CN112240030B

CN112240030B - Offshore wind power combined single-pile foundation and construction method thereof

Info

Publication number: CN112240030B
Application number: CN202011260348.6A
Authority: CN
Inventors: 王天鹏; 张洁; 肖诗豪
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2020-11-12
Filing date: 2020-11-12
Publication date: 2021-12-07
Anticipated expiration: 2040-11-12
Also published as: CN112240030A

Abstract

The invention relates to an offshore wind-power combined single pile foundation and a construction method thereof. Compared with the prior art, the method can solve the problem of vertical deviation rectification of the single-pile foundation to a certain extent, improves the applicability of the single-pile foundation in the deep sea area, and has the advantages of high anti-overturning capacity, high bearing capacity, convenience in construction, good economic benefit and the like.

Description

Offshore wind power combined single-pile foundation and construction method thereof

Technical Field

The invention belongs to the technical field of offshore wind power foundations, and relates to an offshore wind power combined single-pile foundation and a construction method thereof.

Background

Energy is the basis of modern society and economic development, however, with the increase of population and the increasing development of social economy, the consumption of energy is also rapidly increased, and the energy crisis is gradually appeared. The development of clean and efficient renewable energy is a strategic target of vigorous development of all countries in the world, and wind energy is one of the important new energy sources developed by all countries as renewable energy. The offshore wind power generation is one of wind power utilization, is developed rapidly in recent years, has most advantages of onshore wind power generation, and has the advantages of large power generation amount, less use limitation, no land occupation and the like.

The major diameter single pile basis is the mainstream of offshore wind power basis, and construction convenience and economic benefits are better, but the single pile basis is generally suitable for the sea area that the depth of water is less than 25m, and along with the development gradually of coastal waters wind power resource, deep water sea area wind power development is trend greatly, and the problem that restricts the application of single pile basis to deep water sea area mainly has: the single pile foundation needs to have larger bearing capacity and anti-skid and anti-overturning stability; when the construction ship is used for pile sinking construction, the verticality of a single pile is difficult to control due to the influence of waves, sea wind and the like; the large-diameter single-pile foundation material has large use amount, inconvenient carrying and the like.

In the event of a claim for an offshore wind power project, the problems associated with a single pile foundation account for 35%, most of which occur in deep sea areas. This is due in part to the fact that developers still employ a basic monopile foundation in the construction process to reduce costs, regardless of reliability and applicability. At present, various types of offshore wind power foundations are reliably combined, so that the offshore wind power foundations have the combined advantages of various types of foundations, and the offshore wind power foundations are a trend of development of offshore wind power foundations in the future. Therefore, the development of a novel durable combined single-pile foundation is of great significance.

Disclosure of Invention

The invention aims to provide an offshore wind power combined single-pile foundation and a construction method thereof, and aims to solve the problems that a basic single-pile foundation is poor in reliability and applicability in a deep sea area, pile sinking verticality is difficult to guarantee and the like. Has the advantages of high anti-overturning capacity, high bearing capacity, convenient construction, good economic benefit and the like.

The purpose of the invention can be realized by the following technical scheme:

on the one hand, marine combined type single pile basis of wind-power generation, including steel-pipe pile and a plurality of variable cross section T type pterygoid lamina, the surface of steel-pipe pile along vertical being equipped with quantity match the mortise slot of variable cross section T type pterygoid lamina, variable cross section T type pterygoid lamina on be equipped with the tenon that mortise slot matches for through the mortise and tenon structure fixed connection who comprises mortise slot and tenon between variable cross section T type pterygoid lamina and the steel-pipe pile.

Further, the bottom of the steel pipe pile is connected with a pile tip. Furthermore, the pile tip is in an opening shape, a cross shape, a quadrangular pyramid shape, a hexagonal pyramid shape or a conical shape. The welding seal between the pile tip and the bottom end of the steel pipe pile is ensured so as to prevent the mud from entering the pile bottom and entering water.

Further, the outer diameter of the steel pipe pile is selected to be 3-5m, the wall thickness is 0.3-1mm, the height is 20-50m, the longitudinal length (namely the vertical direction) of the mortise slot arranged on the outer side of the steel pipe pile is 10-30m, the steel pipe pile is generally prefabricated on the land, meanwhile, the mortise slot is generally welded on the steel pipe pile in advance, and the welding quality is ensured. Generally, the mortise slots are preferably arranged into 4 slots, and are uniformly welded on the steel pipe pile.

