WO2022127466A1

WO2022127466A1 - Novel offshore wind turbine foundation suitable for shallow covering layer and construction method therefor

Info

Publication number: WO2022127466A1
Application number: PCT/CN2021/130649
Authority: WO
Inventors: 罗仑博; 张炜; 闫俊义; 徐海滨; 牛玉龙; 代加林; 王卫; 张泽超; 于光明
Original assignee: 中国长江三峡集团有限公司
Priority date: 2020-12-17
Filing date: 2021-11-15
Publication date: 2022-06-23
Also published as: CA3177328A1; CA3177328C; DE112021000948T5

Abstract

A novel offshore wind turbine foundation suitable for a shallow covering layer and a construction method therefor, the offshore wind turbine foundation comprising a single pile (1). A gravity disc (3) is fixedly mounted on the single pile (1); a plurality of helical piles (2) are evenly distributed on the periphery of the gravity disc (3); and adjacent helical piles (2) are fixedly connected to each other to form an integral structure. The uplift-resisting bearing capacity and horizontal bearing capacity of the foundation are improved by means of the helical piles (2) and the gravity disc (3); the horizontal displacement of the pile body is reduced; the bending moment of the pile body is reduced; and the combination and rigid connection of the helical piles (2), the gravity disc (3), and the single pile (1) improve various mechanical properties of the whole foundation, such that the construction requirement for safe and stable operation of an offshore wind turbine can be met without needing to inserting the single pile (1) into the bedrock.

Description

A new type of offshore wind power foundation suitable for shallow cover and its construction method

technical field

The invention relates to the technical field of offshore wind power, in particular to a new offshore wind power foundation suitable for shallow covering layers and a construction method thereof.

Background technique

Offshore wind turbines bear the coupling effect of wind, waves, currents and other environmental loads in the whole life cycle, and the offshore wind power foundation is required to have good composite bearing performance, including horizontal bearing capacity, bending moment bearing capacity, vertical bearing capacity and uplift Carrying capacity. At present, the cost of offshore wind power infrastructure construction accounts for about 30% of the total cost of offshore wind farm construction in deep waters. With the change of the national new energy subsidy policy, the subsidy for the on-grid tariff of offshore wind power will be cancelled by the end of 2021. Therefore, cost reduction and efficiency increase have become the top priority of the development of the offshore wind power industry, and a new basic type of offshore wind power needs to be developed urgently.

The geological conditions of various sea areas in my country are quite different. For example, the overburden in the sea areas of Guangdong and Fujian is relatively shallow. In order to meet the ever-increasing capacity of wind turbine units, the bearing capacity of offshore wind power foundations is also required to increase, resulting in a corresponding increase in the pile diameter of the foundation, and even rock-socketed construction. At present, the single-pile foundation accounts for more than 80% of the offshore wind power construction, which is regarded as the most mature foundation type and has the advantages of simple production and short construction period. However, large-scale drilling equipment needs to be drilled in the single-pile rock-socketed construction. Compared with the piling construction in the overburden, the technical process is more complicated, the technical difficulty is greater, the risk of hole collapse is high, the construction progress control is difficult, and the construction More expensive. At the same time, the shallow overburden rock-socketed pile needs to be deeply embedded in order to improve the enough resistance to horizontal load, and the fixed end of the single pile is deeper, the bending moment of the single pile is larger, and the required strength of the single pile is higher. higher. In addition, for shallow overburden sea areas, gravity-based shallow foundations are widely used, which have the characteristics of good economy and wide application range, and have excellent vertical ultimate bearing capacity, which is a foundation form with good application prospects. . However, compared with its vertical bearing performance, its anti-overturning, anti-slipping, especially anti-pulling performance is weak, and there is a certain degree of engineering risk in applying it to offshore wind power foundations.

Based on the shortcomings of the existing offshore wind power foundation, it is urgent to propose a new type of offshore wind turbine foundation, which can be applied to shallow overburden layers. Through the new foundation, the single pile does not need to be deeply embedded in the bedrock, and on the basis of satisfying the vertical bearing capacity , which can better meet the horizontal and bending moment bearing capacity, reduce the difficulty and cost of construction, improve the construction speed, and at the same time provide a certain anti-scour ability, and ensure the safe and stable operation of the fan.

