Lifting type mixed tower foundation structure combining beams, barrels and plates

Abstract

The invention discloses a lifting type mixed tower foundation structure combining beams, cylinders and plates. The mixed tower foundation is mainly composed of a plurality of prefabricated triangular trusses, a bottom plate, a plurality of prefabricated wall bodies, a top ring beam, a bottom ring beam and prestressed steel strand assemblies. The prefabricated triangular truss is connected with the ground through a cast-in-place bottom ring beam and a cast-in-place bottom plate, and the prefabricated wall body and the prefabricated triangular truss are connected through a cast-in-place wall body connecting part to jointly form a closed structure. The prefabricated triangular truss and the top of the prefabricated wall are connected through a cast-in-place top circular rector to form a stress whole, the prestressed steel strand assembly penetrates through a bracket of the prefabricated triangular truss and the upper tower body part from bottom to top, and the lower portion of the prestressed steel strand assembly is fixed to the bottom of the bracket of the prefabricated triangular truss. The connecting structure has the beneficial effects of reliable connection, reasonable force transmission, multiple prefabricated parts, few molds, convenience in construction and maintenance and low manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of wind power hybrid tower foundation technology, specifically to a raised hybrid tower foundation structure combining beams, tubes, and slabs. Background Technology

[0002] In fields such as wind power generation, the performance of hybrid tower foundations is crucial for the stable operation of the entire power generation system. With the continuous development of wind power technology, wind farm construction is gradually expanding into areas with complex terrain and harsh environments, which places higher demands on the design and construction of hybrid tower foundations. Currently, traditional gravity foundations and beam-slab foundations have revealed many problems that cannot be ignored in practical applications.

[0003] Traditional gravity foundations rely primarily on their own massive weight to withstand the loads of the superstructure and external forces such as wind and earthquakes. However, this type of foundation consumes a large amount of concrete, resulting in a huge foundation volume. On the one hand, material costs increase significantly; on the other hand, on-site concrete pouring is labor-intensive and inefficient. Furthermore, gravity foundations require extremely high soil bearing capacity and are prone to significant settlement on soft soil, causing the tower to tilt, severely affecting the wind turbine's power generation efficiency, and even threatening its safe operation. For example, in wind farms in soft soil areas such as coastal mudflats, gravity foundations frequently experience tower verticality issues due to uneven soil settlement, increasing maintenance costs and safety hazards.

[0004] While beam-slab foundations address some of the drawbacks of gravity foundations, they also have their own inherent limitations. The beams and slabs of beam-slab foundations are typically cast-in-place on-site, involving complex construction processes and significant susceptibility to external factors such as weather. Furthermore, vibrating the concrete during high-altitude pouring presents challenges in ensuring its density and uniformity, potentially leading to honeycombing, pitting, and other quality issues that affect the beam's load-bearing capacity and durability. In addition, the structural form of beam-slab foundations results in relatively low overall stiffness, making them prone to cracking under long-term dynamic loads from wind turbines, thus reducing the foundation's lifespan and increasing subsequent maintenance costs.

[0005] In summary, existing gravity foundations and beam-slab foundations are no longer sufficient to meet the growing development needs of the wind power industry. There is an urgent need to develop a new type of wind power foundation structure to improve the foundation's load-bearing capacity, stability, and durability, while reducing construction and maintenance costs and adapting to complex and ever-changing engineering environments. Summary of the Invention

[0006] To address the above problems, this invention provides a raised hybrid tower foundation that combines beams, tubes, and slabs.

[0007] A raised beam-tube-slab hybrid tower foundation structure, characterized by raised precast beams, cylindrical tubes, a base slab, connecting pile caps, buttress columns, prestressed steel strand assemblies, and prestressed anchor bolt assemblies.

[0008] The raised precast beam has a rectangular cross-section with an inclination angle of 45-55 degrees. The length, height, and width of the beam are designed according to the requirements of the superstructure load and structural layout.

[0009] Furthermore, the raised precast beams are cast using molds laid flat to ensure the quality of vibration and to guarantee the homogeneity and strength of the beam body.

[0010] The cylindrical body is made of reinforced concrete, and the inner diameter, outer diameter and height of the body are determined based on the overall design of the tower and geological conditions.

[0011] Furthermore, doorways can be installed inside the cylinder.