Furthermore, a stiffening rib with a full length is arranged in the steel pipe pile, and the stiffening rib can be in a cross shape, a straight shape or other shapes and is used for improving the bending rigidity of the steel pipe pile.

Furthermore, the variable cross-section T-shaped wing plate is composed of a web plate and a flange which are mutually and vertically connected, wherein the tenon is arranged on the web plate, the length (namely the width along the radial direction of the steel pipe pile) of the web plate is gradually reduced from top to bottom, and the variable cross section of the T-shaped flange from top to bottom is realized, so that the whole web plate is in a right trapezoid shape or a right triangle shape with a large top and a small bottom.

The web plate can effectively improve the bending rigidity and the bearing capacity of the steel pipe pile, reduce the material and the size of the steel pipe pile, and further, the thickness of the web plate is 0.2-0.5m, the height of the web plate is 0.2-2m, the height-thickness ratio is not too large, and the local stability requirement is met.

The thickness of the flange is 0.2-0.5m, the width is 0.5-1m, the width-thickness ratio is not too large, and the requirement of local stability is met.

Furthermore, a groove which is communicated up and down is formed in one end, far away from the steel pipe pile, of the web plate, a protrusion which can be inserted into the groove in a matched mode is vertically arranged in the middle of the flange, the groove is rotatably connected with the bottom of the protrusion, a driving telescopic piece is further arranged in the groove, and two ends of the driving telescopic piece are hinged to the bottom of the groove and the protrusion respectively. Still further preferably, the active telescopic part is a jack; the groove is rotatably connected with the bottom of the bulge through a large-diameter bolt. Therefore, the variable cross-section T-shaped wing plate can form a mechanical structure for assisting vertical deviation correction of the sinking pile by matching with a plumb instrument, a strain sensor, an acceleration sensor and the like additionally arranged through the active telescopic part, when the deviation of one side of the corresponding steel pipe pile body excessively deviates, the active telescopic part (namely a jack) in the variable cross-section T-shaped wing plate corresponding to the side is started, and thus, the flange of the variable cross-section T-shaped wing plate is contacted with the foundation to generate a reaction force, so that the steel pipe pile body returns to the right direction in the opposite direction, and the purpose of correcting the deviation is achieved. And the plumb gauge, the strain sensor, the acceleration sensor and the like are responsible for monitoring the verticality, the speed, the depth and the like in the pile sinking process during pile sinking, and the vertical deviation correcting device is controlled according to the reflected pile sinking condition.

Furthermore, the tenon-and-mortise structure is reinforced by high-strength bolts.

On the other hand, the invention also provides a construction method of the offshore wind power combined single-pile foundation, which comprises the following steps:

(1) prefabricating components including the steel pipe pile and the variable cross-section T-shaped wing plate;

(2) all the components are conveyed to a construction site, and then the steel pipe pile and the variable cross-section T-shaped wing plate are combined into a single-pile foundation through a mortise and tenon structure;

(3) hoisting and sinking the single-pile foundation to a designed pile position, sinking the pile after stabilizing the pile, and controlling the verticality to reach the standard in the pile sinking process;

(4) and after the pile is sunk to the designed elevation, checking the bearing capacity of the single-pile foundation and reinforcing the foundation to finish the process.

Furthermore, after the pile is sunk to the designed elevation, the sinking condition of the variable cross-section T-shaped wing plate is checked, and if a large gap exists between the flange and the steel pipe pile after sinking, stacking and carrying objects are preferably filled in the gap to reinforce the single pile foundation.

Compared with the prior art, the invention has the following advantages:

(1) the single-pile foundation has higher bearing capacity and anti-overturning capacity so as to meet the reliability requirement of deep sea areas;

(2) the technical problem that the verticality is difficult to guarantee when a single-pile foundation is sunk can be solved, the construction efficiency of the offshore wind power single-pile foundation sinking pile can be effectively improved, the use of ship equipment is reduced, and the construction cost is reduced;

(3) the combined single-pile foundation is relatively convenient to carry, the material consumption of the steel pipe pile can be obviously saved through the variable-section T-shaped wing plate, and the cost is saved.

