A cured soft soil bearing layer FRP-steel honeycomb web photovoltaic pile foundation and a construction method thereof

Abstract

This invention relates to the field of soft soil pile foundation engineering technology, specifically to a photovoltaic pile foundation with FRP-steel honeycomb web and a construction method for solidifying a soft soil bearing layer. The pile foundation includes an FRP-steel honeycomb web photovoltaic pile foundation and a solidified soft soil bearing layer. The bottom of the FRP-steel honeycomb web photovoltaic pile foundation is located in the solidified soft soil bearing layer, and its top is located above the ground. The FRP-steel honeycomb web photovoltaic pile foundation includes a core mold, concrete, and a fiber-wound layer. The core mold includes a cross-shaped steel column and an FRP sleeve. Through holes are provided on the web of the cross-shaped steel column and on the two straight plates of the FRP sleeve. The FRP sleeve is fixed between two adjacent webs of the cross-shaped steel column. The number and position of the through holes on each straight plate of the FRP sleeve correspond to the number of through holes on the web of the corresponding cross-shaped steel column. Concrete is poured inside the FRP sleeve, and the fiber-wound layer is located on the outside of the core mold. This invention reduces the weight and cost of the photovoltaic pile foundation and improves its durability and stability in soft soil areas.

Description

Technical Field

[0001] This invention relates to the field of soft soil pile foundation engineering technology, specifically to a photovoltaic pile foundation with FRP-steel honeycomb web and a construction method for solidifying soft soil bearing layer. Background Technology

[0002] Soft soil is widely distributed in my country, mainly concentrated in coastal areas, the middle and lower reaches of rivers, around lakes, and in mountainous valleys and plains. It often has engineering characteristics such as high compressibility, low strength, rheological properties, heterogeneity, and poor permeability, which makes the engineering conditions based on soft soil very complex. In particular, the corrosive effects of the saline-alkali environment in soft soil areas such as tidal flats in coastal areas have a great impact on engineering construction in soft soil areas.

[0003] Because photovoltaic (PV) power generation requires a large amount of land, PV power plants are currently mainly located in soft soil areas such as deserts, coastal areas, and riverbanks. The foundations of PV power plants already built in soft soil areas primarily use PHC (Polymer Concrete Cemented Carbide) pipe piles. While PHC pipe piles have advantages such as mature production technology and low cost, their concrete material results in significant weight, making transportation and construction inconvenient. In soft soil areas, they also suffer from severe settlement and poor stability, greatly impacting long-term operation. Therefore, lightweight foundations are a crucial trend in the development of PV foundations in soft soil. Furthermore, soft soil areas are mostly located in coastal regions, such as tidal flats, where PV pile foundations are susceptible to seawater erosion. The commonly used PHC pipe piles, in particular, have poor corrosion resistance and are more easily corroded, significantly reducing their service life. Therefore, the corrosion resistance of PV pile foundations is also a very important issue. Summary of the Invention

[0004] To address the problems in the background technology, reduce the possibility of settlement of photovoltaic pile foundations in soft soil areas, and improve the stability and corrosion resistance of photovoltaic pile foundations, this invention proposes a photovoltaic pile foundation with FRP-steel honeycomb web for solidifying soft soil bearing layer and its construction method. The technical solution is as follows:

[0005] A photovoltaic pile foundation with FRP-steel honeycomb web and solidified soft soil bearing layer includes a soft soil area filled with soft soil solidification material and an FRP-steel honeycomb web photovoltaic pile foundation. The soft soil area is a solidified soft soil bearing layer. The bottom of the FRP-steel honeycomb web photovoltaic pile foundation is buried in the solidified soft soil bearing layer, and the top of the FRP-steel honeycomb web photovoltaic pile foundation extends to above the ground.

[0006] The FRP-steel honeycomb web photovoltaic pile foundation includes a cylindrical core mold, concrete, and a wound fiber layer. The core mold includes a cross-shaped steel column and four FRP sleeves. The web of the cross-shaped steel column has honeycomb-shaped through holes. The FRP sleeves are quarter-circular arc-shaped, and both straight plates of the FRP sleeves have honeycomb-shaped through holes. The four FRP sleeves are respectively fixed between two adjacent webs of the cross-shaped steel column. The number and position of the through holes on the straight plate of each FRP sleeve correspond to the number of through holes on the web of the corresponding cross-shaped steel column. The concrete is poured inside the FRP sleeves, and the wound fiber layer is located on the outside of the core mold.

[0007] Preferably, the solidified soft soil bearing layer is located within a range of 2 / 3 of the pile length upwards and 1 / 3 of the pile length downwards from the bottom of the FRP-steel honeycomb web photovoltaic pile foundation.

[0008] Preferably, the soft soil solidification material includes granulated blast furnace slag, fly ash, carbide slag, phosphogypsum, straw fiber, alkali activator, and water; the percentage of each material is as follows: granulated blast furnace slag 15%~20%, fly ash 8%~12%, carbide slag 3%~6%, phosphogypsum 5%~10%, straw fiber 0.8%~1.2%, alkali activator 0.5%~1%, and water 10%~15%.

[0009] Preferably, the preparation method of the FRP-steel honeycomb web photovoltaic pile foundation is as follows:

[0010] Precast cross-shaped steel columns and FRP sleeves are provided. An FRP sleeve is provided between two adjacent webs of each cross-shaped steel column, and the through holes on the straight edge plate of the FRP sleeve correspond one-to-one with the through holes on the web of the cross-shaped steel column.

[0011] The FRP sleeve and the cross-shaped steel column are connected by curing with epoxy resin, and the two are fixed together to form a core mold;

[0012] A fiber composite material is wound around the outer surface of the mandrel to form a wound fiber layer on the outer side of the mandrel.

[0013] Preferably, the process for preparing the wound fiber layer is as follows: the fiber composite material is directly impregnated with resin under tension, and the impregnated fiber composite material is continuously wound onto the outer surface of the mandrel according to the wet winding molding process. The number of winding layers is at least four, and the winding angle of each layer of fiber composite material is 75 degrees, 60 degrees, 45 degrees and 30 degrees from the inside to the outside. After the winding is completed, the wound fiber layer is obtained by heating and curing.

[0014] The fibers in the fiber composite material are any one of carbon fiber, glass fiber, basalt fiber, and hybrid fiber.

[0015] Preferably, the FRP sleeve manufacturing process is as follows: first, fiber yarn is prepared from fiber reinforced composite material, then the fiber yarn is impregnated with resin, and finally the FRP sleeve is obtained by integral pultrusion molding process.

[0016] The impregnation resin is any one of unsaturated resin, vinyl resin, epoxy resin, and phenolic resin, and the fiber material in the fiber-reinforced composite material is any one of carbon fiber, glass fiber, basalt fiber, and hybrid fiber.

[0017] A construction method for a photovoltaic pile foundation with FRP-steel honeycomb web in a solidified soft soil bearing layer, implemented based on the aforementioned photovoltaic pile foundation with FRP-steel honeycomb web in a solidified soft soil bearing layer, includes the following steps:

[0018] S1. Determine the pile foundation depth, mark the pile positions, clear away debris, level and initially compact the land, and pave the construction site.

[0019] S2. Investigate geological conditions, determine construction plans, and prepare soft soil consolidation materials;

[0020] S3. Determine the soft soil area to be grouted according to the construction plan, inject soft soil solidification material into the soft soil within the required range using grouting equipment, and cure for 7 to 28 days to form a solidified soft soil bearing layer. After curing, test the soil strength to ensure that the unconfined compressive strength of the solidified soft soil bearing layer is not less than 2.5 MPa.

[0021] S4. Before the soft soil bearing layer reaches the required strength, the FRP-steel honeycomb web photovoltaic pile foundation shall be constructed using the driving method or static pressure method.

[0022] After the construction of S5 and FRP-steel honeycomb web photovoltaic pile foundation is completed, a clamp is fitted on the top of the pile foundation and the clamp is tightened in the required position;

[0023] S6. Install photovoltaic brackets and photovoltaic panels on the clamps to complete the pile foundation construction.

[0024] Preferably, the method for preparing the soft soil solidification material in step S2 is as follows:

[0025] A1. Based on the geological survey results and construction requirements, the proportions of granulated blast furnace slag, carbide slag, phosphogypsum, straw fiber, alkali activator, and water are adjusted to determine the proportions of each material to meet construction requirements.

[0026] A2. Granulated blast furnace slag, carbide slag, phosphogypsum, straw fiber, and water are added to a mixer according to the specified ratio and mixed to obtain a fluidized mixture.

[0027] A3. After the plasticizing mixture is stirred evenly, add the alkali activator into the mixer and continue stirring. After the plasticizing mixture and the alkali activator are stirred evenly, the soft soil solidification material is obtained.

[0028] Preferably, the specific construction method for solidifying the soft soil bearing layer in step S3 is as follows:

[0029] B1. Arrange the grouting hole positions according to the soft soil conditions and the marked pile positions. Drill holes at the grouting hole positions using a drilling rig or hand drill to the required depth to obtain the grouting holes, and explore the geological conditions.

[0030] B2. Grouting is carried out using grouting equipment, which includes grouting nozzles and grouting pumps. The grouting nozzles have grouting through holes on the pipe wall near their bottom ends. During grouting, the bottom end of the grouting nozzles is inserted into the grouting holes, and the top end of the grouting nozzles is connected to the grouting pumps.

[0031] B3. The soft soil stabilization material is continuously injected into the soft soil in sections using a grouting pump and grouting jet pipe;

[0032] B4. After grouting is completed, slowly pull out the grouting nozzle and seal the grouting hole.

[0033] B5. Carry out maintenance and monitoring to ensure that the solidification effect of soft soil meets the requirements.

[0034] Preferably, the construction process of the FRP-steel honeycomb web photovoltaic pile foundation in step S4 is as follows:

[0035] When using the driving method, first use a pile driving device with low energy, low stroke or empty hammer to hammer the pile foundation. After confirming that there is no abnormality in the direction of pile penetration, continue normal hammering. After the pile bottom reaches the solidified soft soil bearing layer, ensure that the pile top is still 1.5m above the ground surface. After the pile foundation construction is completed, conduct strength and stability tests on each pile foundation.

[0036] The beneficial effects of this invention are as follows:

[0037] (1) Before the construction of photovoltaic pile foundation, the present invention first uses grouting process to solidify the soft soil bearing layer, thereby improving the mechanical properties of the foundation soil around the pile foundation, thereby improving the stability of the pile foundation and reducing settlement.

[0038] (2) This invention uses industrial waste and straw fiber to prepare soft soil solidification material, which improves the strength and uniformity of soft soil while achieving the purpose of waste utilization and low carbon environmental protection.

[0039] (3) The FRP-steel honeycomb web photovoltaic pile foundation of the present invention is composed of a combination of steel structure, FRP material, concrete, and composite fiber, and adopts an innovative structure: the FRP sleeve is connected to the cross-shaped steel column, and the two form an integral cylindrical core mold. Fiber composite material is wound around the outside of the core mold, and the through holes of the FRP sleeve and the cross-shaped steel column correspond to each other, which can ensure that the concrete inside the four FRP sleeves is connected. The present invention greatly reduces the weight of the pile foundation, while improving the toughness, strength and corrosion resistance of the photovoltaic pile foundation, thereby improving the efficiency of the construction and transportation stages, and reducing long-term operating costs.

[0040] (4) This invention addresses the issues of photovoltaic pile foundation structure design and bearing layer solidification. The former provides a high-toughness, low-weight, high-strength, and corrosion-resistant FRP-steel honeycomb web photovoltaic pile foundation structure, while the latter provides a method to improve the properties of soft soil by incorporating soft soil solidification materials into the bearing layer of the pile foundation. This invention solves the problems of easy settlement and poor durability of photovoltaic pile foundations in soft soil areas. Furthermore, by using FRP materials to make internal sleeves, compared with the traditional mainstream PHC pipe piles, this invention can significantly reduce the weight while improving the strength and corrosion resistance of the pile foundation, achieving lightweight equipment, reducing construction difficulty, improving construction efficiency, and reducing subsequent maintenance costs. Attached Figure Description

[0041] Figure 1 This is a schematic elevation view of the overall structure of the present invention;

[0042] Figure 2 This is a schematic diagram of the overall structure of the FRP-steel honeycomb web photovoltaic pile foundation of the present invention;

[0043] Figure 3 This is a schematic diagram of the FRP sleeve structure of the present invention;

[0044] Figure 4 This is a schematic diagram of the cross-shaped steel column structure of the present invention;

[0045] Figure 5 This is a schematic diagram of the cross-sectional structure of the FRP-steel honeycomb web photovoltaic pile foundation of the present invention;

[0046] Figure 6 This is a flowchart of the construction method of the present invention.

[0047] The following are labeled in the diagram: 1. Grouting pump; 2. Grouting nozzle; 3. Solidified soft soil bearing layer; 4. FRP-steel honeycomb web photovoltaic pile foundation; 5. Hoop; 6. Photovoltaic support; 7. Photovoltaic panel; 8. Wound fiber layer; 9. FRP sleeve; 10. Concrete; 11. Cross-shaped steel column. Detailed Implementation

[0048] To make the present invention clearer and more understandable, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the given embodiments are only one of the implementation methods and do not represent all embodiments.

[0049] In this article, terms such as "inner," "outer," "upper," and "lower" are established based on the positional relationships shown in the attached drawings. Depending on the attached drawings, the corresponding positional relationships may also change. Therefore, they should not be interpreted as an absolute limitation on the scope of protection.

[0050] Combined with appendix Figure 1 - Appendix Figure 5 A photovoltaic pile foundation with FRP-steel honeycomb web plate and solidified soft soil bearing layer includes a soft soil area filled with soft soil solidification material and an FRP-steel honeycomb web plate photovoltaic pile foundation 4. The soft soil area is a solidified soft soil bearing layer 3. The bottom of the FRP-steel honeycomb web plate photovoltaic pile foundation 4 is buried in the solidified soft soil bearing layer 3. The solidified soft soil bearing layer 3 is located within a range of 2 / 3 of the pile length upward and 1 / 3 of the pile length downward from the bottom of the FRP-steel honeycomb web plate photovoltaic pile foundation 4. The top of the FRP-steel honeycomb web plate photovoltaic pile foundation 4 extends to above the ground.

[0051] The FRP-steel honeycomb web photovoltaic pile foundation 4 includes a cylindrical core mold, concrete 10, and a wound fiber layer 8. The core mold includes a cross-shaped steel column 11 and four FRP sleeves 9. The web of the cross-shaped steel column 11 is provided with honeycomb-shaped through holes. The FRP sleeves 9 are in the shape of a quarter circle. Both straight plates of the FRP sleeves 9 are provided with honeycomb-shaped through holes. The four FRP sleeves 9 are respectively fixed between two adjacent webs of the cross-shaped steel column 11. The number and position of the through holes on the straight plate of each FRP sleeve 9 correspond to the number of through holes on the web of the corresponding cross-shaped steel column 11. The concrete 10 is poured into the FRP sleeves 9. The wound fiber layer 8 is located on the outside of the core mold.

[0052] Specifically, the cross-shaped steel column 11 is made of Q235B steel and the concrete 10 is C30 concrete.

[0053] Specifically, the soft soil stabilization material includes granulated blast furnace slag, fly ash, carbide slag, phosphogypsum, straw fiber, alkali activator, and water; the percentage of each material is as follows: granulated blast furnace slag 15%~20%, fly ash 8%~12%, carbide slag 3%~6%, phosphogypsum 5%~10%, straw fiber 0.8%~1.2%, alkali activator 0.5%~1%, and water 10%~15%.

[0054] Specifically, the preparation method of the FRP-steel honeycomb web photovoltaic pile foundation 4 is as follows:

[0055] Prefabricated cross-shaped steel columns 11 and FRP sleeves 9, with FRP sleeves 9 provided between two adjacent webs of each cross-shaped steel column 11, and the through holes on the straight edge plate of the FRP sleeve 9 corresponding one-to-one with the through holes on the web of the cross-shaped steel column 11.

[0056] The FRP sleeve 9 and the cross-shaped steel column 11 are connected by epoxy resin curing and fixed to form a core mold;

[0057] A fiber composite material is wound around the outer surface of the mandrel to form a wound fiber layer 8 on the outer side of the mandrel.

[0058] Specifically, the preparation process of the wound fiber layer 8 is as follows: the fiber composite material is directly impregnated with resin under tension, and the impregnated fiber composite material is continuously wound onto the outer surface of the mandrel using a wet winding molding process. The number of winding layers is at least four, and the winding angle of each layer of fiber composite material is 75 degrees, 60 degrees, 45 degrees, and 30 degrees from the inside to the outside. After winding, the fiber composite material is heated and cured to obtain the wound fiber layer 8 set on the outside of the mandrel. When the number of winding layers needs to exceed four, the winding angle of each layer of fiber composite material can be cycled according to 75 degrees, 60 degrees, 45 degrees, and 30 degrees. The winding angle is the angle between the fiber composite material and the axis of the mandrel. When the winding angle is 30 degrees, the winding direction of the fiber composite material is closer to the axis of the mandrel, which is beneficial to improving the axial strength of the mandrel. When the winding angle is 75 degrees, the winding direction of the fiber composite material is closer to the radial direction of the mandrel, which is beneficial to improving the radial strength of the mandrel.

[0059] The fibers in the fiber composite material are any one of carbon fiber, glass fiber, basalt fiber, and hybrid fiber.

[0060] Specifically, the manufacturing process of the FRP sleeve 9 is as follows: first, fiber yarn is prepared from fiber reinforced composite material, then the fiber yarn is impregnated with resin, and finally the FRP sleeve 9 is obtained by integral pultrusion molding process.

[0061] The impregnation resin is any one of unsaturated resin, vinyl resin, epoxy resin, and phenolic resin, and the fiber material in the fiber-reinforced composite material is any one of carbon fiber, glass fiber, basalt fiber, and hybrid fiber.

[0062] Combined with appendix Figure 6 A construction method for a photovoltaic pile foundation with FRP-steel honeycomb web in a solidified soft soil bearing layer, implemented based on the aforementioned photovoltaic pile foundation with FRP-steel honeycomb web in a solidified soft soil bearing layer, includes the following steps:

[0063] S1. Determine the pile foundation depth, mark the pile positions, clear debris, level and initially compact the land, and pave the construction site; specifically, a total station, GPS and other equipment can be used for accurate pile position marking.

[0064] S2. Investigate geological conditions, determine construction plans, and prepare soft soil consolidation materials;

[0065] The preparation method of the soft soil stabilization material is as follows:

[0066] A1. Based on the geological survey results and construction requirements, the proportions of granulated blast furnace slag, carbide slag, phosphogypsum, straw fiber, alkali activator, and water are adjusted to determine the proportions of each material to meet construction requirements.

[0067] Specifically, the preferred material composition is: 15% granulated blast furnace slag, 10% fly ash, 5% calcium carbide slag, 8% phosphogypsum, 1% straw fiber, 0.6% alkali activator, and 10% water;

[0068] A2. Granulated blast furnace slag, carbide slag, phosphogypsum, straw fiber, and water are added to a mixer according to the specified ratio and mixed to obtain a fluidized mixture.

[0069] A3. After the fluidized plastic mixture is stirred evenly, add the alkali activator into the mixer and continue stirring. After the fluidized plastic mixture and the alkali activator are stirred evenly, the soft soil solidification material is obtained.

[0070] Specifically, the alkali activator is composed of 25% silica fume, 40% sodium hydroxide, 34% water, and 1% styrene-acrylic emulsion by mass percentage.

[0071] S3. Determine the soft soil area to be grouted according to the construction plan, inject soft soil solidification material into the soft soil within the required range using grouting equipment, and cure for 7 to 28 days to form solidified soft soil bearing layer 3. After curing, test the soil strength to ensure that the unconfined compressive strength of solidified soft soil bearing layer 3 is not less than 2.5 MPa.

[0072] The specific construction method for solidified soft soil bearing layer 3 is as follows:

[0073] B1. Arrange the grouting hole positions according to the soft soil conditions and the marked pile positions. Drill holes at the grouting hole positions using a drilling rig or hand drill to the required depth to obtain the grouting holes, and explore the geological conditions.

[0074] B2. Grouting is carried out using grouting equipment, which includes grouting nozzle and grouting pump 1. The grouting nozzle has a grouting through hole on its pipe wall near its bottom end. During grouting, the bottom end of the grouting nozzle 2 is inserted into the grouting hole, and the top end of the grouting nozzle 2 is connected to the grouting pump 1.

[0075] B3. The soft soil stabilization material is continuously injected into the soft soil in sections through grouting pump 1 and grouting jet pipe 2.

[0076] Specifically, the soft soil stabilizing material is injected into the soft soil layer through the grouting nozzle 2 using the grouting pump 1. The grouting material penetrates into the pores of the soil layer. The grouting material should be injected continuously in one go without interruption. Grouting should start with a thin grout and gradually thicken it. The grouting sequence is generally as follows: after the grouting nozzle 2 is submerged to the full depth in one go, grouting is carried out continuously in sections from bottom to top, and the nozzle is pulled out in sections until the borehole opening is reached. Specifically, the grouting nozzle 2 is inserted into the grouting hole to a certain depth. During grouting, the grouting nozzle 2 continuously injects grout into the grouting hole. After each grouting period, the grouting nozzle 2 is lifted a certain distance. Grouting is not interrupted during the lifting process until the bottom end of the grouting nozzle 2 is lifted to the borehole opening.

[0077] B4. After grouting is completed, slowly pull out the grouting nozzle 2 and seal the grouting hole.

[0078] B5. Carry out maintenance and monitoring to ensure that the solidification effect of soft soil meets the requirements.

[0079] S4. Before the soft soil bearing layer 3 reaches the required strength, the FRP-steel honeycomb web photovoltaic pile foundation 4 shall be constructed by driving method or static pressure method.

[0080] Specifically, when using the static pressure method for construction, the piling equipment can be a static pile driver; when using the driving method for construction, the piling equipment can be a vibratory hammer pile driver.

[0081] When using the driving method, first use pile driving equipment, such as a vibratory hammer pile driver, to hammer the pile foundation with low energy, low stroke, or empty hammer. After confirming that there is no abnormality in the direction of pile penetration, continue normal hammering. After the pile bottom reaches the solidified soft soil bearing layer 3, ensure that the pile top is still 1.5m above the ground surface. After the pile foundation construction is completed, conduct strength and stability tests on each pile foundation.

[0082] After the construction of S5, FRP-steel honeycomb web photovoltaic pile foundation 4 is completed, clamp 5 is fitted on the top of the pile foundation and the clamp 5 is tightened in the required position.

[0083] S6. Install the photovoltaic bracket 6 and photovoltaic panel 7 on the clamp 5 to complete the pile foundation construction.

[0084] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A photovoltaic pile foundation with FRP-steel honeycomb web for solidified soft soil bearing layer, characterized in that: The soft soil area includes a soft soil solidification material and an FRP-steel honeycomb web photovoltaic pile foundation (4). The soft soil area is a solidified soft soil bearing layer (3). The bottom of the FRP-steel honeycomb web photovoltaic pile foundation (4) is buried in the solidified soft soil bearing layer (3), and the top of the FRP-steel honeycomb web photovoltaic pile foundation (4) extends to above the ground. The FRP-steel honeycomb web photovoltaic pile foundation (4) includes a cylindrical core mold, concrete (10) and a wound fiber layer (8). The core mold includes a cross-shaped steel column (11) and four FRP sleeves (9). The web of the cross-shaped steel column (11) is provided with honeycomb-shaped through holes. The FRP sleeves (9) are in the shape of a quarter circle. Both straight plates of the FRP sleeves (9) are provided with honeycomb-shaped through holes. The four FRP sleeves (9) are respectively fixed between two adjacent webs of the cross-shaped steel column (11). The number and position of the through holes on the straight plate of each FRP sleeve (9) correspond to the number of through holes on the web of the corresponding cross-shaped steel column (11). The concrete (10) is poured into the FRP sleeves (9). The wound fiber layer (8) is located on the outside of the core mold. Prefabricated cross-shaped steel column (11) and FRP sleeve (9) are connected by epoxy resin curing, and the two are fixed together to form a core mold; The soft soil stabilization material includes granulated blast furnace slag, fly ash, carbide slag, phosphogypsum, straw fiber, alkali activator, and water; the percentage of each material is as follows: granulated blast furnace slag 15%~20%, fly ash 8%~12%, carbide slag 3%~6%, phosphogypsum 5%~10%, straw fiber 0.8%~1.2%, alkali activator 0.5%~1%, and water 10%~15%.

2. The photovoltaic pile foundation with FRP-steel honeycomb web in solidified soft soil bearing layer according to claim 1, characterized in that: The solidified soft soil bearing layer (3) is located within a range of 2 / 3 of the pile length upward and 1 / 3 of the pile length downward from the bottom of the FRP-steel honeycomb web photovoltaic pile foundation (4).

3. The photovoltaic pile foundation with FRP-steel honeycomb web in solidified soft soil bearing layer according to claim 1, characterized in that, The preparation method of the FRP-steel honeycomb web photovoltaic pile foundation (4) is as follows: Each cross-shaped steel column (11) is provided with an FRP sleeve (9) between two adjacent web plates, and the through holes on the straight edge plate of the FRP sleeve (9) correspond one-to-one with the through holes on the web plate of the cross-shaped steel column (11). A fiber composite material is wound around the outer surface of the mandrel to form a wound fiber layer on the outer side of the mandrel (8).

4. The photovoltaic pile foundation with FRP-steel honeycomb web in solidified soft soil bearing layer according to claim 3, characterized in that, The preparation process of the wound fiber layer (8) is as follows: the fiber composite material is directly impregnated with resin under tension, and the impregnated fiber composite material is continuously wound onto the outer surface of the mandrel according to the wet winding molding process. The number of winding layers is at least four layers, and the winding angle of each layer of fiber composite material is 75 degrees, 60 degrees, 45 degrees and 30 degrees from the inside to the outside. After the winding is completed, the wound fiber layer (8) is obtained by heating and curing. The fibers in the fiber composite material are any one of carbon fiber, glass fiber, basalt fiber, and hybrid fiber.

5. The photovoltaic pile foundation with FRP-steel honeycomb web in solidified soft soil bearing layer according to claim 3, characterized in that, The manufacturing process of the FRP sleeve (9) is as follows: first, fiber yarn is prepared from fiber reinforced composite material, then the fiber yarn is impregnated with resin, and finally the FRP sleeve (9) is obtained by integral pultrusion molding process. The impregnation resin is any one of unsaturated resin, vinyl resin, epoxy resin, and phenolic resin, and the fiber material in the fiber-reinforced composite material is any one of carbon fiber, glass fiber, basalt fiber, and hybrid fiber.

6. A construction method for a photovoltaic pile foundation with FRP-steel honeycomb web in a solidified soft soil bearing layer, implemented based on the photovoltaic pile foundation with FRP-steel honeycomb web in a solidified soft soil bearing layer as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Determine the pile foundation depth, mark the pile positions, clear debris, level and initially compact the land, and pave the construction site. S2. Investigate geological conditions, determine construction plans, and prepare soft soil consolidation materials; S3. Determine the soft soil area to be grouted according to the construction plan, inject soft soil solidification material into the soft soil within the required range using grouting equipment, and cure for 7 to 28 days to form a solidified soft soil bearing layer (3). After curing, test the soil strength to ensure that the unconfined compressive strength of the solidified soft soil bearing layer (3) is not less than 2.5 MPa. S4. Before the soft soil bearing layer (3) to be solidified reaches the strength requirement, the FRP-steel honeycomb web photovoltaic pile foundation (4) is constructed by driving method or static pressure method. After the construction of S5, FRP-steel honeycomb web photovoltaic pile foundation (4) is completed, a clamp (5) is fitted on the top of the pile foundation and the clamp (5) is tightened in the required position; S6. Install the photovoltaic bracket (6) and photovoltaic panel (7) on the clamp (5) to complete the pile foundation construction; The preparation method of the soft soil solidification material in step S2 is as follows: A1. Based on the geological survey results and construction requirements, the proportions of granulated blast furnace slag, carbide slag, phosphogypsum, straw fiber, alkali activator, and water are adjusted to determine the proportions of each material to meet construction requirements. A2. Granulated blast furnace slag, carbide slag, phosphogypsum, straw fiber, and water are added to a mixer according to the specified ratio and mixed to obtain a fluidized mixture. A3. After the plasticizing mixture is stirred evenly, add the alkali activator into the mixer and continue stirring. After the plasticizing mixture and the alkali activator are stirred evenly, the soft soil solidification material is obtained.

7. The construction method of a photovoltaic pile foundation with FRP-steel honeycomb web in solidified soft soil bearing layer according to claim 6, characterized in that, The specific construction method for solidifying the soft soil bearing layer (3) in step S3 is as follows: B1. Arrange the grouting hole positions according to the soft soil conditions and the marked pile positions. Drill holes at the grouting hole positions using a drilling rig or hand drill to the required depth to obtain the grouting holes, and explore the geological conditions. B2. Grouting is carried out using grouting equipment, which includes grouting nozzle (2) and grouting pump (1). The grouting nozzle (2) has a grouting through hole on the pipe wall near its bottom end. During grouting, the bottom end of the grouting nozzle (2) is inserted into the grouting hole, and the top end of the grouting nozzle (2) is connected to the grouting pump (1). B3. The soft soil solidification material is continuously injected into the soft soil in sections through the grouting pump (1) and the grouting jet pipe (2); B4. After grouting is completed, slowly pull out the grouting nozzle (2) and seal the grouting hole. B5. Carry out maintenance and monitoring to ensure that the solidification effect of soft soil meets the requirements.

8. The construction method of a photovoltaic pile foundation with FRP-steel honeycomb web in solidified soft soil bearing layer according to claim 6, characterized in that, The construction process of the FRP-steel honeycomb web photovoltaic pile foundation (4) in step S4 is as follows: When the driving method is used, the pile foundation is first hammered with low energy, low stroke or empty hammer using the pile driving equipment. After confirming that there is no abnormality in the direction of pile penetration, continuous normal hammering is then carried out. After the bottom of the pile reaches the solidified soft soil bearing layer (3), ensure that the top of the pile is still 1.5m above the ground surface. After the pile foundation construction is completed, strength and stability tests are carried out on each pile foundation.

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