Background
At present, in offshore wind power generation projects, fixed foundation structures generally have forms of pile foundations, gravity foundations, jacket foundations, barrel foundations and the like. With the development of offshore wind power towards deep and far sea, the excellent bearing performance and economy of the jacket foundation are highlighted in a deep water area. The offshore wind power jacket foundation structure mostly adopts a multi-pile foundation, and the load magnitude borne by the jacket foundation is continuously increased along with the increase of the application water depth of the jacket foundation, so that the pile length and the pile weight of the multi-pile foundation of the jacket are continuously increased. The difficulty and risk of offshore pile driving construction are greatly increased by the excessive pile length and pile weight. Therefore, how to optimize the form of the pile foundation, the bearing capacity of the pile foundation can be exerted to the maximum extent, and the construction difficulty is reduced, so that the key problem in the design of the jacket foundation is solved.
SUMMERY OF THE UTILITY MODEL
The utility model discloses exerting oneself in solving the technical problem who improves jacket pile foundation bearing capacity and reduce the construction degree of difficulty, provide a jacket pile foundation structure soon, can reach material saving, improve the bearing capacity, reduce the engineering time, improve the purpose of efficiency of construction.
In order to solve the technical problem, the utility model discloses a following technical scheme realizes:
a jacket pile foundation structure comprises a jacket, wherein the jacket is formed by connecting main legs and a supporting structure, and the outer side of the bottom of each main leg of the jacket is welded with a skirt sleeve and is connected with a pile through the skirt sleeve; the pile comprises a central pile, a stiffening rib plate and a rotation bearing blade, wherein the stiffening rib plate is arranged on the outer side of the top of the central pile, and the rotation bearing blade is arranged at different heights on the outer side of the central pile according to the soil condition of a site in place; after the screwing pile is inserted into the skirt sleeve, the screwing pile is connected with the skirt sleeve in a grouting mode through the stiffening rib plates; the jacket bottom is provided with prevents sinking the structure, prevent sinking the structure including weld in the heavy board of preventing of main leg, the welding of heavy board bottom has the floor.
Furthermore, the driving and rotating piles can form a regular polygon on the horizontal plane according to the connecting line of the central points of the driving and rotating piles.
Further, the jacket is provided with a water injection hole.
Furthermore, a soft soil layer exists in a foundation in-place site, and at least one group of the rotary bearing blades are arranged on the center pile corresponding to the elevation where the soft soil layer is located in the foundation in-place state.
Further, a hard soil layer exists in a foundation in-place site, and the spinning bearing blades are arranged at least at the bottom of the central pile.
Further, the rotation bearing blades are inclined, are uniformly arranged around the axis of the central pile, are consistent in inclination direction, and have inclination angles of 30-150 degrees.
Further, the rotary bearing blades are spiral and are uniformly arranged around the axis of the central pile, the rotating direction of the rotary bearing blades is consistent, and the spiral angle of the rotary bearing blades ranges from 18 degrees to 360 degrees.
Furthermore, the anti-sinking plate is provided with water permeable holes.
The utility model has the advantages that:
the jacket spinning pile foundation structure of the utility model utilizes the spinning pile to replace the traditional single pile, the spinning pile can be used for general pile driving equipment for pile driving construction, the spinning pile can easily enter the ground under the interaction of the spinning bearing blades and the soil body, and the effective load area of the central pile is far larger than the sectional area of the single pile with equal diameter after the spinning pile is in place, so that the jacket spinning pile foundation structure has larger anti-pulling bearing capacity; when the uplift bearing capacity is remarkably improved, the length and the diameter of the pile are greatly shortened compared with the traditional single pile, and a large amount of steel is saved. The utility model discloses a beat and revolve grout between stake and the skirt stake sleeve and be connected, guarantee to beat the wholeness of revolving stake and jacket, ensure the effective transmission of structure load. The utility model discloses a box prevent sinking structure and prevent that heavy board has stronger cling compound bearing capacity than the tradition to possess the effect that slows down the speed of sinking, make the jacket construction of sinking have higher security and stability.
Detailed Description
In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings:
example 1
As shown in fig. 1 to 3, the embodiment discloses a jacket spinning pile foundation structure for offshore wind power, which mainly comprises a jacket 1, spinning piles 2, a skirt sleeve 3 and an anti-sinking structure 4, wherein a plurality of identical spinning piles 2 can form a regular polygon on a horizontal plane according to a central point connecting line, the top of each spinning pile 2 is connected with the jacket 1 through the skirt sleeve 3, and the anti-sinking structure 4 is arranged at the bottom of the jacket 1.
The jacket 1 is formed by connecting a plurality of main legs 101 and a plurality of supporting structures 102, and the main legs 101 and the supporting structures 102 are made of round steel pipes. The diameter of the main leg 101 and the support structure 102 is in the range of 500-3000mm, and the wall thickness is in the range of 15-100 mm; the main leg 101 diameter is typically larger than the support structure 102 diameter. The number of main legs 11 is the same as the number of driven piles 2, typically 3-6. Usually, the main leg 101 is reserved with a water injection hole for injecting water into the jacket 11 manually during the sinking process to reduce the buoyancy of the jacket 1; the jacket 11 can also be leveled by controlling the amount of water injected in the different main legs 101.
The swing pile 2 includes a center pile 201, a stiffening rib 202, and a swing bearing blade 203. Generally, the central pile 201 of the driving and rotating pile 2 is a round steel pipe, the diameter of the pile is 1-10m, the mud entering length is 10-100m, and the thickness is 15-100 mm.
The stiffening rib plate 202 is arranged outside the top of the central pile 201, the height of the stiffening rib plate 202 is not more than the height of the skirt sleeve 3, and the sum of the diameter of the central pile 201 and the width of the stiffening rib plate 202 is less than the inner diameter of the skirt sleeve 3. The stiffening rib plates 202 are uniformly distributed around the axial line of the central pile 201 in the radial direction, the number of the stiffening rib plates is 2-20, the width of the stiffening rib plates is 0.1-10m, and the thickness of the stiffening rib plates is 5-50 mm. The stiffening rib plates 202 are made of steel structures and are connected with the central pile 201 through welding. The contact area of stiffening rib board 202 can increase and grouting material improves the joint strength who revolves stake 2 and skirt sleeve 3 to guarantee to beat the wholeness of revolving stake 2 and jacket 1, ensure the effective transmission of structural load.
In this embodiment, the spin bearing blades 203 are disposed at the bottom of the center pile 201. One or more layers of the rotation bearing blades 203 may be arranged at different heights outside the central pile 201 according to the soil conditions of the site where different foundations are located. If a soft soil layer exists in a foundation in-place site, generally, the rotary bearing blades 203 are arranged at the height of the central pile 201 corresponding to the position of the soft soil layer in the in-place state of the foundation, and the rotary bearing blades 203 provide main bearing capacity after being screwed into the foundation, so that the length of the central pile 201 can be reduced, and the construction is convenient. The utility model discloses the soft soil layer that indicates include but not limited to be in the soft stickness soil layer of moulding/flowing the state of moulding, be in loose state's sand soil layer, untreated fill out soil and other high compressibility soil layers. If a hard soil layer with high strength and difficult pile driving exists in a foundation in-place site, in general, the rotary bearing blades 203 are arranged at the bottom of the central pile 201, the bottom of the central pile 201 falls on the top of the hard soil layer after the foundation is in place, the rotary bearing blades 203 provide main bearing capacity, the central pile 201 does not need to be inserted into the hard soil layer, excavation construction is not needed, meanwhile, the length of the central pile 201 is reduced, and construction is convenient. The utility model discloses the hardpan that points to includes but not limited to rock layer, coarse gravel layer, metalling. The width of the rotation bearing blade 203 can be changed along the elevation according to the soil body strength of different soil layers and the stress of the central pile, the width of the weak part of the soil body is wider, and the width of the strong part of the soil body is narrower.
The swirl bearing blades 203 are steel structures and can be inclined or spiral. As shown in fig. 4, the inclined spin bearing blades 203 are provided in plural, and are uniformly arranged around the axis of the central pile 201 and have the same inclination direction; the inclined rotary bearing blade 203 has simple processing and blanking, high processing speed and short manufacturing period. Preferably, each inclined spin bearing blade 203 is a planar sheet structure, the inner side of each inclined spin bearing blade is welded to the surface of the central pile 201, and the outer side of each inclined spin bearing blade is parallel to the intersecting line of the inner side and the central pile 201, so that the width of each spin bearing blade 203 is consistent along the way. Preferably, the number of the inclined rotary bearing blades 203 is 2-20, the inclination angle is 30-150 degrees, the width is 0.1-10m, and the thickness is 1-200 mm. More preferably, the inclination angle of the inclined rotary bearing blade 203 is 45-135 degrees, and the inclination angle in the range can better form an interaction mode with the soil body, so that the rotary bearing blade 203 is more beneficial to shearing the soil body. As shown in fig. 5, the helical rotation bearing blades 203 comprise at least one, which are uniformly arranged around the axis of the central pile 201 and have consistent rotation direction; the spiral screwing bearing blade 203 can effectively reduce the sinking resistance of the screwing pile 2 and reduce the hammering energy and times in the screwing process. Preferably, the number of the spiral rotation bearing blades 203 is 1-20, the spiral angle is 18-360 degrees, the width is 0.1-10m, and the thickness is 1-200 mm. More preferably, the spiral angle of the spiral rotation bearing blade 203 is 45-135 degrees, and the inclination angle in the range can better form an interaction mode with the soil body, so that the rotation bearing blade 203 is more beneficial to shearing the soil body.
During construction, the rotary pile 2 can be driven by using general pile driving equipment, the rotary pile 2 automatically rotates downwards to enter the soil body under the interaction of the rotary bearing blades 203 and the soil body, and the rotary bearing blades 203 with large cross-sectional areas provide large bearing capacity for the rotary pile 2 after the rotary bearing blades 203 are in place.
Skirt pile sleeve 3 is circular steel pipe, and skirt pile sleeve 3's internal diameter is greater than the biggest external diameter (the sum of central pile 201 diameter and the width of beating and rotating bearing blade 203) of beating rotary pile 2, guarantees to beat rotary pile 2 and can insert skirt pile sleeve 3 smoothly. The skirt pile sleeve 3 is arranged outside each main leg 101 of the jacket 1 and is connected to the bottom of the main leg 101 by welding. The driven pile 2 is inserted into the skirt pile casing 3 and then connected with the skirt pile casing 3 through the stiffening rib plate 202 in a grouting manner, so that the driven pile 2 and the jacket 1 are connected into a whole. The gaps among the stiffening ribs 7 are filled with the grouting material, the contact area between the driving pile 2 and the grouting material can be increased by the stiffening ribs 7, and the grouting material is common cement paste, epoxy cement paste or high-strength grouting material.
Referring to fig. 6, the anti-sinking structure 4 is a box-shaped structure with an open bottom, and includes an anti-sinking plate 401 and a rib plate 402, the anti-sinking plate 401 is formed by welding and assembling steel plates, the thickness of the anti-sinking plate 401 is 15-50mm, and the thickness of the rib plate 402 is 5-30 mm. The anti-sinking plate 401 is connected with the main leg 101 of the jacket 1 through welding, and the rib plate 402 is welded on the bottom surface of the anti-sinking plate 401 to form a box-shaped structure with an open bottom. The corners of the anti-settling plate 401 are provided with water permeable holes, the diameter of each water permeable hole is 5-20mm, and the water permeable holes can enable water in the anti-settling structure 4 to be smoothly discharged in the leveling process of the jacket 1 so as to ensure that the anti-settling plate 401 completely contacts a mud surface.
The construction method of the jacket spin pile foundation structure specifically comprises the following steps:
(1) prefabrication of the jacket 1, the driven piles 2, the skirt pile sleeves 3 and the anti-settling structure 4 is completed on land, and connection of the main legs 101 of the jacket 1 with the skirt pile sleeves 3 and the anti-settling structure 4 is completed.
(2) The integral structure formed by the jacket 1, the skirt sleeves 3 and the anti-sinking structure 4 is hoisted to a floating crane or other barge, transported to an installation site, and accurately positioned by using an anchoring system.
(3) After the positioning, the overall structure consisting of the jacket 1, the skirt sleeve 3 and the anti-sinking structure 4 is lifted and lowered by utilizing the hoisting equipment, and water is injected into the jacket 1 through the water injection holes, so that the sinking of the overall structure is realized. In the sinking process, the anti-sinking structure 4 can play a role in blocking water, so that the sinking speed of the structure is reduced, and the jacket 1 is guaranteed to sink stably. After sinking to the mud surface of the anti-sinking structure 4, water is continuously injected into the jacket 1 through the water injection holes, and the leveling of the jacket 1 is realized by controlling the water injection amount of each main leg 101 of the jacket 1 until the ribbed plate 402 completely enters the mud surface.
(4) And inserting the rotary pile 2 into the mud surface through the skirt pile sleeve 3, and piling by adopting universal piling hammer equipment. The rotary pile 2 is inserted into a soil layer and rotates under the interaction of the rotary bearing blades 203 and the soil body, and the torque force of the rotary bearing blades 203 is gradually transferred into the foundation; during initial piling, the steel rotary bearing blade 203 has a certain shearing effect on the foundation, during the piling process, the rotary bearing blade 203 rotates along with the hammering depth to generate a certain disturbance effect on the soil around the foundation of the central pile 201, so that the strength of the surrounding soil is weakened, and the rotary pile 2 is gradually rotated into the foundation by using the hammering effect of the piling hammer and the torsion of the rotary bearing blade 203 until the reinforcing rib plate 202 at the top of the rotary pile 2 completely enters the skirt pile casing 3.
(5) The grouting material is utilized to perform underwater grouting in the skirt sleeve 3, the grouting material is common cement paste, epoxy cement paste or high-strength grouting material, so that the reinforcing rib plate 202, the central pile 201 and the skirt sleeve 3 are tightly connected, the pile 2 and the jacket 1 are integrated, and finally construction is completed.
Example 2
As shown in fig. 7, embodiment 2 differs from embodiment 1 only in the specific structure of the pile 2.
According to soil quality parameters of a soft soil layer, a plurality of different elevations are selected to arrange a plurality of groups of rotation bearing blades 203 on the rotation pile 2. And each group of the swirling bearing blades 203 are designed to have different heights and widths according to the height and the bearing capacity of the soil layer, the thicker the soil layer is, the higher the height of the swirling bearing blades 203 is, the softer the soil layer is, the larger the width of the helical blades is, so that the effect of effectively reinforcing the weak soil body and improving the bearing capacity can be achieved.
Although the preferred embodiments of the present invention have been described with reference to the accompanying drawings, the present invention is not limited to the above embodiments, which are only illustrative and not restrictive, and those skilled in the art can make various changes without departing from the spirit and the scope of the invention as claimed.