Drawings

Fig. 1 is a schematic perspective view of a single pile foundation according to the present invention;

fig. 2 is a schematic perspective view of a single-pile foundation pile bottom provided by the present invention;

fig. 3 is a schematic perspective view of a single pile foundation pile top provided by the present invention;

FIG. 4 is a front view of a variable cross-section T-shaped wing of the present invention;

fig. 5 is a top view of the variable cross-section T-shaped wing according to the present invention.

The notation in the figure is:

the method comprises the following steps of 1-steel pipe pile, 2-variable cross-section T-shaped wing plate, 21-web plate, 22-flange, 3-pile tip, 4-stiffening rib, 5-mortise and tenon joint structure, 51-tenon joint, 52-mortise and tenon joint groove, 6-bulge, 7-large-diameter bolt, 8-jack and 9-groove.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

For convenience of description, the words "up", "down", "left" and "right" in the present invention, if any, merely indicate correspondence with up, down, left and right directions of the drawings themselves, and do not limit the structure, but merely facilitate the description of the invention and simplify the description, rather than indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.

Although the basic single-pile foundation is convenient to construct and good in economic benefit, the applicable water depth is shallow, the reliability and the applicability in the deep sea area are poor, the verticality of the pile sinking is difficult to guarantee, and the development of a novel single-pile foundation for overcoming the problem of the basic single-pile foundation in the deep sea area is of great significance.

In order to solve the above problems, in one aspect, the invention provides an offshore wind power combined single pile foundation, as shown in fig. 1 to 5, including a steel pipe pile 1 and a plurality of variable cross-section T-shaped wing plates 2, the outer surface of the steel pipe pile 1 is vertically provided with a number of mortise slots 52 matching the variable cross-section T-shaped wing plates 2, the variable cross-section T-shaped wing plates 2 are provided with tenons 51 matching the mortise slots 52, so that the variable cross-section T-shaped wing plates 2 and the steel pipe pile 1 are fixedly connected through a mortise structure 5 composed of the mortise slots 52 and the tenons 51.

In a specific embodiment, referring to fig. 2 again, a pile tip 3 is further connected to the bottom of the steel pipe pile 1. In more specific embodiments, the pile tip 3 is open, cross, quadrangular pyramid, hexagonal pyramid, or conical. The welding seal between the pile tip 3 and the bottom end of the steel pipe pile 1 is ensured to prevent the mud from entering the pile bottom and entering water.

In a specific embodiment, the steel pipe pile 1 has an outer diameter of 3-5m, a wall thickness of 0.3-1mm, a height of 20-50m, and a longitudinal length (i.e. vertical direction) of the mortise 52 formed at the outer side of the steel pipe pile 1 of 10-30m, and the steel pipe pile 1 is generally prefabricated on land, and the mortise 52 is generally pre-welded to the steel pipe pile 1 to ensure welding quality. Generally, the number of the mortise slots 52 is preferably 4, and the mortise slots are uniformly welded to the steel pipe pile 1.

In a specific embodiment, please refer to fig. 3 and the like, a stiffening rib 4 having a full length is further disposed inside the steel pipe pile 1, and the stiffening rib 4 may be cross-shaped, straight-shaped, or other shapes, and is used for improving the bending rigidity.

In a specific embodiment, please refer to fig. 4 and the like again, the variable-section T-shaped wing plate 2 is composed of a web 21 and a flange 22 which are connected perpendicularly to each other, wherein the tenon 51 is disposed on the web 21, and the length of the web 21 (i.e. the width along the radial direction of the steel pipe pile 1) is gradually reduced from top to bottom, so that the "variable section" of the T-shaped flange 22 from top to bottom is realized, so that the whole web 21 is in a right-angled trapezoid or a right-angled triangle with a large top and a small bottom, and the like.

The web plate 21 can effectively improve the bending rigidity and the bearing capacity of the steel pipe pile 1, reduce the material and the size of the steel pipe pile 1, and further, the thickness of the web plate 21 is 0.2-0.5m, the height is 0.2-2m, the height-thickness ratio is not too large, and the local stability requirement is met.