SUMMARY OF THE INVENTION

The invention aims to solve the problem of insufficient types of offshore wind power foundations in the current shallow covering layer, solve the difficult problems of high construction difficulty, high cost, long construction period, etc., such as rock-socketed construction of a single pile foundation, and provides an offshore wind power suitable for shallow covering layers. A new foundation for wind power and its construction method, the present invention mainly increases the stiffness of the soil around the pile by increasing the gravity disk, improves the anti-overturning ability and the anti-scour ability of the foundation, and improves the anti-pulling bearing capacity and level of the foundation through the screw pile and the gravity disk. Bearing capacity, reduce the horizontal displacement of the pile body, and reduce the bending moment of the pile body; by splicing and rigidly connecting the screw pile, the gravity plate and the single pile, the mechanical indexes of the entire foundation are improved; thus, the single pile does not need to be embedded in the bedrock. to meet the engineering needs of the safe and stable operation of offshore wind power.

In order to realize the above-mentioned technical features, the purpose of the present invention is achieved as follows: a new type of offshore wind power foundation suitable for shallow covering layer, which includes a single pile, on which a gravity disk is fixedly installed, and the gravity disk is A plurality of screw piles are uniformly distributed and fixedly installed on the periphery; the adjacent screw piles are fixedly connected to form an integral structure.

The single pile adopts a large-diameter steel pipe pile; a collar for fixing the gravity disk is arranged on the single pile, and a rigid connection is formed between the two.

The gravity disk includes a gravity disk foundation, and a center ring is arranged at the center of the gravity disk base; the single pile passes through the center ring, and the two form a contact fit; the gravity disk foundation is centered on the center ring A plurality of connecting rods are evenly distributed and fixed, the other end of the connecting rods is fixed with a screw pile mounting seat for installing the screw pile, and a plurality of pins are evenly distributed on the inner side wall of the screw pile mounting seat.

The gravity disk foundation adopts a concrete structure or a filler structure; the concrete structure adopts an integral prefabricated structure on the shore; the filler structure adopts a cemented rockfill body, and the cemented rockfill body is filled with loose-grained rockfill, And through the underwater grouting technology, the cemented rockfill body and the structured cemented rockfill body with high water permeability are formed.

The spiral pile includes a steel pipe pile, and a spiral pile blade is arranged on the outer wall of the steel pipe pile and along its length direction, the bottom end of the steel pipe pile is provided with a spiral pile head, and the top end of the steel pipe pile is provided with a force for and gravity. The bolt of the plate is matched with the bolt hole of the screw pile.

The top of the screw pile is provided with a screw pile installation and connection part for quick disassembly and connection with the pile body sinking construction equipment. The screw pile installation and connection part includes a screw pile installation key fixed on the top of the steel pipe pile. The screw pile installation keyway at the bottom end of the transmission rod of the submerged construction equipment is matched and connected, and the torque is transmitted.

The helical pile blades are in annular arc shape, and the inclination angle, quantity, interval and diameter of the blades can be selected and used according to the geological conditions and the load of the fan unit.

The structure type of the gravity disk and the array arrangement of the screw piles can be triangular, square, hexagonal or circular; the number and array arrangement of the screw piles can be selected and adjusted according to the geological conditions and the load of the fan unit. use.

The cross section of the gravity disc foundation adopts a rectangle or a trapezoid.

The construction method of the new foundation for offshore wind power with shallow cover, including the following steps:

Step 1: Use the offshore jack-up platform or the offshore wind power construction ship to sink all the screw piles to the design pile position one by one, connect the screw piles to the top of the screw piles through the construction ship connecting rod and screw pile installation connecting parts, and screw the screw piles into In the covering layer, after reaching the design depth, reversely twist the connecting rod to realize the separation of the screw pile installation and connecting parts;

Step 2: Lift and sink the gravity disk, make all the screw pile mounts pass through all the screw piles, and use the gravity disk's own weight or external pressure to make the bolts in the screw pile mounts and the screw piles bolt. The holes are butted; then, the hydraulic concrete is poured into the screw pile mounting seat through the underwater grouting equipment to realize the rigid connection between the screw pile and the gravity disk;

Step 3: The single pile is hoisted and sunk through the central ring, partially penetrated below the mud surface by its own weight or external pressure, and then the single pile is driven to the design depth by the pile driving equipment, that is, the single pile When the collar is in contact with the center ring of the gravity disk, the hydraulic concrete is poured into the center ring through the underwater grouting equipment.

The present invention has the following beneficial effects:

1. The present invention proposes a new type of offshore wind power foundation suitable for shallow covering layer and its construction method. This structural form combines single piles, screw piles and gravity disks, and makes full use of the advantages of each component to form a new composite type. It is suitable for the sea area with shallow covering layer, which can avoid the problem of rock-socketed construction of single-pile foundation.

