation 100.

[0046] S2: Multiple support members 3 are spaced vertically between the flexible dry chamber and the pile foundation 100, with both ends of the support members 3 connected to the inner circumferential surface of the flexible dry chamber and the outer circumferential surface of the pile foundation 100, respectively. This allows the support members 3 to support the flexible dry chamber and the pile foundation 100, thus defining the maintenance compartment 22 within the flexible dry chamber. Specifically, the installation of the support members 3 can be selected according to actual needs. For example, maintenance personnel can enter the area between the flexible dry chamber and the pile foundation 100 and fix the support members 3 between them, thereby supporting the flexible dry chamber and the pile foundation 100. Alternatively, the upper end of the flexible dry chamber and the upper end of the pile foundation 100 can be sealed, and the flexible dry chamber can be inflated. After the flexible dry chamber expands, maintenance personnel wearing high-pressure protective suits can enter the maintenance compartment 22 from above and install the support members 3 between the flexible dry chamber and the pile foundation 100.

[0047] S3: Maintenance personnel enter the maintenance compartment 22 to conduct structural inspections and reinforcement of the pile foundation 100. Thus, after the support component 3 is installed, the upper end of the flexible dry compartment and the upper end of the pile foundation 100 are opened and the support frame 4 is installed, and the maintenance personnel begin to inspect and reinforce the pile foundation 100.

[0048] The pile foundation repair method of this invention has the advantages of simple steps, convenient maintenance, and low cost.

[0049] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0053] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0054] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A pile foundation, characterized in that, include: The pile foundation body has a first section and a second section in the vertical direction. The first section is located above the second section and is connected to the second section. The first section is embedded in the sand and gravel below the seabed surface, and at least a part of the second section is located in the seawater above the seabed surface. The isolation element is disposed on the outer periphery of the second section of the pile foundation, the isolation element extends in the vertical direction, and the lower section of the isolation element is connected to the lower end of the second section; The support member of the pile foundation has a maintenance state and a working state. In the maintenance state, the support member is disposed between the isolation member and the pile foundation body, and both ends of the support member are respectively connected to the inner circumferential surface of the isolation member and the outer circumferential surface of the pile foundation body, so that the support member is supported on the isolation member and the second section of the isolation member and the pile foundation body are spaced apart in the inward and outward directions to form a maintenance compartment. In the working state, at least a portion of the inner circumferential surface of the isolation member is attached to the outer circumferential surface of the pile foundation body. The isolation component is an airbag or a flexible dry chamber; The airbag inflates to form the maintenance compartment.

2. The pile foundation according to claim 1, characterized in that, There are multiple support members, all of which are disposed between the isolation member and the pile foundation body. The multiple support members are arranged in multiple rows at intervals along the circumference of the pile foundation body, and each row includes several support members arranged at intervals along the vertical direction.

3. The pile foundation according to claim 1, characterized in that, The isolation element comprises multiple sub-segments arranged sequentially along the circumference of the pile foundation body, each sub-segment being connected to the lower part of the second segment.

4. The pile foundation according to claim 3, characterized in that, The sub-segment has a first side and a second side along the circumference of the pile foundation body. The first side and the second side are respectively provided with a first mounting part and a second mounting part. One of the first mounting part and the second mounting part is a groove, and the other of the first mounting part and the second mounting part is a protrusion. Both the protrusion and the groove extend in the vertical direction. The first mounting part and the second mounting part cooperate to connect two adjacent sub-segments.

5. The pile foundation according to claim 1, characterized in that, Also includes: A sealing ring is disposed between the isolation element and the pile foundation body to seal the maintenance compartment; A support frame is provided between the upper end of the isolating member and the pile foundation body so that the support frame supports the upper end of the isolating member.

6. The pile foundation according to claim 5, characterized in that, The inner circumferential surface of the airbag and the outer circumferential surface of the pile foundation body define an inflation chamber. The maintenance state includes a first state and a second state. In the first state, the inflation chamber is inflated so that the airbag and the pile foundation body are spaced apart in the inward and outward directions to install the support member. In the second state, the gas in the airbag is released so that the pressure inside the inflation chamber is equal to atmospheric pressure for maintenance of the pile foundation body.

7. The pile foundation according to claim 1, characterized in that, The airbag includes an inner layer and an outer layer connected together, the inner layer and the outer layer defining a closed inflatable chamber. In the maintenance state, the airbag inflates and the inner layer of the airbag and the pile foundation are spaced apart in the inward and outward directions to define the maintenance chamber.

8. The pile foundation according to any one of claims 1-5, characterized in that, In the maintenance state, the cross-sectional area of ​​the maintenance compartment gradually increases from bottom to top.

9. A method for repairing pile foundations, characterized in that, The pile foundation according to any one of claims 1-8 comprises: S1: Multiple flexible dry chambers are sequentially arranged on the outer circumferential surface of the pile foundation along the circumference of the pile foundation; S2: Multiple support members are spaced apart in the vertical direction between the flexible dry chamber and the pile foundation, and the two ends of the multiple support members are respectively connected to the inner peripheral surface of the flexible dry chamber and the outer peripheral surface of the pile foundation, so that the support members are supported between the flexible dry chamber and the pile foundation, and the support members are supported in the flexible dry chamber to define the maintenance compartment. S3: Maintenance personnel enter the maintenance compartment to conduct structural inspections and reinforcements on the pile foundation.

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