Foundation construction method for a fan
By using a combination structure of hexagonal honeycomb geocells and plain concrete cushion layers in the wind turbine foundation, the problems of long construction period and high cost were solved, achieving efficient and environmentally friendly foundation treatment and improving the stability and construction efficiency of the foundation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA HYDROELECTRIC ENGINEERING CONSULTING GROUP CHENGDU RESEARCH HYDROELECTRIC INVESTIGATION DESIGN AND INSTITUTE
- Filing Date
- 2024-05-13
- Publication Date
- 2026-07-24
AI Technical Summary
In existing technologies, wind turbine foundations have long construction cycles and high costs in soft soil treatment, and cause significant environmental damage, making it difficult to meet construction efficiency and environmental protection requirements.
The construction method of combining geocell layers with plain concrete cushion layers involves laying hexagonal honeycomb geocells at the bottom of the foundation pit, filling them with crushed stone or on-site soil, compacting them with static and vibratory rollers, and then pouring concrete to form a composite structure. This method utilizes the high strength and drainage performance of HDPE materials to reduce construction difficulty and cost.
It shortens the construction period, reduces costs, improves the stability and service life of the foundation, meets the requirements of green and environmentally friendly construction, and reduces the impact on the environment.
Smart Images
Figure CN118326937B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to building construction technology, and more particularly to a method for constructing a wind turbine foundation. Background Technology
[0002] The loads transmitted from the wind turbine tower to the foundation are complex, requiring the foundation and subgrade to withstand significant pressure, bending moments, and horizontal forces. Furthermore, wind turbines are highly sensitive to foundation deformation and displacement, necessitating sufficient subgrade rigidity to prevent uneven settlement under eccentric loading and cyclic dynamic loads. However, the subgrades in central and southern my country are primarily composed of soft soil layers with poor mechanical properties, such as silt and loess, making these conditions unfavorable for the stability and safety of wind turbine foundations.
[0003] In existing technologies, a prestressed pipe pile group is generally installed at the bottom of the reinforced concrete extended foundation, and a cushion layer is installed between the two to form a separate structural connection and a composite load-bearing structure, thereby strengthening the bearing sand layer of the wind turbine extended foundation through composite foundation treatment; or a plain soil cushion layer is installed at the bottom of the foundation pit and the foundation pit slope, a lime-soil cushion layer is installed on the plain soil cushion layer, and the wind turbine foundation is installed on the lime-soil cushion layer. Backfill soil is installed around the foundation in the foundation pit between the foundation pit and the foundation pit slope and the wind turbine foundation, and a drainage area is set on the backfill soil around the foundation in the foundation pit.
[0004] When using the traditional foundation treatment methods described above to treat the weak foundation of wind turbines, the treatment scale is large and the cost is high when deep treatment is carried out on the weak foundation. Even when using the above methods to treat the weak foundation of wind turbines, a large amount of unsuitable soil needs to be excavated and transported to a spoil disposal site, and then backfilled with soil, sand, gravel, and crushed stone. Moreover, the wind farm is often located in a remote area, which not only involves a large amount of transportation and high costs, but also takes a long time to construct and causes significant environmental damage. Summary of the Invention
[0005] To overcome the shortcomings of existing technologies, such as long construction periods and high losses, the technical problem to be solved by this invention is: how to improve construction efficiency and reduce costs.
[0006] The technical solution adopted by this invention to solve its technical problem is:
[0007] A method for constructing the foundation of a wind turbine, characterized by the following steps:
[0008] S1: Excavation of the foundation pit. The foundation pit is excavated according to the wind turbine foundation excavation drawing. After excavation, the bottom of the pit is cleaned, leveled and compacted. The foundation pit is located in a reasonable position to determine the foundation location, which will facilitate subsequent construction.
[0009] S2: Lay geocells. Lay geocells at the bottom of the excavated pit. The height of the geocells is determined based on the depth of the replacement of the weak soil layer and the bearing capacity of the underlying soil layer. The geocells are placed at the bottom of the foundation pit to form a reinforcement layer for the foundation at the bottom of the pit.