The thickness of the flange 22 is 0.2-0.5m, the width is 0.5-1m, the width-thickness ratio is not too large, and the requirement of local stability is met.

In a more specific embodiment, please refer to fig. 5 and the like again, a groove 9 penetrating up and down is formed in one end of the web 21 away from the steel pipe pile 1, a protrusion 6 capable of being inserted into the groove 9 is vertically arranged in the middle of the flange 22, the groove 9 is rotatably connected with the bottom of the protrusion 6, an active telescopic member is further arranged in the groove 9, and two ends of the active telescopic member are respectively hinged to the bottom of the groove 9 and the protrusion 6. Still more preferably, the active telescopic part is a jack 8; the bottom positions of the groove 9 and the protrusion 6 are rotatably connected through a large-diameter bolt 7 (the large-diameter bolt 7 does not limit the diameter, and only requires the diameter or strength to meet corresponding requirements, so that the flange 22 and the web 21 cannot be damaged during relative rotation). Therefore, the mechanical structure for assisting vertical deviation correction of the sinking pile can be formed by matching the active telescopic part with a plumb instrument, a strain sensor, an acceleration sensor and the like additionally arranged, when the deviation of the corresponding steel pipe pile 1 is excessively deviated to one side to be corrected, the active telescopic part (namely a jack 8) in the variable cross section T-shaped wing plate 2 corresponding to the side is opened, and thus, the flange 22 of the variable cross section T-shaped wing plate 2 is contacted with the foundation to generate reaction force so that the pile body of the steel pipe pile 1 returns to the right direction in the opposite direction, and the purpose of correcting the deviation is achieved. And the plumb gauge, the strain sensor, the acceleration sensor and the like are responsible for monitoring the verticality, the speed, the depth and the like in the pile sinking process during pile sinking, and the vertical deviation correcting device is controlled according to the reflected pile sinking condition.

In a specific embodiment, the tenon-and-mortise structure 5 is further reinforced by high-strength bolts (the high strength here is not limited to the strength, and is only to indicate that the strength needs to meet the reinforcement requirement).

(1) prefabricating components including a steel pipe pile 1 and a variable cross-section T-shaped wing plate 2;

(2) all the components are conveyed to a construction site, and then the steel pipe pile 1 and the variable cross-section T-shaped wing plate 2 are combined into a single-pile foundation through a mortise and tenon structure 5;

Further, after the pile is sunk to the designed elevation, the sinking condition of the variable cross-section T-shaped wing plate 2 is checked, and if a large gap exists between the flange 22 and the steel pipe pile 1 after sinking, stacking and carrying objects are preferably filled in the gap to reinforce the single-pile foundation.

The above embodiments may be implemented individually, or in any combination of two or more.

In order to further understand the contents, features and effects of the present invention, the following examples are given.

Example 1:

as shown in fig. 1 to 5, the combined single-pile foundation comprises a steel pipe pile 1 with a mortise 52, four variable cross-section T-shaped wing plates 2 with tenons 51, a flat-bottom open pile tip 3, a through-long cross-shaped stiffening rib 4, a reliably connected tenon-and-mortise structure 5 which is easy to form, auxiliary vertical deviation-rectifying mechanical parts (including a jack 8 and the like) in a pile sinking process, a large-diameter bolt 7 positioned at the bottom end of the variable cross-section T-shaped wing plate 2, and the jack 8.

As shown in fig. 1, the steel pipe pile 1 is provided with four longitudinal mortise slots 52 so as to be reliably connected with the variable cross-section T-shaped wing plate 2 with the tenon 51, the bottom end of the steel pipe pile 1 is preferably welded with the flat-bottom open type pile tip 3 in advance on land to assist pile sinking, and the steel pipe pile 1 is internally provided with a full-length cross-shaped stiffening rib 4 so as to improve the bending rigidity of a single pile foundation and improve the bearing capacity. The steel pipe pile 1 and the components thereof are hot rolled or cold bent on land to form a combined member. The four variable cross-section T-shaped wing plates 2 are provided with tenons 51; the jack 8 of the vertical deviation rectifying mechanical structure is arranged inside the variable cross-section T-shaped wing plate 2 and is used for linking data to a pile sinking console so as to apply reverse thrust during vertical deviation rectifying of the pile sinking; the large-diameter bolt 7 is arranged at the bottom end of the variable cross-section T-shaped wing plate 2, so that the vertical deviation rectifying mechanical structure can rotate around the bottom as an axis when being opened and closed, and a good deviation rectifying effect is achieved. The variable cross-section T-shaped wing plate 2 and the parts thereof are used as another combined component, and a combined single-pile foundation is formed by connecting the combined component with high-strength bolts through a mortise and tenon structure 5 before pile sinking.

