CN105201010B - Offshore wind turbine assembled taper pile basis - Google Patents

Abstract

The invention discloses an assembled inclined pile foundation for an offshore fan. Including the wind turbine tower, the steel pile foundation and the transition steel structure connected between the steel pile foundation and the wind turbine tower. The steel structure is connected to each other; the steel structure is transformed into a tree branch structure including a central tube and multiple welded branches around the central tube. The bottom of each branch is coaxially connected to the top of the steel pile foundation through a flange, and the top of the central tube is The blue plate is coaxially connected with the bottom end of the fan tower. The invention has strong bearing capacity, high reliability, good fatigue resistance, no on-site welding and grouting, and relatively low requirements on engineering equipment and construction technology.

Description

Assembled inclined pile foundation for offshore wind turbines

technical field

The invention relates to a pile foundation structure, in particular to an assembled inclined pile foundation for offshore wind turbines, which is suitable for wind turbines with large installed capacity and deep sea areas.

Background technique

Wind energy is currently one of the fastest growing renewable energy sources with the best industrial prospects. Due to the high wind speed, long-lasting and stable wind force and high wind energy output at sea, the small wind turbulence has little loss of life of wind turbines, and the construction and use of wind turbines are less restricted by land and environmental noise. Wind turbines have moved from land to sea and large-scale become the trend of international wind power development.

At present, offshore wind turbines generally use large-diameter single pile foundations, tripod foundations and tetrapod foundations, jacket foundations, high pile cap foundations and other foundation forms. However, in the actual application process, due to various problems in their respective structures, their promotion and application are more or less restricted.

Large-diameter single-pile foundation: Although its foundation structure is simple in force and easy to manufacture, its large pile diameter requires high construction equipment (a large hydraulic piling hammer is required), and it is difficult to sink piles in special geological conditions; Conditions and water depth constraints are relatively large, and water that is too deep is prone to large bending deformation; it is very sensitive to erosion, and anti-scouring measures need to be carefully designed; the calculation theory of pile horizontal deformation under long-term cyclic loading is not perfect.

Tripod foundation and tetrapod foundation: They have the advantages of high overall structural rigidity and a wide range of applicable water depths. However, in the actual construction process, the grouting connection construction between the pile and the tripod or tetrapod is very difficult, which seriously hinders their popularization and application; their foundation size is large, and the pre-processing site is large; there are many rods. Lifting and welding are required; there are many structural nodes, and the workload of welding seam processing is large; the stress concentration of welding nodes is obvious, and there is a risk of node fatigue damage; foundation leveling is difficult, and generally each pile needs to be equipped with a special underwater leveling device and clamps. Pile device.

Jacket foundation: due to its advantages of high overall structural rigidity, small environmental loads such as wave currents, and suitability for sea areas with large water depths, it has received more and more attention in recent years. However, like the tripod foundation or the tetrapod foundation, the grouting connection between the pile and the jacket also troubles the design and construction personnel; at the same time, its large foundation size requires a large pre-processing site; there are many rods, which require hoisting and welding ; It is necessary to set up a more complex transition connection structure; the force transmission is more complicated; the node fatigue problem is prominent; the foundation leveling is difficult.

High pile cap foundation: Relatively speaking, the construction equipment and experience of this foundation form are mature, and the connection between the foundation and the wind turbine tower is similar to that of onshore wind turbines. However, its cap platform construction requires various measures such as steel casing, steel cage hoisting, and concrete mixing, and the maintenance time is long; when large-volume concrete is poured, large-area temperature cracks and shrinkage cracks are easily generated on the cap surface, affecting the cap. Structural durability; large-volume concrete structure with high cantilever, unfavorable for earthquake resistance; high cost and long construction period.

Based on the above analysis, there is a lack of a new form of pile foundation that is safe, reliable, convenient to construct, and economically reasonable to promote the rapid development of offshore wind power.

Contents of the invention

The technical problem to be solved by the present invention is to provide an assembled inclined pile foundation for offshore wind turbines, which is a new type of steel structure foundation suitable for offshore wind turbine foundations composed of wind turbine towers, steel pile foundations and converted steel structures.