2. The gravity plate increases the stiffness of the soil around the pile, and improves the anti-overturning ability and anti-scour ability of the foundation. The screw pile and the gravity plate improve the anti-pulling bearing capacity and horizontal bearing capacity of the foundation, and reduce the horizontal displacement of the pile body. The bending moment of the pile body is reduced, thereby improving the composite bearing capacity of the foundation under long-term cyclic loading and extreme working conditions.

3. In addition, the installation and construction of screw piles are flexible, safe and economical. The underwater grouting construction technology is relatively mature, which can connect single piles, screw piles and gravity disks.

4. A variety of materials can be used for the final rockfill, and the rockfill can be connected into a rigid or flexible structure that is permeable or impermeable through materials such as gel.

Description of drawings

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

FIG. 1 is a front view of a new type of foundation for offshore wind power according to the present invention, which is suitable for shallow cover.

FIG. 2 is a top view of the new foundation for offshore wind power in FIG. 1 .

FIG. 3 is a front view of a single pile of the new foundation for offshore wind power in FIG. 1 .

FIG. 4 is a top view of a single pile of the new foundation for offshore wind power in FIG. 3 .

FIG. 5 is a front view of a gravity plate of the new foundation for offshore wind power in FIG. 1 .

FIG. 6 is a top view of the screw pile mounting seat of the gravity disk in FIG. 5 .

FIG. 7 is a front view of a screw pile of the new foundation for offshore wind power in FIG. 1 .

FIG. 8 is a schematic view of the installation of the screw pile in FIG. 7 .

FIG. 9 is a schematic diagram of the screw pile installation and connection components in FIG. 8 .

10 to 11 are cross-sectional views of modified examples of the screw pile according to the embodiment of the present invention.

12 is a cross-sectional view of a modified example of the gravity plate according to the embodiment of the present invention.

13 to 15 are top views of modified examples of the gravity plate according to the embodiment of the present invention.

In the figure: single pile 1, screw pile 2, gravity disk 3; collar 1-1; steel pipe pile 2-1, screw pile blade 2-2, screw pile head 2-3, screw pile bolt hole 2-4 , screw pile installation and connection parts 2-5; screw pile installation key 2-5-1, screw pile installation keyway 2-5-2; central ring 3-1, connecting rod 3-2, screw pile installation seat 3-3 , Gravity plate base 3-4, latch 3-5.

Detailed ways

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

Example 1:

Referring to Figures 1-15, a new type of offshore wind power foundation suitable for shallow covering layers includes a single pile 1, on which a gravity plate 3 is fixedly installed, and the periphery of the gravity plate 3 is uniformly distributed and fixedly installed A plurality of screw piles 2; the adjacent screw piles 2 are fixedly connected to form an integral structure. By adopting the foundation of the above structure, the mechanical indexes of the whole foundation are improved by splicing and rigidly connecting the screw pile, the gravity plate and the single pile. In this way, the engineering needs of the safe and stable operation of offshore wind power can be met without the need for the single pile to be embedded in the bedrock.

Further, the single pile 1 adopts a large-diameter steel pipe pile; a collar 1-1 for fixing the gravity disk 3 is arranged on the single pile 1, and a rigid connection is formed between the two. The above-mentioned collar 1-1 ensures that the monopile 1 can be reliably connected to the gravity plate 3 .

Further, the gravity plate 3 includes a gravity plate foundation 3-4, and a center ring 3-1 is arranged at the center of the gravity plate base 3-4; the single pile 1 passes through the center ring 3-1, and the two A plurality of connecting rods 3-2 are evenly distributed and fixed on the gravity disk base 3-4 with the center ring 3-1 as the center, and the other end of the connecting rod 3-2 is fixed with a screw for installing The screw pile mounting seat 3-3 of the pile 2, the inner side wall of the screw pile mounting seat 3-3 is provided with a plurality of pins 3-5 evenly distributed. The anti-overturning ability of the single pile 1 is effectively enhanced by the above-mentioned gravity disk 3, and its bearing capacity is enhanced.

Further, the gravity disk foundation 3-4 adopts a concrete structure or a filler structure; the concrete structure adopts the form of an integral prefabricated structure on the shore; the filler structure adopts a cemented rockfill body, and the cemented rockfill body is a filling structure. Build bulk rockfill, and form cemented rockfill and structured cemented rockfill with high water permeability through underwater grouting technology. By adopting the above-mentioned various structural forms, its adaptability is enhanced.

Further, the screw pile 2 includes a steel pipe pile 2-1, a screw pile blade 2-2 is arranged on the outer wall of the steel pipe pile 2-1 and along its length direction, and the bottom end of the steel pipe pile 2-1 is arranged There is a screw pile head 2-3, and the top end of the steel pipe pile 2-1 is provided with a screw pile bolt hole 2-4 for matching with the bolt 3-5 of the gravity plate 3. The above-mentioned screw piles 2 are drilled below the covering layer, thereby improving the bearing capacity of the gravity disk 3 .

Further, the top of the screw pile 2 is provided with a screw pile installation and connection part 2-5 for quick disassembly and connection with the pile body sinking construction equipment. The screw pile installation and connection part 2-5 includes a steel pipe pile 2-1 The screw pile installation key 2-5-1 at the top and the screw pile installation key 2-5-1 are connected with the screw pile installation keyway 2-5-2 at the bottom end of the transmission rod of the pile sinking construction equipment, and transmit torque. The above-mentioned screw pile installation and connection components 2-5 ensure that the screw pile 2 can be quickly connected with the construction equipment during the construction process, thereby transmitting torque.

Further, the spiral pile blades 2-2 are in the shape of an annular arc, and the inclination angle, number, interval and diameter of the blades can be selected and used according to the geological conditions and the load of the fan unit. The above structure ensures that it can be drilled smoothly.

Further, the structural type of the gravity disk 3 and the array arrangement of the screw piles 2 can be triangular, square, hexagonal or circular; the number and array arrangement of the screw piles 2 can be determined according to the geological conditions and the fan unit. Different loads can be selected and adjusted for use.

Further, the cross section of the gravity disk foundation 3-4 adopts a rectangular or trapezoidal shape.

Example 2:

Step 1: Use the offshore jack-up platform or the offshore wind power construction ship to sink all the screw piles 2 to the design pile position one by one, and connect the screw piles 2 to the top of the screw piles 2 through the construction ship connecting rod and the screw pile installation connection parts 2-5. Screw the screw pile 2 into the covering layer, and after reaching the design depth, reversely twist the connecting rod to realize the separation of the screw pile installation and connecting parts 2-5;

Step 2: Lift and sink the gravity plate 3, make all the screw pile mounts 3-3 pass through all the screw piles 2, and use the self-weight of the gravity plate 3 or the action of external pressure to make the screw pile mounts 3 The bolt 3-5 in -3 is docked with the bolt hole 2-4 of the screw pile; then, the hydraulic concrete is poured into the screw pile mounting seat 3-3 through the underwater grouting equipment to realize the rigid connection between the screw pile 2 and the gravity plate 3 ;

Step 3: Lift and sink the monopile 1 and pass through the central ring 3-1, partially penetrate below the mud surface by self-weight or external pressure, and then drive the monopile 1 into the design through the pile driving equipment. Depth, that is, when the single pile collar 1-1 is in contact with the center ring of the gravity disk, then pour hydraulic concrete into the center ring 3-1 through the underwater grouting equipment, and after the concrete has sufficient strength, make the single pile, The screw pile and the gravity disk form an integral load.

In the present invention, a plurality of screw piles with different lengths and different numbers of blades are formed into a composite body through connecting rods and a central single pile foundation, the central single pile is driven into the foundation, and the central single pile and the central cylinder are connected by grouting to form a whole; The connecting piece and the monopile foundation are anchored by grouting; finally, rockfill and gel medium are added to the connection groove to form a whole with the central monopile and the screw pile; through the implementation, it can not only adapt to larger water depths, but also avoid single piles. Due to the high cost of rock-socketed pile foundations, screw piles with different lengths and blades can increase the anti-overturning and pull-out bearing capacity. In addition, the gel stone moor in the connecting groove is both water permeable and anti-scour. At the same time, it also has the advantages of low investment cost and fast construction speed.

Claims

A new type of offshore wind power foundation suitable for shallow covering layer is characterized in that: it comprises a single pile (1), a gravity disk (3) is fixedly installed on the single pile (1), and the gravity disk (3) is A plurality of helical piles (2) are uniformly distributed and fixedly installed on the periphery; the adjacent helical piles (2) are fixedly connected to form an integral structure.
A new type of offshore wind power foundation suitable for shallow cover layer according to claim 1, characterized in that: the single pile (1) adopts a large-diameter steel pipe pile; The collar (1-1) of the disc (3), and makes a rigid connection between the two.
A new type of offshore wind power foundation suitable for shallow cover layer according to claim 1 or 2, characterized in that: the gravity plate (3) comprises a gravity plate foundation (3-4), and the gravity plate base (3) -4) A central ring (3-1) is arranged at the central part; the monopile (1) passes through the central ring (3-1), and the two form a contact fit; the gravity disk foundation (3-4) A plurality of connecting rods (3-2) are evenly distributed and fixed on the center ring (3-1), and the other end of the connecting rods (3-2) is fixed with a screw pile for installing the screw pile (2). A mounting seat (3-3), wherein a plurality of pins (3-5) are evenly distributed on the inner side wall of the screw pile mounting seat (3-3).
A new type of offshore wind power foundation suitable for shallow cover layer according to claim 3, characterized in that: the gravity disk foundation (3-4) adopts a concrete structure or a filler structure; Prefabricated structural form; the filler structure adopts cemented rockfill body, and the cemented rockfill body is filled with loose-grained rockfill material, and the cemented rockfill body and structured cemented pile with high water permeability are formed by underwater grouting technology stone body.
A new type of offshore wind power foundation suitable for shallow covering layer according to claim 1, characterized in that: the screw pile (2) comprises a steel pipe pile (2-1), and the steel pipe pile (2-1) The outer wall of the steel pipe pile (2-1) is provided with a screw pile blade (2-2) along its length direction, the bottom end of the steel pipe pile (2-1) is provided with a screw pile head (2-3), and the steel pipe pile (2-1) A screw pile bolt hole (2-4) for matching with the bolt (3-5) of the gravity plate (3) is provided at the top of the spool.
A new type of offshore wind power foundation suitable for shallow covering layer according to claim 1 or 5, characterized in that: the top of the screw pile (2) is provided with a screw for quick disassembly and connection with the pile sinking construction equipment The pile installation connection part (2-5), the screw pile installation connection part (2-5) includes the screw pile installation key (2-5-1) fixed on the top of the steel pipe pile (2-1), the screw pile installation key ( 2-5-1) It is connected with the screw pile installation keyway (2-5-2) at the bottom end of the transmission rod of the pile sinking construction equipment, and transmits the torque.
A new type of offshore wind power foundation suitable for shallow covering layers according to claim 5, characterized in that: the screw pile blades (2-2) are annular arcs, and the inclination angle, number, interval and diameter of the blades can be Select and use according to geological conditions and fan unit load.
A new type of offshore wind power foundation suitable for shallow covering layer according to claim 1, characterized in that: the structural type of the gravity disk (3) and the array arrangement of the screw piles (2) can be triangular, square, Hexagonal or circular; the number and array arrangement of the screw piles (2) can be selected and adjusted according to the different geological conditions and the load of the fan unit.
A new type of offshore wind power foundation suitable for shallow cover layer according to claim 3, characterized in that: the cross section of the gravity disk foundation (3-4) is rectangular or trapezoidal.
The construction method for a new type of offshore wind power foundation suitable for shallow covering layers according to any one of claims 1-9, characterized in that it comprises the following steps:

Step 1: Use the offshore jack-up platform or the offshore wind power construction ship to sink all the screw piles (2) to the design pile position one by one, and install the connecting parts (2-5) and the screw piles through the construction ship connecting rods and the screw piles (2) The top ends are connected, and the screw pile (2) is screwed into the covering layer, and after reaching the design depth, reversely twist the connecting rod to realize the separation of the screw pile installation connecting parts (2-5);

Step 2: hoist and sink the gravity plate (3), and make all the screw pile mounts (3-3) pass through all the screw piles (2), using the self-weight of the gravity plate (3) or an additional The pressure action makes the bolt (3-5) in the screw pile mounting seat (3-3) butt with the screw pile bolt hole (2-4); then, the hydraulic concrete is poured into the screw pile mounting seat ( 3-3), to realize the rigid connection between the screw pile (2) and the gravity plate (3);

Step 3: The single pile (1) is hoisted and sunk through the central ring (3-1), partially penetrated below the mud surface by self-weight or external pressure, and then the single pile ( 1) Drive to the design depth, that is, when the single pile collar (1-1) is in contact with the center ring of the gravity disk, then pour hydraulic concrete into the center ring (3-1) through the underwater grouting equipment, and wait for the concrete After sufficient strength is generated, monopile, helical pile and gravity disk are integrally loaded.