CN114277834B - Wind power single pile foundation and construction method - Google Patents

Abstract

The invention discloses a wind power single pile foundation and a construction method, which comprises a single pile, wherein a prefabricated member group is arranged in the single pile, the prefabricated member group comprises a truss, a steel shaft, a pile casing and a baffle plate component, the truss and the baffle plate component are respectively fixed at the upper side and the lower side in the single pile, the steel shaft penetrates through the center of the truss and the baffle plate component to be fixed, the pile casing is sleeved at the upper section of the steel shaft, a jack is fixed at the lower end of the pile casing, a plurality of steel pipes are arranged between the steel shaft and the pile casing at intervals along the circumferential direction, the middle section of each steel pipe is connected with a top plate of the jack, the baffle plate component is used for enhancing the soil plug effect in the piling process, after piling is finished, the jack drives the steel pipe to move and drives the lower section of the steel pipe to slide along the chute of the baffle plate component and pass through the constructional hole to enter the soil body around the single pile, and the soil body around the pile is grouted and reinforced through the seamless steel pipe, so that the vertical, horizontal and anti-torsion bearing capacity of the single-pile foundation is comprehensively improved. The invention greatly improves the pulling resistance, overturning resistance and torsion resistance bearing capacity of the single pile for manufacturing the wind generating set.

Description

Wind power single-pile foundation and construction method

Technical Field

The invention relates to a wind power generation device and a construction method, in particular to a wind power single-pile foundation and a construction method.

Background

Currently, the clean and sustainable development of energy is a common concern in all countries of the world, and the gradual replacement of traditional fossil energy by clean green energy is a necessary trend. Therefore, offshore wind power construction has good resource potential and application prospect in China.

In the process of constructing an offshore wind farm, the wind power foundation is a key factor for ensuring reasonable budget and normal operation of a fan, whether in cost control or stability and reliability. According to statistics of BOEM company, in general offshore wind power project cost, a fan accounts for the largest proportion, and accounts for about 33% of the total cost; secondly, the wind power basis is 19 percent. Therefore, reasonable basic model selection and design are important links in saving cost and shortening construction period of offshore wind power. The wind power projects built and under construction are mostly concentrated in shallow sea areas, wherein a large-diameter single-pile foundation becomes the dominant foundation form.

The design idea of the large-diameter single-pile foundation of the offshore wind power at the present stage is very conservative, and the large-diameter single-pile foundation has the problems of high construction difficulty, complex environment and the like. On the basis of not increasing the construction difficulty and the construction period, the uplift resistance, the overturning resistance and the torsion resistance bearing capacity of a single pile for manufacturing the wind generating set are greatly improved, the pile length is shortened, the construction cost is obviously reduced, and the method is a difficult problem which is urgently needed to be solved in the industry at present.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a wind power single-pile foundation, which solves the problems that the existing single-pile foundation can not greatly improve the uplift resistance, the overturn resistance and the torsion resistance bearing capacity of a single pile for manufacturing a wind generating set on the basis of not increasing the construction difficulty and the construction period, shorten the pile length, enlarge the effective pile diameter and reinforce the soil mass around the pile.

The invention also aims to provide a construction method of the wind power single pile foundation.

The technical scheme is as follows: the wind power single pile foundation comprises a single pile, wherein a prefabricated component group is arranged in the single pile, the prefabricated member group comprises a truss, a steel shaft, a pile casing and a baffle plate component, the truss and the baffle plate component are respectively fixed on the upper side and the lower side in the single pile, the steel shaft penetrates through the truss and is fixed with the center of the baffle plate component, the protecting cylinder is sleeved on the upper section of the steel shaft, the lower end of the protecting cylinder is fixed with a jack, a plurality of steel pipes are arranged between the steel shaft and the protective cylinder at intervals along the circumferential direction, each steel pipe comprises an upper steel pipe section, a middle steel pipe section and a lower steel pipe section which are connected through flexible interfaces, the middle section of the steel pipe is connected with the top plate of the jack, the lower section of the steel pipe extends along the surface of the baffle plate component and can slide along the baffle plate component, and the single pile is provided with a structural hole for the steel pipe to pass through, and the jack drives the steel pipe to act to drive the lower section of the steel pipe to slide along the baffle plate assembly sliding groove to pass through the structural hole and enter soil around the single pile.