The invention solves the problems existing in the above-mentioned existing gravity foundations, single pile foundations, tripod foundations or tetrapod foundations, jacket foundations and high pile cap foundations and other foundation forms.

Technical solution of the present invention is as follows:

The invention comprises a wind turbine tower, a steel pile foundation and a transition steel structure connected between the steel pile foundation and the wind turbine tower, the steel pile foundation is installed obliquely toward the wind turbine tower, and the wind turbine tower and the steel pile foundation are respectively connected to each other through a flange plate. Convert steel connections.

The conversion steel structure is a branch-shaped structure including a central cylinder and multiple welded branches around the central cylinder. The bottom of each branch is coaxially connected to the top of the steel pile foundation through a flange, and the top of the central cylinder is It is coaxially connected with the bottom end of the fan tower.

The branches of the transfer steel structure are obliquely welded to the side wall of the central cylinder.

The conversion steel structure has three branches, and the three branches form 120 degrees with each other.

The conversion steel structure has four branches, and the four branches form 90 degrees with each other.

The steel pile foundation is an inclined pile, and the slope ranges from 1/5 to 1/7.

The transition steel structure is a lattice transition steel structure, which is arranged above the splash zone.

The steel pile foundation is a round steel pipe pile.

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

1) Compared with the existing gravity foundation and single pile foundation, it is more suitable for wind turbines with deeper water depth and larger installed capacity in wind farm sites, and has better stability and reliability;

2) Compared with the existing tripod foundation, high pile cap foundation and jacket foundation, the foundation form proposed by the present invention is more concise and clear, and has obvious advantages in terms of stability and fatigue resistance, and because of its Most of the components are factory prefabricated components, which do not require on-site grouting, which reduces the risk and difficulty of on-site construction and shortens the construction period.

The conversion steel structure and inclined pile foundation designed by the present invention can skillfully convert the bending moment of the top surface of the foundation caused by the horizontal load on the upper structure into the axial force of the inclined pile, so that the overall force of the fan more scientific.

Description of drawings

Fig. 1 is the front view of the present invention when adopting three pile foundations.

Fig. 2 is the plan view of the present invention when adopting three pile foundations.

Fig. 3 is the plan view of the present invention when adopting four pile foundations.

In the figure: 1. Fan tower, 2. Steel pile foundation, 3. Transformation steel structure, 4. Flange, 5. Elevation of splash zone.

detailed description

Below in conjunction with accompanying drawing and embodiment the present invention will be described in further detail:

As shown in Fig. 1, Fig. 2 and Fig. 3, the present invention includes a fan tower 1, a steel pile foundation 2 and a conversion steel structure 3 connected between the steel pile foundation 2 and the fan tower 1, and the steel pile foundation 2 is directed toward the wind turbine The tower tube 1 is installed obliquely, and the fan tower tube 1 and the steel pile foundation 2 are respectively connected with the transfer steel structure 3 through the flange plate 4 .

As shown in Fig. 1, Fig. 2 and Fig. 3, the conversion steel structure 3 is a branch-shaped structure including a central tube and multiple branches around the central tube. 2 are connected coaxially at the top, and the top of the central tube is coaxially connected with the bottom end of the fan tower 1 through the flange 4.

As shown in Figure 1, when the number of piles is three or four, the side wall of the central cylinder of the converted steel structure is welded correspondingly to the leg columns that will be connected with the steel piles at the bottom in the future. This kind of structure can effectively improve the anti-fatigue ability of the converted steel structure, and make the structural stress mode more scientific.

The top of the branch of the conversion steel structure 3 is welded obliquely to the side wall of the central cylinder, so that the bottom inclined pile can be buried in the soil with an inclination of 1/6-1/7.

The conversion steel structure 3 can have three branches or four branches. When the foundation form of three piles is adopted, as shown in FIG. 120 degrees; when the foundation form of four piles is adopted, as shown in Figure 3, the four branches connected to the central cylinder of the conversion steel structure 3 and the steel pile foundation 2 form an angle of 90 degrees.

The steel pile foundation 2 is an inclined pile, and the range of its inclination is 1/5-1/7. The preferred steel pile foundation 2 can be a round steel pipe pile.