To further illustrate the present disclosure, the dimensions of the associated components of the monopile foundation are enumerated. The outer diameter of the steel pipe pile 1 can be selected from 3m to 5m, the wall thickness can be selected from 0.3m to 1m, the height can be selected from 20 m to 50m, the longitudinal length of the tenon-and-mortise structure 5 arranged on the steel pipe pile can be selected from 10m to 30m, the section size is determined according to welding requirements, the longitudinal length is related to the embedding depth of the pile, the number is preferably 4, the longitudinal length is taken as a modulus, the longitudinal length and the embedding depth are uniformly welded on the steel pipe pile 1, and the specific size of the steel pipe pile 1 is determined according to design purposes and engineering environments.

As shown in fig. 2, the type of the pile tip 3 can be cross type, open type, quadrangular pyramid type, hexagonal pyramid type, cone type, etc., and should be welded with the bottom end of the single pile in advance. As shown in fig. 3, the cross stiffening ribs 4 with full length are welded in the steel pipe pile 1 in advance, the thickness can be 0.1-0.3m, and the stiffening ribs 4 such as a straight line can also be adopted, which is determined according to the engineering requirements. The web plate 21 of the variable cross-section T-shaped wing plate 2 can effectively improve the bending rigidity and the bearing capacity of the steel pipe pile 1, reduce the materials and the size of the steel pipe pile 1, and the thickness of the variable cross-section T-shaped wing plate can be selected from 0.2 to 0.5m, the height of the variable cross-section T-shaped wing plate can be selected from 0.2 to 2m, the height-thickness ratio is not too large, the thickness of the flange 22 can be selected from 0.2 to 0.5m, the width can be selected from 0.5 to 1m, and the width-thickness ratio is not too large, so that the local stability requirement can be met. The variable cross-section T-shaped wing plate 2 can be manufactured on land by adopting a cold bending or hot rolling process, the inclination angle of the web plate 21 can be 60-80 degrees, so that the steel pipe pile 1 is easy to sink, and the end part of the variable cross-section T-shaped wing plate is made into a tenon 51 corresponding to the mortise 52 on the steel pipe pile 11. The diameter of the large-diameter bolt 7 at the bottom end of the variable cross-section T-shaped wing plate 2 can be selected to be 0.1-0.3 m.

As shown in fig. 4 and 5, the embodiment further provides a mechanical structure for assisting vertical deviation correction of pile sinking, which effectively solves the technical problem that the verticality is difficult to guarantee when a single-pile foundation is sunk, and the mechanical structure comprises a variable cross-section T-shaped wing plate 2 with a jack 8 arranged inside, a plumb bob instrument, a strain sensor, an acceleration sensor and the like. When the deviation of the pile body of the steel pipe pile 1 to one side excessively needs to be corrected, the built-in jack 8 of the variable cross-section T-shaped wing plate 2 on the side is opened, and the flange 22 of the variable cross-section T-shaped wing plate 2 is in contact with the foundation to generate a reaction force, so that the pile body of the steel pipe pile 1 returns to the positive direction, and the purpose of correcting the deviation is achieved. The plumb gauge, the strain sensor, the acceleration sensor and the like are responsible for monitoring the verticality, the speed, the depth and the like in the pile sinking process during pile sinking, and the vertical deviation correcting device is controlled according to the reflected pile sinking condition.

The embodiment also provides a construction method of the offshore wind power combined single-pile foundation, which specifically comprises the following steps:

(1) prefabricating components such as the steel pipe pile 1, the variable-section T-shaped wing plate 2 and the like on land; the manufactured member should detect the quality and the matching degree in advance, the sealing performance and the reliability are checked after the combined single-pile foundation is combined, and the member can be delivered out of a warehouse after reaching the standard.