[0012] Furthermore, the cylindrical body is placed above and abuts the ground plane, serving as the main vertical load-bearing structure of the foundation, bearing and transmitting the load of the upper structure downwards.

[0013] The base slab is constructed using cast-in-place concrete, with a thickness of 500-1000mm.

[0014] Furthermore, a crisscrossing steel mesh is installed inside the base plate according to design requirements.

[0015] Furthermore, the specifications, spacing, and other parameters of the reinforcing mesh are determined by calculation based on the load-bearing capacity and crack resistance requirements of the base slab.

[0016] Furthermore, the base plate is cast in place as a whole with the cylindrical body and the bottom of the raised precast beam, and is placed above the ground plane and abuts against the ground plane, which plays the role of distributing the load and stabilizing the foundation.

[0017] The connecting pier is cast in place at the connection between the cylindrical body and the raised precast beam.

[0018] Furthermore, the connecting pier has through-holes of prestressed steel strands and prestressed anchor bolts, which are distributed circumferentially.

[0019] The buttress columns are distributed circumferentially along the cylindrical body and are cast together with the cylindrical body as a whole.

[0020] Furthermore, the cross-sectional shape of the buttress column can be selected according to the actual stress conditions, such as rectangular or L-shaped, and it is made of reinforced concrete.

[0021] Furthermore, longitudinal reinforcement bars are installed inside the column to ensure its strength and stability.

[0022] Furthermore, the upper part of the raised precast beam rests on the buttress column, corresponding one-to-one with the buttress column in the circumferential direction. The buttress column serves to support the precast beam and assist in the transfer of load.

[0023] The prestressed steel strand assembly is arranged circumferentially along the connecting bearing and passes through the connecting bearing.

[0024] Furthermore, the prestressed steel strand assembly is arranged in a circumferentially uniform manner within the connecting pier, with the lower tensioning point positioned above ±0.

[0025] The prestressed anchor bolt assembly is arranged circumferentially along the connecting bearing platform, penetrating the connecting bearing platform and the cylindrical body.

[0026] Furthermore, the prestressed anchor bolt assembly is pre-embedded in the bottom of the cylindrical body, and an anchor plate is configured when fixing it to the top of the connecting pier.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention prefabricates the beams that are difficult to cast, and casts them with a flat mold of equal width beams. The vibration is sufficient, and the quality of the beam is better than that of traditional cast-in-place, and the construction quality is better.

[0028] (2) The present invention adopts raised precast beams with higher beam support, which improves the rigidity of the foundation. The foundation with tube body optimizes force transmission, which can reduce the cost of the superstructure and balance stability and economy.

[0029] (3) The present invention can open a doorway in the cylindrical tube between the raised precast beams, so that the upper tube does not need to be opened, which simplifies the design, avoids the doorway weakening the structure, and improves reliability and aesthetics.

[0030] (4) The steel strand of the mixed tower cylinder of the present invention can be tensioned above the natural backfill, avoiding the trouble of basement water leakage, making construction and later maintenance more convenient and safe, reducing costs and increasing efficiency.

[0031] (5) The present invention adopts a combination of precast beams and cast-in-place construction. The precast beams are produced in the factory and constructed on site in parallel, which is easy to install and significantly shortens the construction period compared with pure cast-in-place beams and slabs. Attached Figure Description

[0032] Figure 1 General layout plan for a raised, combined beam, tube, and slab tower foundation; Figure 2 A 3D model of the raised precast beam; Figure 3 A three-dimensional drawing of a cylindrical body; Figure 4 This is a 3D view of the base plate; Figure 5 3D diagram of the connecting pier; Figure 6 A 3D diagram of a raised tower combining beams, tubes, and slabs after backfilling; Figure 7 Cross-sectional view of a raised, beam-tube-slab hybrid tower foundation; In the diagram: 1. Elevated precast beam, 2. Cylindrical tube, 3. Buttress column, 4. Base slab, 5. Connecting pile cap, 6. Prestressed steel strand duct, 7. Prestressed anchor bolt duct, 8. Upper tower, 9. Doorway, 10. Prestressed steel strand, 11. Prestressed anchor bolt, 12. Upper beam reinforcement, 13. Bottom beam reinforcement, 21. Top reinforcement of the cylindrical tube, 22. Bottom radial reinforcement of the cylindrical tube, 41. Base slab connection, 42. Natural backfill, 51. Tower connection, 52. Cover plate connection. Detailed Implementation

[0033] Example 1 The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0034] This invention provides a raised composite tower foundation combining beams, tubes, and slabs. An embodiment is given below to describe the invention in detail.