[0010] S3: Filler material is evenly spread into the geocell. The material can be crushed stone or soil from the construction site. Using nearby materials to fill the geocell reduces the workload and provides sufficient filling strength.
[0011] S4: Compaction, which uses a combination of static rolling and vibratory rolling to compact the material filled into the geocell.
[0012] S5: Pouring, installing formwork on the surface of the geocell layer, injecting concrete into the geocell, using a vibrator to compact the concrete, and performing smoothing, polishing or other surface treatment operations.
[0013] Furthermore, the aforementioned geocell is a hexagonal honeycomb-shaped cell, which specifically defines the shape of the geocell, and the hexagonal honeycomb structure has the characteristics of high strength and compact structure.
[0014] Furthermore, the sidewalls of the aforementioned geocells are provided with multiple through holes, which improve the drainage performance of the geocells.
[0015] Furthermore, the aforementioned geocell comprises multiple cells. Each cell includes an interconnected regular hexagonal cell and a concave hexagonal cell. The concave hexagonal cell has two opposing concave vertices and four convex vertices, with the two concave vertices having the same angle and being centrally symmetrical about the concave hexagonal cell. The two side plates of the concave hexagonal cell, located on either side of the concave vertices, are parallel and of equal length. Each concave vertices of the concave hexagonal cell is opposite to any vertices of the regular hexagon and connected by a connecting column. Through the hybrid connection design of regular hexagons and concave hexagons, the Poisson's ratio (positive, zero, and negative) can be adjusted by changing the geometric parameters. Cells are connected by rods, and tensile or compressive loads are transferred between cells through the connections, thereby generating deformation. The hybrid honeycomb cell design enables the structure to exhibit isoplastic and antiplastic behavior in different regions and provides higher stiffness.
[0016] Furthermore, the geocells mentioned above are made of HDPE material, which can withstand large loads and stresses, ensuring the stability and safety of the foundation structure; they are also lighter than traditional materials, making them easier to transport, handle and install, thus reducing construction difficulty and cost.
[0017] Furthermore, in step S2, the longitudinal and transverse intersections of the geocells are connected using clips or U-shaped nails, and fixed with a self-anchoring reinforcement structure to ensure the connection stability between the geocell panels.
[0018] Furthermore, in step S3, the particle size of the crushed stone is less than 30mm and the moisture content of the soil is less than 8%, which limits the particle size of the crushed stone and the moisture content of the soil, thereby improving the strength of the geogrid after filling.
[0019] Furthermore, in step S3, the loose-lay coefficient is determined according to different materials, and the height of the filler protective layer is reserved. The height of the filler above the cell is determined comprehensively to ensure the optimal material filling amount and the strength after filling.
[0020] Furthermore, step S4 specifically involves: using a static roller to fix the material in the geocell, applying static pressure 2-3 times to ensure the geocell is completely covered by the material; then using a vibratory roller to further compact the fill material. Throughout the process, the stress on the geocell must be observed at all times to prevent excessive compaction from damaging the geocell; after the geocell is laid, the compaction degree is measured. If it does not meet the compaction degree requirements, the above compaction operation is repeated. This process specifically limits the details of the compaction operation to prevent excessive pressure during compaction from damaging the geocell, and the compaction degree test ensures that the final compaction degree meets the requirements.
[0021] Furthermore, step S5 also includes curing the newly poured concrete after completing the surface treatment operation, and covering the concrete surface with a wet cloth or spraying water to properly cure the newly poured concrete to ensure its strength gradually increases.
[0022] The beneficial effects of this invention are:
[0023] This invention relies on actual site conditions, using locally sourced materials to lay the geocell layer. The finished geocells are transported to the site, resulting in a short construction period and controllable foundation treatment quality. During construction, the geocells can be stretched into a mesh and filled with loose materials such as soil, gravel, and concrete to form a structure with strong lateral confinement and high rigidity. Simultaneously, the plain concrete layer also possesses a certain degree of resistance to environmental erosion. The composite structural layer formed by the combination of the geocell layer and the plain concrete layer can improve the overall service life of the structure. Attached Figure Description
[0024] Figure 1 This is a flowchart of the construction method of the present invention;
[0025] Figure 2 This is a schematic diagram of the foundation pit structure of the present invention;
[0026] Figure 3 This is a schematic diagram of the geocell structure of the present invention;
[0027] Figure 4 This is a schematic diagram of the geocell cell connection structure of the present invention. Figure 1 ;
[0028] Figure 5This is a schematic diagram of the geocell cell connection structure of the present invention. Figure 2 ;
[0029] The markings in the diagram are: 1-Foundation pit, 2-Geocell, 3-Regular hexagonal cell, 4-Concave hexagonal cell, 5-Connecting rod. Detailed Implementation
[0030] The invention will be further described below with reference to the accompanying drawings.
[0031] This application proposes a method for constructing a wind turbine foundation, such as... Figure 1 As shown, it includes the following steps:
[0032] S1: Excavation of foundation pit 1, such as Figure 2 As shown, the foundation pit 1 is excavated according to the wind turbine foundation excavation drawing. After excavation, the bottom of the pit is cleaned, leveled, and compacted. Specifically, the foundation pit 1 is excavated to the base elevation of the wind turbine extended foundation. If the geocell 2 is directly arranged on the surface of the foundation pit 1, it will have a certain impact on the normal performance of the geocell 2. Therefore, the foundation pit 1 needs to be treated first. The bottom of the pit is cleaned, the site is leveled, and compacted to ensure that it meets the compaction and flatness requirements of the specifications.
[0033] S2: Laying Geocell 2. Geocell 2 is laid at the bottom of the excavated pit. The height of Geocell 2 is determined based on the depth of the replacement of the weak soil layer and the bearing capacity of the underlying soil layer. Specifically, on the accepted foundation pit 1, geocell 2 is unfolded, straightened, and laid flat against the foundation pit 1. Intersections in the longitudinal and transverse directions are connected using clips or U-shaped nails, and fixed using a self-anchoring reinforcement method to ensure interconnection between the geocell panels and maintain overall stress balance. The use of geocell 2 helps reduce soil settlement and control the slope, providing a relatively stable wind turbine foundation support, reducing the risk of foundation deformation, and extending the foundation's service life.
[0034] S3: Fill material. The material is evenly spread into the geocell 2. The material is crushed stone or soil from the construction site. The slab is spread using a loader or backhoe in conjunction with manual labor. The mechanical backfilling is carried out on the fixed geocell 2. During the backfilling process, the accumulated fill material is evenly spread into the geocell 2 at any time.
[0035] The filling material should be crushed stone or soil from the construction site. Crushed stone with a maximum particle size of 30mm or less and few impurities should be selected, or locally sourced soil with low moisture content and few impurities should be used. The principle for selecting filling material is to ensure quality control while fully considering and utilizing on-site resources. This approach not only saves construction costs and shortens the construction period but also has a smaller environmental impact, aligning with the green theme of new energy wind power generation. Adopting on-site material sourcing and resource utilization construction methods conforms to green environmental protection concepts, reduces environmental impact, and meets the requirements of sustainable development.
[0036] In addition, during construction, the loose-lay coefficient should be determined according to different fill materials, and the height of the fill material protective layer should be reserved. The height of the fill material above the cell should be determined comprehensively.
[0037] S4: Compaction. The material filled into geocell 2 is compacted using a combination of static rolling and vibratory rolling. Specifically, static rolling is used to fix the filler in geocell 2, and static rolling is performed 2-3 times to ensure that geocell 2 is completely covered by the filler. Then, vibratory rolling is used to further compact the filler. Throughout the process, the stress on geocell 2 needs to be observed at all times to prevent excessive rolling from damaging geocell 2. After the geocells are laid, the degree of compaction needs to be measured to meet the design requirements.
[0038] S5: Pouring. Install formwork on the surface of the second geocell layer to ensure a regular foundation shape during concrete pouring. Pour concrete evenly over the second geocell layer, controlling the pouring speed and slump to prevent air bubbles and cracks. Inject concrete into the second geocell layer and compact it using a vibrator. Perform smoothing, polishing, or other surface treatments. The combination of the second geocell layer and the plain concrete cushion layer utilizes on-site material sourcing, avoiding the excavation and transportation of large amounts of unsuitable soil, thus saving construction costs. Furthermore, compared to traditional foundation treatment methods, this combination shortens the construction cycle and improves construction efficiency.
[0039] In addition, newly poured concrete should be properly cured to ensure its strength gradually increases. During the curing period, it is necessary to prevent the concrete surface from cracking, which is usually done by covering it with a damp cloth or spraying water.
[0040] It should be noted that the geocell 2 material mentioned above is HDPE. HDPE has excellent corrosion resistance, can resist the erosion of soil, water and chemicals for a long time, and maintain stable performance. It has high tensile and compressive strength, can withstand large loads and stresses, and ensure the stability and safety of the foundation structure. Compared with traditional materials, it is lighter, which is convenient for transportation, handling and installation, reducing construction difficulty and cost. It has good aging resistance and long-term stability, with a long service life and can operate continuously for many years. It has high flexibility and bending capacity, which can adapt to the deformation and torsion of the foundation and maintain overall stability. It is manufactured with environmentally friendly materials, is non-toxic and harmless, will not cause pollution to the environment, and meets the requirements of sustainable development.
[0041] Furthermore, regarding the shape of geocell 2, traditional geocell 2 cells are mostly honeycomb or quadrilateral. Therefore, the cells composed of these single cells are Poisson's ratio materials. As the foundation load increases, the cells are subjected to tensile forces, leading to shrinkage along the thickness direction. This, in turn, causes shearing of the fill material at the reinforcement-soil interface, increasing the risk of reinforcement pull-out. To improve the expansion or stretching phenomena of the cells under tension, eliminate axial outward deformation of the structure, enhance the interaction between reinforcement and fill material, and increase the load-bearing capacity of geocell 2, such as... Figure 3 As shown, the geocell 2 is a hexagonal honeycomb-shaped cell.
[0042] Furthermore, to enhance the overall drainage performance of the structure, multiple through holes are provided on the sidewalls of the geocell 2. The perforated geocell 2 layer has good drainage performance, enabling it to quickly remove moisture from the foundation area and prevent water accumulation. The plain concrete cushion layer provides a relatively dense surface, which helps to further reduce water penetration.
[0043] In a preferred embodiment, such as Figure 3 , Figure 4 As shown, the geocell 2 includes multiple cells. Each cell includes a regular hexagonal cell 3 and a concave hexagonal cell 4 connected to each other. The concave hexagonal cell 4 has two opposite concave apex angles and four convex angles. The two concave apex angles are the same and are based on the central symmetry of the concave hexagonal cell 4. The two side plates of the concave hexagonal cell 4 distributed on both sides of the concave apex angle are parallel and of equal length. Any concave apex angle of the concave hexagonal cell 4 is opposite to any apex angle of the regular hexagon and connected by a connecting column 5. This hybrid honeycomb structure can achieve an adjustable Poisson's ratio (positive, zero, and negative) by changing the geometric parameters. The cells are connected by rods. Tensile or compressive loads are transmitted between the cells through the connection points, thereby generating deformation. Hybrid hexagonal geocells enable the structure to exhibit both isoplastic and antiplastic behavior in different regions, while providing higher stiffness. The two-layer hybrid hexagonal geocell system prevents expansion or stretching of the cells under tension, eliminates axial outward deformation, improves the interaction between reinforcement and filler, increases the load-bearing capacity of the geocell, and enhances the stability of the two-layer geocell system. It provides a larger load-bearing area, which helps to evenly distribute the load on the wind turbine foundation and reduces stress concentration problems caused by insufficient local load-bearing area. The plain concrete cushion layer provides a solid surface, enhancing overall stability. Furthermore, hybrid hexagonal geocells offer more adjustable design parameters than traditional hexagonal geocells, greatly expanding the design space of the geocell unit cell, such as… Figure 5 As shown, t represents the cell wall thickness, l1, l2, l3, and l4 are the side lengths of a single cell, and θ1 and θ2 represent the tilt angles. The geometry of the hybrid hexagon needs to satisfy the following relationship:
[0044] l1cosθ1=l2 sinθ2
[0045] In summary, the combination of hybrid honeycomb geocells and plain concrete cushion layer in the technical solution proposed in this invention optimizes the performance of the wind turbine foundation, improves the stability and bearing capacity of the foundation, reduces construction costs, saves construction time, and meets the requirements of environmental protection and sustainable development.
Claims
1. A method for constructing the foundation of a wind turbine, characterized in that, Includes the following steps: S1: Excavation of the foundation pit (1): Excavate the foundation pit (1) according to the wind turbine foundation excavation drawing. After excavation, clean the bottom of the pit, level and compact the bottom of the pit. S2: Lay geocells (2). Lay geocells (2) at the bottom of the excavated pit. The height of the geocells (2) is determined according to the depth of the replacement of the weak soil layer and the bearing capacity of the underlying soil layer. The geocells (2) are hexagonal honeycomb cells. The geocells (2) include multiple cells. Each cell includes a regular hexagonal cell (3) and a concave hexagonal cell (4) connected to each other. The concave hexagonal cell (4) has two opposite concave apex angles and four convex angles. The two concave apex angles are the same and based on the central symmetry of the concave hexagonal cell (4). The two side plates of the concave hexagonal cell (4) distributed on both sides of the concave apex angle are parallel and have equal lengths. Any concave apex angle of the concave hexagonal cell (4) is opposite to any apex angle of the regular hexagon and connected by a connecting column (5). S3: Filler, spread the material evenly into the geocell (2), the material is crushed stone soil or soil from the construction site; S4: Compaction, using a combination of static rolling and vibratory rolling to compact the material filled into the geocell (2); S5: Pouring, installing templates on the surface of the geocell (2) layer, injecting concrete into the geocell (2), using a vibrator to compact the concrete, and performing surface treatment operations.
2. The wind turbine foundation construction method according to claim 1, characterized in that, The side wall of the geocell (2) has multiple through holes.
3. The wind turbine foundation construction method according to claim 1, characterized in that, The geocell (2) is made of HDPE material.
4. The wind turbine foundation construction method according to claim 1, characterized in that, In step S2, the geocells (2) are connected at the intersection of longitudinal and transverse directions using buckles or U-shaped nails and fixed with a self-anchoring reinforcement structure.
5. The wind turbine foundation construction method according to claim 1, characterized in that, In step S3, the crushed stone particle size is less than 30 mm, and the soil moisture content is less than 8%.
6. The wind turbine foundation construction method according to claim 1, characterized in that, In step S3, the loose-lay coefficient is determined according to different materials, and the height of the filler protective layer is reserved. The height of the filler above the cell is determined comprehensively.
7. The wind turbine foundation construction method according to claim 1, characterized in that, Step S4 includes: using a static roller to fix the material in the geocell (2), and statically pressing 2-3 times to ensure that the geocell (2) is completely covered by the material; then using a vibratory roller to further compact the filler. Throughout the process, the stress on the geocell (2) needs to be observed at all times; after the geocell is laid, the compaction degree is measured. If it does not meet the compaction degree requirements, the above compaction operation is repeated.
8. The method for constructing the foundation of a wind turbine according to claim 1, characterized in that, Step S5 also includes curing the newly poured concrete after the surface treatment operation is completed, and covering the concrete surface with a damp cloth or spraying water.