(2) Carrying the component offshore to a design pile location; during carrying, the steel pipe pile 1 and the variable cross-section T-shaped wing plate 2 can be respectively borne on a plurality of ships, so that the transportation is facilitated. And (5) after the design pile position is reached, the pile position condition is actually surveyed, and the pile sinking can be prepared after the design comparison conforms to the standard.

(3) Combining the steel pipe pile 1 and the variable cross-section T-shaped wing plate 2 into a whole through a mortise and tenon structure 5 and assisted by high-strength bolts; before sinking the pile, the components are assembled and the operation of the instruments is checked.

(4) Hoisting and sinking the combined single pile foundation to a designed pile position, sinking the pile after pile stabilization, controlling the verticality in the pile sinking process, and ensuring the verticality to reach the standard through the auxiliary pile sinking vertical deviation rectifying mechanical structure; and (3) stabilizing the pile during hoisting of the single pile, avoiding the pile body from shaking, aligning the pile position, ensuring the verticality of the single pile, and performing pile sinking after determining that the early preparation link is correct.

(5) After sinking the pile to the designed elevation, checking the bearing capacity of the single-pile foundation and reinforcing the foundation. After the pile is sunk to the designed elevation, the sinking condition of the variable cross-section T-shaped wing plate 2 is checked, and if a large gap exists between the flange 22 and the steel pipe pile 1 after sinking, stacking objects are preferably filled in the gap to reinforce the single-pile foundation.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. The offshore wind-power combined single pile foundation is characterized by comprising a steel pipe pile and a plurality of variable cross-section T-shaped wing plates, wherein mortise slots matched with the variable cross-section T-shaped wing plates in quantity are vertically formed in the outer surface of the steel pipe pile, and tenons matched with the mortise slots are arranged on the variable cross-section T-shaped wing plates, so that the variable cross-section T-shaped wing plates and the steel pipe pile are fixedly connected through a mortise and tenon structure formed by the mortise slots and the tenons;

the variable cross-section T-shaped wing plate consists of a web plate and a flange which are mutually and vertically connected, wherein the web plate is provided with the tenon, and the length of the web plate is gradually reduced from top to bottom;

a groove which is communicated up and down is processed inwards at one end of the web plate, which is far away from the steel pipe pile, a bulge which can be inserted into the groove in a matched manner is vertically arranged in the middle position of the flange, the groove is rotatably connected with the bottom of the bulge, a driving telescopic piece is further arranged in the groove, and two ends of the driving telescopic piece are respectively hinged with the bottom of the groove and the bulge;

the active telescopic piece is matched with a plumb instrument, a strain sensor and an acceleration sensor which are additionally arranged to form a mechanical structure for assisting vertical deviation correction of the pile sinking, when the deviation of the corresponding steel pipe pile body excessively deviates to one side to be corrected, the active telescopic piece in the variable cross section T-shaped wing plate corresponding to the side is opened, and the flange of the variable cross section T-shaped wing plate is in contact with the foundation to generate reaction force, so that the steel pipe pile body returns to the positive direction in the opposite direction, and the purpose of correcting the deviation is achieved.

2. The offshore wind-power combined single-pile foundation according to claim 1, wherein a pile tip is further connected to the bottom of the steel pipe pile, and the pile tip and the bottom end of the steel pipe pile are welded and sealed.

3. The offshore wind-power combined single pile foundation of claim 2, wherein the pile toe is open, cross, quadrangular pyramid, hexagonal pyramid or conical.

4. The offshore wind-power combined single pile foundation according to claim 1, wherein a stiffening rib is further arranged inside the steel pipe pile.

5. The offshore wind-power combined mono-pile foundation of claim 1, wherein the web has a thickness of 0.2-0.5m and a height of 0.2-2 m;

the thickness of the flange is 0.2-0.5m, and the width is 0.5-1 m.

6. The offshore wind-power combination monopile foundation of claim 1, wherein the active telescopic member is a jack;

the groove is rotatably connected with the bottom of the bulge through a large-diameter bolt.

7. The offshore wind-power combined single-pile foundation according to claim 1, wherein the mortise and tenon structure is further reinforced by high-strength bolts.

8. A construction method of an offshore wind power combined single pile foundation according to any one of claims 1 to 7, comprising the steps of: