CN112127381A - Offshore wind power foundation and construction method of single-column variable-section negative pressure cylinder with sub-silo and single-column with dense beam at the top of the cylinder - Google Patents

Abstract

The invention relates to a bin-dividing single-column variable-section negative pressure cylinder offshore wind power foundation in a cylinder top dense beam cylinder, which comprises a single column and a negative pressure cylinder, wherein the top of the single column is connected with a fan bottom flange, and the single column is connected with the negative pressure cylinder through an inclined support; the upper end of the inclined support is fixedly connected with the wall of the single-column through the upper annular plate and the lower annular plate, and the lower end of the inclined support is fixedly connected with the top plate of the negative pressure cylinder to form a whole, so that the load borne by the single column is effectively transmitted to the negative pressure cylinder. The invention combines the advantages of simple construction of single pile foundation, definite force transfer, good stability of cylindrical foundation, convenient installation on the sea and the like, and solves the problems that the traditional pile type foundation needs large equipment for piling at the sea, and the rock-socketed construction has large difficulty, long construction period, high construction cost and the like. The invention is suitable for the water depth of 5-50 m, has simple structure and convenient manufacture, can avoid offshore piling and rock-socketing operation and can shorten the construction period; the steel consumption is less, the weight is light, the requirement on offshore construction equipment is relatively low, and the construction cost of foundation engineering can be reduced by more than 25%.

Description

Offshore wind power foundation and construction of single-column variable cross-section negative pressure cylinders method

technical field

The invention relates to an offshore wind power foundation structure, in particular to an offshore wind power foundation and a construction method for an offshore wind power base of a single-column variable-section negative pressure cylinder with a dense beam at the top of a cylinder.

Background technique

Due to the geological conditions such as silt, silt soil, clay, sand and so on in the offshore area of my country, in order to meet the requirements of foundation bearing capacity and foundation deformation, pile-type foundations such as single pile and jacket are usually used, which requires large hoisting ships and piling. Ship-assisted construction, through hammering, drive the bottom of the pile into a better bearing layer. This traditional pile foundation has high cost and long construction period. For example, in Fujian, Guangdong and other sea areas, it is mostly a rock foundation with a shallow cover. , If the pile foundation needs to be rock-socketed construction, it is difficult, the construction period is long, and the project cost is high.

With the increase of the single-unit capacity of offshore wind turbines, the use of traditional monopiles and jacket foundations needs to increase the size and material consumption of the foundations. Large-diameter monopiles and rock sockets are limited by large offshore construction equipment and become insurmountable problems. The risks are high, the construction period is long, and the project cost is high.

With the continuous advancement of technology, in order to solve the above problems, the industry has carried out continuous exploration. like:

The composite cylindrical foundation (patents CN107761755A, CN106759445) has been used in the negative pressure sinking installation method of offshore wind power and cylindrical foundations (patent CN105926661A), which can avoid offshore piling and rock-socketing operations, but the foundation is suitable for shallow water depth and weighs up to 5000 tons, the available construction equipment resources are few, and it is difficult to manufacture, transport and hoist.

An offshore wind power composite cylindrical foundation (patent CN207567801U) can avoid offshore piling and rock-socketing operations, but the stress concentration at the connection between the single column in the middle of the foundation and the steel pipe diagonal brace is very obvious, which is not conducive to the fatigue and punching of the foundation, and consumes steel. Large quantity; reinforced concrete needs to be installed on the top plate of the cylinder, and concrete needs to be poured into the interior of the diagonal bracing. The construction process is many and complicated, and the weight of the foundation is large, which is not conducive to the production, transportation and hoisting of the foundation; the project cost is high.

The offshore fan monopile-suction cylinder combined foundation and its construction method (patent CN110016930A) can avoid offshore piling and rock-socketing operations. The foundation is composed of upper and lower cylinders, which is complicated in construction and difficult to coordinate in deformation. The connection is too weak, the roof of the tube has no effective support system, and the rigidity is weak, which cannot effectively transmit the fan load borne by the single pile in the middle to the tube.

A connection tool for single-column and composite cylinder combined foundation (CN 110607802 A) can avoid offshore piling and rock-socketing operations, only the upper ring plate is provided at the connection between the foundation diagonal brace and the middle single column, where stress is concentrated It will be obvious, unfavorable for fatigue, and large steel consumption; the diameter of the single column in the middle extends into the cylinder to form a middle compartment, because its diameter is smaller than that of the cylinder, it is easy to produce a soil plug effect during the negative pressure sinking process, which may cause the sinking failure; due to the small diameter of the single column in the middle, the length of other sub-silo boards in the cylinder is greatly increased, and buckling damage is likely to occur during transportation and sinking; the project cost is high.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention provides an offshore wind power foundation and a construction method for a single-column variable-section negative pressure cylinder with a single-column and a single-column in a dense beam at the top of the cylinder.

The technical scheme adopted in the present invention is: a single-column variable-section negative pressure cylinder offshore wind power foundation with a single-column variable cross-section at the top of a dense beam and a cylinder, comprising a single-column arranged vertically and a negative-pressure cylinder set at the bottom of the single-column. The top of the column is flanged to the bottom of the fan, and it is characterized in that: the single column is connected to the negative pressure cylinder through an oblique support; the upper end of the oblique support is fixedly connected to the single column column wall through the upper ring plate and the lower ring plate, and the lower end is connected to the negative pressure cylinder. The top plate of the pressure cylinder is fixedly connected to form a whole, which effectively transmits the load borne by the single column to the negative pressure cylinder.

Preferably, the inclined support includes a plurality of inclined columns uniformly arranged along the circumferential direction of the single column and a horizontal beam connected with the inclined columns. The lower part of the inclined column and the horizontal beam are connected by a straight section or arc transition; the horizontal beam penetrates radially through the negative pressure cylinder and is connected with the top plate of the negative pressure cylinder.

Further, each of the oblique columns is provided with longitudinal stiffeners along the length direction, one end of the longitudinal stiffeners is connected to the intersection of the upper ring plate and the single column, and the other end extends to the edge of the oblique column; the oblique column and the horizontal A transverse stiffener is provided at the intersection of the beams, and the transverse stiffener is perpendicular to the inclined column.

Further, horizontal supports are provided between two adjacent inclined columns to prevent out-of-plane instability and damage.

Further, the upper ring plate and the lower ring plate and the inclined column are connected by a straight section or a circular arc transition.

Preferably, a plurality of main beams are evenly arranged along the circumferential direction on the top plate of the negative pressure cylinder, each of the main beams is arranged radially along the top plate, and a plurality of secondary beams are arranged between the main beam and the inclined support, and many The secondary beams are all arranged in the circumferential direction of the roof.

Preferably, the negative pressure cylinder includes a top plate, an outer cylinder wall, an outer sub-silo plate and an inner sub-silo plate, and the outer and inner sub-silo plates, the top plate and the outer cylinder wall enclose a plurality of compartments.

Further, the top plate is provided with a drain and exhaust valve which is in one-to-one correspondence with the cabins.

Preferably, the single column has an equal diameter section or a circular section with a variable diameter section from top to bottom, and the bottom is connected to the top plate of the negative pressure cylinder through a T-ring beam.

The construction method of the above foundation includes the following steps:

a. The factory completes the basic prefabrication;

b. The foundation is transported to the designated installation site by barge or floating;

c. Lift the foundation off the barge by the floating crane (floating by discharging the water and gas in the negative pressure cylinder) and sink it to the seabed surface;

d. It sinks to a certain depth below the seabed by the dead weight of the foundation;

e. By discharging the water and gas in the negative pressure cylinder, a downward negative pressure is formed, and the foundation sinks the top surface of the cylinder to be in close contact with the seabed surface through negative pressure sinking. Negative pressure controls the installation slope of the foundation within a reasonable range.

The beneficial effects obtained by the present invention are:

1. The main body of the foundation is an all-steel structure, and the single column adopts a variable section with a large top and a small bottom. The diameter of the single column below the oblique support can be changed from 7m to 5m, which reduces the steel consumption by 210 tons and reduces the foundation buoyancy by 250t.

2. The horizontal beam at the bottom of the oblique support runs through the top of the cylinder, the top of the cylinder adopts a dense beam structure, and the main beam and the secondary beam are set to shorten the calculation span of the top plate of the cylinder. , to increase the fundamental frequency.

3. The single column does not extend into the cylinder, and the bottom is connected to the top plate through a T-ring beam. The middle part of the cylinder adopts a polygonal or circular cabin with a larger space, and the compartments in the cylinder are more uniform, and soil plugs will not be formed during the sinking process. , considering that the buoyancy of the foundation is reduced due to the variable cross-section of the single column, the total sinking resistance of the foundation is reduced from 100MN to 70MN, and the thickness of the outer wall of the cylinder can be reduced from 40mm to 25mm; at the same time, other components in the cylinder can be reduced. The calculated length of the warehouse plate enhances the ability to resist buckling and instability, and the thickness of the warehouse plate is reduced from 35mm to 20mm, reducing steel consumption.

4. Longitudinal stiffeners are added at the connection of the oblique support and single column, which can greatly reduce the stress concentration at the joint. The stress of the upper ring plate is reduced from 350MPa to 240MPa, and the thickness of the steel plate is reduced from 90mm to 60mm, which reduces the consumption of steel.

5. The lower ring plate is added at the connection between the oblique support and the single column, and the stiffness of the node increases, which can greatly reduce the stress concentration at the node, which is beneficial to the fatigue calculation. The fatigue hot spot stress generated by fans and waves is reduced from 35MPa to 20MPa. The thickness of the steel plate is reduced from 70mm to 55mm, reducing the consumption of steel.

Taking an offshore wind power project in the Guangdong sea area as the calculation background, the patented technology can save more than 30% of the steel consumption, and at the same time, it can reduce the lifting capacity of the offshore floating crane construction ship, and reduce the usage cost of construction equipment. The technology of the present invention can reduce the foundation engineering cost. More than 25% of the cost.

To sum up, the foundation of the present invention can be applied to a water depth of 5-50 meters, has a simple structure and is convenient to manufacture, can avoid offshore piling and rock-socketing operations, and can shorten the construction period; less steel consumption, light weight, and relatively high requirements for offshore construction equipment. Lower, which can reduce the cost of basic engineering by more than 25%.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is the elevation view of Fig. 1;

Fig. 3 is the top view of Fig. 1;

Fig. 4 is the structural schematic diagram of oblique support;

Fig. 5 is the elevation view of Fig. 4;

Fig. 6 is a schematic diagram of the distribution of the roof beam system of the negative pressure cylinder;

Fig. 7 is a schematic diagram of the structure of some warehouses in the negative pressure cylinder;

Figure 8 is a schematic structural diagram of an upper ring plate or a lower ring plate;

Reference signs: 1. Single column; 2. Oblique support; 3. Negative pressure cylinder (a, top plate; b, outer cylinder wall; c, outer sub-silo board; d, inner sub-silo board); 4. Upper ring plate ;5, lower ring plate; 6, arc plate transition; 7, longitudinal stiffener; 8, horizontal support; 9, T-ring beam; 10, secondary beam; 11, main beam; 12, drain and exhaust valve; 13 , inclined column; 14, horizontal beam; 15, horizontal beam intersecting transition connecting member; 16, arc transition; 17, transverse stiffener.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

As shown in Figures 1-8, a single-column variable-section negative pressure cylinder offshore wind power foundation of the present invention includes a single column 1 and a negative pressure cylinder 3. The single column 1 is vertically arranged, and the single column The top of the column 1 is flanged to the bottom of the fan, and the bottom is fixedly connected to the top plate a of the negative pressure cylinder 3 . The single column 1 is fixedly connected to the negative pressure cylinder 3 through the oblique support 2, the upper end of the oblique support 2 is fixedly connected to the column wall of the single column 1 through the upper ring plate 4 and the lower ring plate 5, and the lower end is fixedly connected to the top plate a of the negative pressure cylinder 3. As a whole, the load borne by the single column 1 is effectively transmitted to the negative pressure cylinder 3. The present invention utilizes the negative pressure system to discharge the water and gas in the negative pressure cylinder 3 to form a negative pressure, the foundation is sunk into the topsoil, and the top of the negative pressure cylinder 3 is in contact with the seabed surface. The soil layer can also be cleared of a certain depth of soft soil first, and then the foundation is installed. The invention combines the advantages of simple construction of a single pile foundation, clear force transmission, good stability of the cylindrical foundation, and convenient installation at sea. The foundation requires large-scale equipment for offshore piling operations and rock-socketed construction is difficult, long construction period and high cost.

In this embodiment, the single column 1 is a steel pipe, which is formed by rolling and welding steel pipes with a diameter of 5-20 m and a wall thickness of 30-200 mm. It is welded with the inclined support 2, and the bottom is welded with the top plate a of the negative pressure cylinder 3 through the T-ring beam 9.

2-5, in this embodiment, the inclined support 2 includes a plurality of inclined columns 13 and a horizontal beam 14 connected with the inclined columns 13, and the plurality of inclined columns 13 are evenly arranged along the circumferential direction of the single column 1 (in FIG. 4 ). , the single column 1 is evenly arranged with 6 inclined columns 13), the upper part of the multiple inclined columns 13 is fixedly connected with the single column 1 through the upper ring plate 4 and the lower ring plate 5, and the lower part of the multiple inclined columns 13 and the horizontal beam 14 are connected. The bottom end of the inclined column 13 can either be set at the edge of the top plate a of the negative pressure cylinder 3, or can be retracted and set within the diameter range of the top plate a of the negative pressure cylinder 3. The horizontal beam 14 runs through the negative pressure cylinder 3 radially, and is fixedly connected with the top plate a of the negative pressure cylinder 3. One end of the horizontal beam 14 is connected to the lower part of the inclined column 13 to form a similar "U"-shaped structure, and the other end is fixed in the middle. The horizontal beams intersect on the transition connecting members to form an integral inclined support 2 structure. In this embodiment, the inclined columns 13 are H-shaped steels with a height of 1.0-5 m; the horizontal beams 14 are H-shaped steels with a height of 0.3-2 m.

In this embodiment, each oblique column 13 is provided with a longitudinal stiffening rib 7 along the length direction. The longitudinal stiffener 7 is made of steel plate, with a width of 0.2 to 1.0m and a thickness of 20 to 150mm. The longitudinal stiffener 7 starts from the intersection of the upper ring plate 4, the single column 1 and the inclined column 13, and is welded to the inclined column along the inclined column 13. On the web, it extends to the end of the inclined column 13.

A transverse stiffening rib 17 is provided at the intersection of the inclined column 13 and the horizontal beam 14 , and the transverse stiffening rib 17 is perpendicular to the inclined column 13 . The transverse stiffening rib 17 is made of steel plate, with a width of 0.2-0.8 m and a thickness of 20-100 mm.

4 and 5 , in this embodiment, a horizontal support 8 is provided between two adjacent inclined columns 13 , and the horizontal support 8 connects all the inclined columns 13 to each other to prevent out-of-plane instability and damage. The horizontal support 8 is a steel pipe (a steel pipe with a diameter of 0.3 to 1.5 m is used in this embodiment), I-shaped, cross-shaped or box-shaped. When the out-of-plane stability calculation of the inclined column 13 meets the requirements, the horizontal support 18 can be cancelled.

8, in this embodiment, the upper ring plate 4 and the lower ring plate 5 and the inclined column 13 are connected 6 through a straight section or arc transition, and the upper ring plate 5 and the lower ring plate 5 are connected to the inclined column 13 along the circumferential direction. The top is welded, and both the upper ring plate 5 and the lower ring plate 5 are made of corrugated steel plates with a thickness of 20-150 mm.

3 and 6, a plurality of main beams 11 are evenly arranged along the circumferential direction on the top plate a of the negative pressure cylinder 3, and each main beam 11 is radially arranged along the top plate a. The main beam 11 and the horizontal beam of the oblique support 2 A plurality of secondary beams 10 are arranged between the 14, and the plurality of secondary beams 10 are arranged circumferentially along the top plate a. The main beam 11 is welded to the top plate a in the radial direction, one end is welded to the T-ring beam 9 at the bottom of the single column 1, the other end is welded to the outer cylinder wall b, and the secondary beam 10 is welded to the top plate a along the circumferential direction, with a spacing of 0.5 ~4.0m. The main beam 11 and the secondary beam 10 are T-shaped steels with a height of 0.3 to 2 m.

In conjunction with Fig. 7, in this embodiment, the negative pressure cylinder 3 includes a top plate a, an outer cylinder wall b, an outer sub-silo board c and an inner sub-silo board d, the outer sub-silo board c and the inner sub-silo board d and the top plate a and the outer sub-silo board d. The cylinder wall b encloses a plurality of cabins (5 to 11 cabins). The outer cylinder wall b is rolled and welded by steel pipe, the cylinder diameter is 10-50m, and the cylinder height is 5-30m; On the inside of the wall b, the inside of the negative pressure cylinder 3 is divided into 7 compartments; the top plate a is composed of a plurality of steel plates, welded on the outer sub-silo plate c, the inner sub-silo plate d and the top of the outer cylinder wall b to form the negative pressure cylinder 3, The top plate a is provided with a drainage and exhaust valve 12 that communicates with each cabin in a one-to-one correspondence.

The construction method of the above foundation includes the following steps:

a. The factory completes the basic prefabrication;

The basic prefab steps are as follows:

(1) A single column 1 is formed by coiling and welding the upper and lower steel pipes;

(2), the inclined column 13 is H-shaped steel, the horizontal beam 14 is T-shaped steel, the intersection of the horizontal beam 14 is connected by a solid casting or a thick-walled steel pipe 15, and the welding points are scattered, and the inclined column 13 and the horizontal beam 14 pass through the arc transition piece 16 connections to form an oblique support 2 system;

(3) The outer cylinder wall b is rolled and welded by steel pipes, the outer sub-silo plate c and the inner sub-silo plate d are composed of steel plates and welded on the inner side of the outer cylinder wall b, and the interior of the negative pressure cylinder 3 is divided into 7 compartments, The top plate a is composed of a plurality of steel plates, which are welded to the outer sub-silo plate c, the inner sub-silo plate d and the top of the outer cylinder wall b to form a negative pressure cylinder 3;

(4), the upper ring plate 4 and the lower ring plate 5 are welded to the top of the inclined column 13 along the circumferential direction;

(5), hoist the oblique support 2 system to the top of the negative pressure cylinder 3 and weld it to the top plate a;

(6), the bottom T-ring beam 9 is welded with the top plate a;

(7), the single column 1 passes through the reserved hole in the middle of the inclined support 2, the bottom is welded with the T-ring beam 9, and the middle is welded with the inclined column 13, the upper ring plate 4 and the lower ring plate 5;

(8) The longitudinal stiffener 7 starts from the intersection of the upper ring plate 4, the single column 1 and the inclined column 13, and is welded to the inclined column web along the inclined column 13, extending to the end of the inclined column 13;

(9) The transverse stiffeners 17 are symmetrically arranged along both sides of the inclined column web, and are welded with grooves on three sides of the inclined column;

(10) An exhaust and drain valve 12 is provided at the opening corresponding to the top plate a and each cabin;

b. The foundation is transported to the designated installation site by barge or floating;

c. Lift the foundation off the barge by the floating crane (floating by discharging the water and gas in the negative pressure cylinder) and sink it to the seabed surface;

d. It sinks to a certain depth below the seabed by the dead weight of the foundation;

e. By discharging the water and gas in the negative pressure cylinder, a downward negative pressure is formed, and the foundation sinks the top surface of the cylinder to be in close contact with the seabed surface through negative pressure sinking. Negative pressure controls the installation slope of the foundation within a reasonable range.

The basic principles and main structural features of the present invention have been shown and described above. The present invention is not limited by the above examples, and without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (7)

1. A single-column variable-section negative-pressure cylinder offshore wind power foundation with a single-column variable-section negative pressure cylinder in a dense beam at the top of the cylinder, comprising a single-column (1) arranged vertically and a negative-pressure cylinder (3) arranged at the bottom of the single-column (1), The top of the single column (1) is flanged to the bottom of the fan, and it is characterized in that: the single column (1) is connected to the negative pressure cylinder (3) through an oblique support (2); The upper ring plate (5) and the lower ring plate (6) are fixedly connected with the column wall of the single column (1), and the lower end is fixedly connected with the top plate (a) of the negative pressure cylinder (3) to form a whole, which bears the single column (1) The load is effectively transferred to the negative pressure cylinder (3); The inclined support (2) comprises a plurality of inclined columns (13) evenly arranged along the circumferential direction of the single column (1) and a horizontal beam (14) connected with the inclined columns (13), and the plurality of the inclined columns (13) The upper part is connected to the single column (1) through the upper ring plate (5) and the lower ring plate (6), and the lower part of the plurality of said inclined columns (13) and the horizontal beam (14) are intersected by straight sections or arc transitions connection; the horizontal beam (14) penetrates radially along the negative pressure cylinder (3), and is connected with the top plate (a) of the negative pressure cylinder (3); A plurality of main beams (11) are evenly arranged along the circumferential direction on the top plate (a) of the negative pressure cylinder (3), and each of the main beams (11) is radially arranged along the top plate (a). A plurality of secondary beams (10) are arranged between the beam (11) and the oblique support (2), and the plurality of secondary beams (10) are arranged circumferentially along the top plate (a); the negative pressure cylinder (3) includes Top plate (a), outer cylinder wall (b), outer sub-silo plate (c) and inner sub-silo plate (d), the outer sub-silo plate (c) and inner sub-silo plate (d) and top plate (a) and the outer cylinder wall (b) to form a plurality of compartments. 2. The single-column variable-section negative pressure cylinder offshore wind power foundation of claim 1, characterized in that: each of the oblique columns (13) is provided with longitudinal stiffeners along the length direction (7), one end of the longitudinal stiffening rib (7) is connected to the intersection of the upper ring plate (5) and the single column (1), and the other end extends to the edge of the inclined column (13); the inclined column (13) and the horizontal A transverse stiffening rib (17) is provided at the intersection of the beams (14), and the transverse stiffening rib (17) is perpendicular to the inclined column (13). 3. The offshore wind power foundation of the single-column variable-section negative pressure cylinder of sub-silo and single-column variable-section negative pressure cylinder in the top dense beam cylinder according to claim 1, is characterized in that: a horizontal support (8) is provided between two adjacent inclined columns (13). ) to prevent out-of-plane instability damage. 4. The single-column variable-section negative pressure cylinder offshore wind power foundation of claim 1, characterized in that: the upper ring plate (5) and the lower ring plate (6) and the inclined column (13) Connect by straight segment intersection or arc transition. 5. The offshore wind power foundation of the single-column variable-section negative pressure cylinder of sub-silo and single-column variable-section negative pressure cylinder in the top dense beam cylinder according to claim 1, is characterized in that: the top plate is provided with a drainage and exhaust valve (one-to-one correspondence with the cabin). 12). 6 . The single-column variable-section negative pressure cylinder offshore wind power foundation according to claim 1, characterized in that: the single-column (1) has an equal-diameter section or a variable cross-section from top to bottom. The circular section of the diameter section, the bottom is connected with the top plate (a) of the negative pressure cylinder (3) through the T-ring beam (9). 7. A construction method of a single-column variable-section negative pressure cylinder offshore wind power foundation in a single-column variable-section negative pressure cylinder in a dense beam at the top of the cylinder, characterized in that it comprises the following steps: a. The factory completes the basic prefabrication; b. Transport the foundation to the designated installation location; c. Set the foundation to the seabed; d. Set the depth by sinking to the seabed surface by the weight of the foundation; e. By discharging the water and gas in the negative pressure cylinder, a downward negative pressure is formed, and the foundation sinks the top surface of the cylinder to be in close contact with the seabed surface through negative pressure sinking. Negative pressure controls the installation slope of the foundation within a reasonable range.

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