The transfer steel structure 3 is a lattice-type transfer steel structure, which is set above the splash zone. As shown in FIG. 1 , the bottom of the transfer steel structure 3 is higher than the elevation 5 of the splash zone.

Concrete construction process of the present invention is as follows:

1) Use piling equipment to drive the steel pile foundation 2 into the specified depth at the specified position, and ensure that the inclination of the steel pile foundation 2 is between 1/5 and 1/7 after the construction is completed;

2) Design the conversion steel structure 3 according to the actual horizontal position and elevation of each pile top flange 4 on site to ensure that the conversion steel structure 3 can be well connected with each steel pile foundation 2 and the fan tower 1. The converted steel structure is prefabricated in the factory and delivered to the site;

3) Install the conversion steel structure 3, and fix the conversion steel structure 3, the fan tower 1 and the steel pile foundation 2 through the flange 4. This connection method is a purely mechanical connection, which eliminates the cumbersome construction procedures of on-site grouting, greatly saves construction costs and shortens the construction period;

4) Hoist the fan tower 4, and install shipbuilding components, cable pipes and other auxiliary facilities on the conversion steel structure and piles.

Compared with the existing pile foundation, the present invention cleverly converts the bending moment caused by the horizontal load on the superstructure into the axial force of the inclined pile to the maximum, and is more suitable for wind farm sites with deeper water depth and larger installed capacity. The wind turbine has better stability and reliability, and does not require on-site grouting, which reduces the risk and difficulty of on-site construction, shortens the construction period, and has remarkable technical effects.

Claims (6)

1. A construction method for an assembled inclined pile foundation for offshore wind turbines, characterized in that: An assembled inclined pile foundation for offshore wind turbines is adopted, and the assembled inclined pile foundation for offshore wind turbines includes a wind turbine tower (1), a steel pile foundation (2) and connections between the steel pile foundation (2) and the wind turbine tower (1) The conversion steel structure (3), the steel pile foundation (2) is installed obliquely towards the fan tower (1), and the fan tower (1) and the steel pile foundation (2) are connected to the conversion steel structure ( 3) connected; 1) Use piling equipment to drive the steel pile foundation (2) into the specified depth at the specified position, and ensure that the inclination of the steel pile foundation (2) is between 1/5 and 1/7 after the construction is completed; 2) Design the conversion steel structure (3) according to the actual horizontal position and elevation of each pile top flange (4) on site to ensure that the conversion steel structure (3) is compatible with each steel pile foundation (2) and fan tower (1) They can be well connected and transported to the site after the conversion steel structure (3) is prefabricated in the factory; 3) Install the conversion steel structure (3), and fix the conversion steel structure (3) with the fan tower (1) and the steel pile foundation (2) through the flange (4). The cumbersome construction process of on-site grouting is eliminated, which greatly saves construction costs and shortens the construction period; 4) Hoist the fan tower (1), and install auxiliary facilities such as berthing components and cable pipes on the converted steel structure and piles. 2. The construction method of an assembled inclined pile foundation for offshore wind turbines according to claim 1, characterized in that: the conversion steel structure (3) is a tree that includes a central cylinder and a plurality of welded branches around the central cylinder Fork-shaped structure, the bottom of each branch is coaxially connected with the top of the steel pile foundation (2) through the flange (4), and the top of the central tube is coaxial with the bottom of the fan tower (1) through the flange (4) connect. 3. The construction method of an assembled inclined pile foundation for offshore wind turbines according to claim 2, characterized in that: the branches of the transition steel structure (3) are obliquely welded to the side wall of the central cylinder. 4. The construction method of an assembled inclined pile foundation for offshore wind turbines according to claim 2, characterized in that: the transition steel structure (3) has three branches, and the three branches form 120 degrees with each other. 5. The construction method of an assembled inclined pile foundation for offshore wind turbines according to claim 2, characterized in that: the transition steel structure (3) has four branches, and the four branches form 90 degrees with each other. 6 . The construction method of an assembled inclined pile foundation for offshore wind turbines according to claim 1 , characterized in that: the transition steel structure ( 3 ) is a lattice transition steel structure, which is arranged above the splash zone. 7 .