[0035] like Figure 1 The four different forms of the raised beam-tube-slab hybrid tower foundation structure shown include the form with buttresses and prestressed anchor bolts, the form with buttresses but without prestressed anchor bolts, the form without buttresses but with prestressed anchor bolts, and the form without buttresses but without prestressed anchor bolts.

[0036] like Figures 1-7 The illustrated raised beam-tube-slab composite tower foundation includes a cylindrical tube 2. The inner diameter, outer diameter, and height of the cylindrical tube are determined based on the overall tower design and geological conditions. Custom-made steel or wooden formwork is used for formwork support. Reinforcing bars are tied within the formwork. Top reinforcing bars (as shown in Figure 21) are installed at the top of the cylindrical tube, and bottom radial reinforcing bars (as shown in Figure 22) are installed at the bottom. Other structural reinforcing bars are arranged according to design requirements to form a complete reinforcing steel skeleton. Prestressed anchor bolt assemblies are pre-embedded at the bottom of the cylindrical tube according to the designed positions and spacing, ensuring accurate positioning and reliable connection with the reinforcing steel skeleton to prevent displacement during concrete pouring. After inspection and approval, concrete is poured in layers and cured promptly. Doorways are opened at appropriate locations within the tube as needed to ensure structural stability.

[0037] Based on the superstructure load and structural layout, the dimensions and inclination angle of the precast beams are designed. The raised precast beams are cast in the prefabrication plant using specially designed flat molds. A steel reinforcement cage, including the upper reinforcement 11 and the bottom reinforcement 12, is arranged within the mold to ensure that the specifications, quantity, and spacing of the reinforcement meet design requirements. Because the beams are cast flat, the vibration quality is effectively guaranteed, resulting in uniform and dense concrete, ensuring the homogeneity and strength of the beam. After the concrete is poured, it is cured and demolded after reaching the design strength. Upon arrival at the site, a crane is used to place the raised precast beam 1 onto the buttress column 3, ensuring a secure connection. Limiters may be added at the placement points as needed.

[0038] Construction of the base slab 4 is carried out at the bottom of the already installed cylindrical tube and raised precast beam. The base slab is constructed using cast-in-place concrete, with a thickness controlled between 500-1000mm. Before pouring the concrete, a crisscrossing steel mesh, configured according to design requirements, is laid at the bottom of the foundation. The specifications, spacing, and other parameters of the steel bars are determined by calculation based on the load-bearing and crack resistance requirements of the base slab. The base slab concrete is vibrated using equipment such as a plate vibrator to ensure the density and flatness of the concrete. At the connection 41 between the base slab and the bottom of the cylindrical tube and raised precast beam, special treatment should be carried out, such as roughening and setting connecting steel bars, to ensure a firm connection between the base slab and the superstructure, forming a whole, and jointly playing the role of distributing the load and stabilizing the foundation.

[0039] At the connection between the cylindrical tube and the raised precast beam, formwork for the connecting pier 5 is erected. The formwork should have sufficient strength, rigidity, and stability to ensure no deformation during concrete pouring. Reinforcing bars for the connecting pier are tied inside the formwork to form a reinforcing steel skeleton. Through-holes 6 for prestressed steel strands and 7 for prestressed anchor bolts are pre-drilled according to design requirements, ensuring accurate positioning and uniform circumferential distribution of the holes. After inspection and approval, the concrete for the connecting pier is poured. Concrete pouring should be continuous, using equipment such as vibrators to ensure compaction. During concrete pouring, care should be taken to protect the prestressed ducts to prevent damage. After the concrete for the connecting pier reaches its design strength, the prestressed steel strand assemblies are inserted into the prestressed steel strand ducts 6 according to design requirements. The prestressed steel strand assemblies are evenly distributed circumferentially within the connecting pier, with the elevation of the lower tensioning point controlled above 42mm of the natural fill soil. Prestress is applied to the steel strands using tensioning equipment, and then anchored using suitable anchors to generate pre-compression stress in the foundation structure, improving the foundation's crack resistance and bearing capacity. The prestressed anchor bolt assembly is connected to the pre-embedded portion at the bottom of the cylindrical body through prestressed anchor bolt channels 7, and an anchor plate is installed on the top of the connecting platform to ensure a firm and reliable connection, allowing the cylindrical body and the connecting platform to work together.