The protective cylinder is convenient to fix, and the cylinder wall at the upper end of the protective cylinder is welded and fixed with the steel truss.

The baffle assembly comprises an upper baffle and a lower baffle, the centers of the upper baffle and the lower baffle are provided with through holes matched with the steel shaft, the surface of the upper baffle is provided with a sliding groove matched with the lower section of the steel pipe, and the upper baffle and the lower baffle are circumferentially distributed with sector blanks and sector steel plates in a staggered manner.

In order to ensure that a gap is reserved in the vertical direction after the upper baffle and the lower baffle are closed, and the seawater is convenient to discharge, the included angle between the normal of the surface of the upper baffle fan-shaped steel plate and the axis of the steel shaft is larger than the included angle between the normal of the surface of the lower baffle fan-shaped steel plate and the axis of the steel shaft.

The soil plug is formed in the piling process and the structural damage of the baffle is avoided, the plate thickness of the upper baffle is linearly reduced from the center to the edge, and the wall thickness of the lower baffle is linearly reduced from the edge to the center.

In order to ensure uniform grouting, the surface of the lower section of the steel pipe is provided with a hole, and one end extending to a soil body is of a tip structure.

And (5) avoiding local damage of the structure, and welding stiffening ribs around the construction hole.

The flexible interface is a flexible sealing pipeline.

The construction method of the wind power single pile foundation comprises the following steps:

(1) welding the prefabricated member group at the specified position of the single pile;

(2) before piling, the upper baffle plate is overlapped with the lower baffle plate, and the fan-shaped blank spaces of the upper baffle plate are aligned with the fan-shaped blank spaces of the lower baffle plate;

(3) when the number of single pile injection hammering is obviously increased and the injection depth exceeds the depth of the lower baffle, stopping piling, and rotating the steel shaft anticlockwise to enable the fan-shaped steel plate of the upper baffle to cover the fan-shaped blank of the lower baffle, wherein the tip structures of the lower sections of the steel pipes correspond to the structure holes one by one, and the steel shaft is welded and fixed with the steel truss;

(4) stopping piling when the penetration depth of the single pile reaches the designed burial depth, starting the jack, and driving the lower section of the steel pipe to be completely pressed into the soil body by the jack;

(5) starting grouting equipment to perform grouting on the steel pipe, and pouring cement paste into a soil body through the steel pipe;

(6) and after grouting is stopped, pouring one end of the seamless steel pipe, which is far away from the soil body, and the bearing platform into a whole.

Has the advantages that: according to the single-pile foundation, the baffle plate assembly is adopted at the designed depth position inside the steel pipe to enhance the soil plug effect, the steel pipe extends out of the baffle plate position to the pile wall, and the soil body around the pile is reinforced through the steel pipe by adopting a mud jacking method, so that the vertical, horizontal and anti-torsion bearing capacity of the offshore wind power large-diameter single-pile foundation is comprehensively improved. The invention can greatly improve the uplift resistance, overturn resistance and torsion resistance bearing capacity of the single pile for manufacturing the wind generating set, shorten the pile length, enlarge the effective pile diameter, reinforce the soil body around the pile and effectively reduce the construction cost.

Drawings

FIG. 1 is an overall schematic view of the novel mono-pile foundation of the present invention;

FIG. 2 is a sectional view of the construction of the pre-pile driving member set of the present invention;

FIG. 3 is a top plan view of the steel truss arrangement of the present invention;

FIG. 4 is a top view of the arrangement of the steel casing, the seamless steel pipe and the steel shaft according to the present invention;

FIG. 5 is a schematic view of the seamless steel pipe joint of the present invention;

FIG. 6 is a top view of the upper baffle of the present invention;

FIG. 7 is a top view of a lower baffle of the present invention;

FIG. 8 is a schematic view of a steel pipe pile with structural holes and reinforcing ribs according to the present invention;

FIG. 9 is a cross-sectional view of a pre-grouting component set in accordance with the invention;

FIG. 10 is a top view of the upper shield before grouting after rotation;

FIG. 11 is a schematic view of the construction of the lower section of a seamless steel pipe;

FIG. 12 is a schematic representation of the slurry distribution after grouting.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1-2, the wind power single pile foundation disclosed by the invention comprises a single pile 2, a wind power generator set and a bearing platform 1 are fixedly connected to the upper end of the single pile 2, a prefabricated member set 3 is arranged in the single pile 2, the prefabricated member set comprises a steel truss 31, a steel casing 32, a plurality of seamless steel pipes 33, a jack 34, a steel shaft 35, an upper baffle plate 36 and a lower baffle plate 37, and the number of the seamless steel pipes in the embodiment is 8. The total length of the member group 3 can be adjusted according to the soil plug effect and the lifting requirement of the vertical bearing capacity, the length adopted in the embodiment is slightly smaller than 1/3 of the soil penetration depth of the single pile 2, and the distance between the opening of the single pile 2 and the steel truss 31 is 2 m.

As shown in fig. 3-5, the cylinder wall of the upper end of the steel casing 32 is welded and fixed to the upper surface of the steel truss 31, the steel casing 32 and the steel shaft 35 are coaxially sleeved and penetrate through the center of the steel truss 31, 8 seamless steel pipe upper sections 331 are axially distributed at intervals along the axis between the steel casing 32 and the steel shaft 35, the seamless steel pipe upper sections 331 and the middle section 332 are connected by flexible connectors 335, the top plate of the jack 34 is connected with the flexible connectors 335 of the seamless steel pipe upper sections 331 and the middle section 332, the flexible connectors 335 can be made of flexible sealed pipelines such as annular grouting pipes, and the flexible connectors provide a hinged form, only transmit force and do not transmit deformation and moment. One end of the flexible interface 335 close to the upper section of the seamless steel tube is welded and fixed at the lifting end of the jack 34, the fixed chassis of the jack 34 is welded and fixed with the lower end of the steel casing 32, and the hollow part of the jack 34 coaxially penetrates through the steel shaft 35 and the seamless steel tube 33. One end of the seamless steel tube upper section 331 and one end of the steel shaft 35 extend out of the steel casing 32, in order to ensure the stability of the seamless steel tube upper section 331 in the construction process, the steel wire can be wound to be temporarily fixed on the steel shaft 35, the steel truss 31 and the steel casing 32 provide counter force for the jack, the jack 34 is provided with a hole penetrating through the center, and the hole can meet the requirement that all seamless steel tubes and the steel shaft penetrate and can provide vertical downward thrust. The jack 34 may be a one-way or two-way hollow jack.

As shown in fig. 6-7, the baffle plate assembly comprises an upper baffle plate 36 and a lower baffle plate 37, in order to facilitate seawater discharge and ensure smooth driving process, a hole is reserved in the center of the upper baffle plate 36 and the lower baffle plate 37, 8 fan-shaped blank spaces and fan-shaped steel plates are distributed in an equidistant and staggered mode along the circumferential direction of the center, the thickness of the upper baffle plate 36 is linearly reduced from the center to the edge, the thickness of the center plate is twice that of the edge, the thickness of the edge is equal to that of the wall of the single pile 2, the thickness of the wall of the lower baffle plate 37 is linearly reduced from the edge to the center, the thickness of the edge is twice that of the center, and the thickness of the center plate is equal to that of the wall of the single pile 2. The center of the upper baffle plate 36 is coaxially welded and fixed with the steel shaft, the other end is free, and the diameter of the upper baffle plate is slightly smaller than that of the lower baffle plate 37; the outer edge of the lower baffle plate 37 is welded and fixed with the single pile 2, and the other end is coaxially sleeved at the tail end of the steel shaft 35. In the initial stage of piling. In order to discharge seawater and ensure that the piling process is carried out smoothly, the upper baffle plate 36 is right opposite to the lower baffle plate 37, and the bottom end of the component group forms a form of 8 sector-shaped blank spaces which are symmetrically distributed at equal intervals in a staggered manner along the center. The included angle between the normal of the plane of each fan-shaped steel plate of the upper baffle plate 36 and the axis of the steel shaft is required to be larger than the included angle corresponding to the lower baffle plate. In this embodiment, the included angles between the normal of the plane where the 8 steel plates of the upper baffle 36 are located and the axis of the steel shaft are all 10 °, and the included angles between the normal of the plane where the 8 steel plates of the lower baffle are located and the axis of the steel shaft are all 5 °. The 8 steel sheet surfaces of overhead gage all open chisel have with seamless steel pipe assorted spout 361, 8 seamless steel pipe middle sections and hypomere adopt flexible interface sealing connection in spout department, for guaranteeing that the mud jacking is even, seamless steel pipe hypomere 334 surface gathers the aperture, the one end that extends to the soil body is most advanced structure, seamless steel pipe hypomere 334 can be followed the spout and slided, for guaranteeing seamless steel pipe upper segment, the middle section, the hypomere links to each other and forms complete mud jacking passageway, the junction is flexible interface connection, flexible interface material can adopt flexible sealing pipeline materials such as annular mud jacking pipe, its length is approximately equal to the diameter (D) of twice seamless steel pipe, flexible interface is the transmission power only of articulated form, do not transmit deformation and moment.

As shown in fig. 8, the base of the jack 34 is welded and fixed with the lower end of the steel casing 32, the middle section of the seamless steel pipe is pushed downwards by the other end, the lower sections of the 8 seamless steel pipes are linked to slide along the corresponding sliding grooves, penetrate through the structural holes and are jacked into the soil around the single pile 2, when the lower section 333 of the seamless steel pipe completely enters the soil, the included angle between the middle section of the seamless steel pipe and the axis of the steel shaft is 30 degrees, the length of the lower section 333 of the seamless steel pipe is equal to the radius of the single pile 2, the single pile 2 is provided with structural holes matched with the lower section of the seamless steel pipe near the upper baffle, and the stiffening ribs 21 are welded around the structural holes to prevent the local structure of the single pile from being damaged.

As shown in fig. 9-10, when the number of single pile penetration hammering is significantly increased and the penetration depth exceeds 2/3 of the designed burial depth, the steel shaft is rotated counterclockwise by 22.5 degrees, so that the upper baffle 36 covers the blank space on the lower baffle 37, the lower segments and the middle segments of 8 seamless steel pipes are rotated along with the upper baffle, the tip structures of the lower segments of 8 seamless steel pipes are in one-to-one correspondence with the structural holes, and the slight rotation of the middle segments of 8 seamless steel pipes does not affect the linkage effect of a jack on the middle segments and the lower segments. The upper baffle 36 covers the lower baffle 37, so that the soil mass in the single pile is prevented from upwelling in the piling process, the soil plug effect is enhanced, and the bearing capacity of the single pile is improved. Because the inclined angles of the surfaces of the upper baffle plate 36 and the lower baffle plate 37 are different, a certain gap is reserved between the two plates in the vertical direction, so that the water pressure of the soil body in the pile in the piling process is dissipated, and the smooth construction is ensured. In the embodiment, the diameter of the steel pile casing is 1/6-1/4 of the diameter of the single pile, and the wall thickness of the single pile are 1/8-1/6 of the wall thickness of the single pile, and the steel pile casing can be adjusted according to the actual size of the single pile.

During construction, the invention comprises the following steps:

(1) welding the member group at the designated position of the single pile, and transporting the member group to a designated place for construction after the member group is assembled with the single pile;

(2) before piling, the upper baffle plate is overlapped with the lower baffle plate, and at the moment, 8 blank spaces of the upper baffle plate are aligned with 8 blank spaces of the lower baffle plate;

(3) when the number of the single pile penetration hammering is obviously increased and the penetration depth exceeds 2/3 of the designed burial depth, stopping piling, and rotating the steel shaft anticlockwise to enable 8 steel plates of the upper baffle plate to cover 8 blank spaces of the lower baffle plate, wherein the tip structures of the lower sections of the 8 seamless steel pipes correspond to the structure holes one by one, and the steel shaft and the steel truss are welded firmly;

(4) stopping piling until the penetration depth of the single pile reaches the designed buried depth, starting a jack, and completely pressing the lower sections of the 8 seamless steel pipes into the soil body;

(5) starting grouting equipment, grouting 8 seamless steel pipes, and pouring cement slurry into a soil body;

(6) and after grouting is stopped, pouring one end of each of the 8 seamless steel pipes close to the fan and a bearing platform into a whole.

Claims (9)

1. The wind power single pile foundation comprises a single pile (2) and is characterized in that a prefabricated member group (3) is arranged in the single pile (2) and comprises a steel truss (31), a steel shaft (35), a pile casing (32) and a baffle assembly, the steel truss (31) and the baffle assembly are respectively fixed on the upper side and the lower side of the single pile (2), the steel shaft (35) penetrates through the steel truss (31) and the center of the baffle assembly to be fixed, the pile casing (32) is sleeved on the upper section of the steel shaft (35), a jack (34) is fixed at the lower end of the pile casing (32), a plurality of steel pipes (33) are arranged between the steel shaft (35) and the pile casing (32) at intervals along the circumferential direction, each steel pipe comprises a steel pipe upper section (331), a steel pipe middle section (332) and a steel pipe lower section (333) which are connected through a flexible interface, the steel pipe middle section (332) is connected with a top plate of the jack (34), the steel pipe lower section (333) extends along the surface of the baffle assembly and can slide along the baffle assembly, a structural hole (22) for the steel pipe (33) to pass through is formed in the single pile (2), and the jack (34) drives the steel pipe lower section (333) to slide along the baffle assembly sliding groove to pass through the structural hole and enter soil around the single pile (2).

2. The wind power single pile foundation according to claim 1, characterized in that the wall of the upper end of the casing (32) is welded and fixed with the steel truss (31).

3. The wind-powered electricity generation single pile basis of claim 1, characterized in that, the baffle subassembly includes overhead gage (36) and lower baffle (37), overhead gage (36) and lower baffle (37) center are provided with the through-hole with steel axle (35) adaptation, the spout (361) with steel pipe lower segment adaptation is seted up on overhead gage (36) surface, overhead gage (36) and lower baffle (37) are along central circumference crisscross distribution fan-shaped blank and fan-shaped steel sheet.

4. A wind power single pile foundation according to claim 3, wherein the included angle between the normal of the sector-shaped steel plate surface of the upper baffle (36) and the axis of the steel shaft is larger than the included angle between the normal of the sector-shaped steel plate surface of the lower baffle (37) and the axis of the steel shaft.

5. The wind power single pile foundation according to claim 1, characterized in that the plate thickness of the upper baffle (36) decreases linearly from the center to the edge, and the plate thickness of the lower baffle (7) decreases linearly from the edge to the center.

6. The wind power single pile foundation according to claim 1, characterized in that the surface of the lower section (333) of the steel pipe is provided with holes, and one end extending to the soil body is of a tip structure.

7. Wind power single pile foundation according to claim 1, characterised in that stiffening ribs (21) are welded around the structural holes (22).

8. The wind-powered single pile foundation of claim 1, wherein the flexible interface is a flexible sealed conduit.

9. The construction method of the wind power single pile foundation according to claim 1, characterized by comprising the steps of:

(1) welding the prefabricated member group at the specified position of the single pile;

(2) before piling, the upper baffle plate is overlapped with the lower baffle plate, and the fan-shaped blank spaces of the upper baffle plate are aligned with the fan-shaped blank spaces of the lower baffle plate;

(3) when the number of the single pile injection hammering is obviously increased and the injection depth exceeds the depth of the lower baffle plate, the pile driving is suspended, the steel shaft is rotated anticlockwise, the fan-shaped steel plate of the upper baffle plate covers the fan-shaped blank of the lower baffle plate, the tip structures of the lower sections of the steel pipes correspond to the structural holes one by one, and the steel shaft and the steel truss are welded and fixed;

(4) stopping piling when the penetration depth of the single pile reaches the designed buried depth, starting a jack, and driving the lower section of the steel pipe to be completely pressed into the soil body by the jack;

(5) starting grouting equipment to carry out grouting on the steel pipe, and pouring cement paste into a soil body through the steel pipe to reinforce;

(6) and after grouting is stopped, pouring one end of the seamless steel pipe, which is far away from the soil body, and the bearing platform into a whole.

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