[0040] like Figure 6As shown, the raised tower, composed of beams, cylinders, and slabs, is constructed after backfilling. The bottom of the upper tower cylinder 8 is located at the tower body connection 51. During construction, high-strength grout is used to fill the tower body connection, and silicone sealant is applied. The doorway 9 is located between the raised precast beams, above the natural backfill 42. The above embodiments are merely illustrative of the concept and implementation of the present invention and are not intended to limit it. Under the concept of the present invention, technical solutions without substantial changes are still within the scope of protection.

Claims

1. A raised, beam-tube-slab hybrid tower foundation structure, characterized in that: Includes raised precast beams, cylindrical tubes, base plates, connecting bearing platforms, buttress columns, prestressed steel strand assemblies, and prestressed anchor bolt assemblies; The cylindrical body is placed above and abuts the ground plane. The buttress columns are distributed circumferentially along the cylindrical body and are cast integrally with the cylindrical body. The upper part of the raised precast beam rests on the buttress columns and corresponds to each buttress column circumferentially. The base plate is cast integrally with the cylindrical body and the bottom of the raised precast beam, placed above and abutting the ground plane. The connecting platform is cast in place at the connection between the raised precast beam and the cylindrical body. The prestressed steel strand assembly is arranged circumferentially along the connecting platform and passes through the connecting platform. The prestressed anchor bolt assembly is arranged circumferentially along the connecting platform and passes through the connecting platform and the cylindrical body.

2. The raised beam-tube-slab combined hybrid tower foundation structure according to claim 1, characterized in that, The raised precast beam has a rectangular cross-section with an inclination angle of 45-55 degrees. The length, height, and width of the beam are designed according to the requirements of the upper load and structural layout. The raised precast beam is cast using a mold placed flat.

3. The raised beam-tube-slab combined hybrid tower foundation structure according to claim 1, characterized in that, The base slab is constructed by cast-in-place concrete with a thickness of 500-1000mm. The base slab is equipped with a crisscrossing steel mesh according to the design requirements. The relevant parameters of the steel mesh are determined by calculation based on the load-bearing and crack resistance requirements of the base slab.

4. The raised beam-tube-slab combined hybrid tower foundation structure according to claim 1, characterized in that, The cylindrical body is made of reinforced concrete. The inner diameter, outer diameter and height of the body are determined according to the overall design of the tower and geological conditions. Door openings are set inside the body.

5. The raised beam-tube-slab combined hybrid tower foundation structure according to claim 1, characterized in that, The connecting pier is cast in place at the connection between the cylindrical body and the raised precast beam. The connecting pier has through-holes for prestressed steel strands and prestressed anchor bolts, which are distributed along the circumference.

6. The raised beam-tube-slab combined hybrid tower foundation structure according to claim 1, characterized in that, The prestressed steel strand assembly is arranged in a circumferentially uniform manner within the connecting pier, with the lower tensioning point positioned above the natural fill.

7. The raised beam-tube-slab combined hybrid tower foundation structure according to claim 1, characterized in that, The prestressed anchor bolt assembly is pre-embedded in the bottom of the cylindrical body. When it is fixed at the top of the connecting pier, an anchor plate is configured. The number and spacing of the anchor bolts are determined according to the structural stress calculation.

8. A raised beam-tube-slab combined hybrid tower foundation structure according to any one of claims 1-7, characterized in that, The construction process for the mixed-structure tower foundation is as follows: First, construct the cylindrical shell and pre-embedded prestressed anchor bolt assemblies, then pour the cylindrical shell and buttress columns; precast raised precast beams and cure them; place the raised precast beams in position; tie the connecting pile cap reinforcement, reserve ducts and perform preliminary positioning; pour the connecting pile cap concrete in place; after the connecting pile cap concrete reaches the design strength, anchor the prestressed anchor bolt assemblies; finally, complete the connection between the upper tower body and the prestressed steel strand assemblies, realizing the overall construction of the mixed tower foundation, and subsequent maintenance can be carried out through the doorway on the cylindrical shell, ensuring the long-term reliable operation of the structure.

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