Heavy storage yard multi-pile type composite foundation and construction method

Abstract

The invention relates to the related technical field of foundation construction, in particular to a heavy storage yard multi-pile type composite foundation and a construction method.The heavy storage yard multi-pile type composite foundation comprises a foundation layer, a mattress layer is laid below the foundation layer, concrete piles are arranged below the mattress layer, CFG piles are distributed on the outer rings of the concrete piles at equal intervals, and the CFG piles are arranged on the outer rings of the concrete piles at equal intervals; an outer reinforcement cage is arranged in the concrete pile, and an inner reinforcement cage is arranged on the inner ring of the outer reinforcement cage. According to the heavy storage yard multi-pile type composite foundation and the construction method, through cooperation of the concrete piles and the CFG piles, the physical and mechanical properties of shallow foundation soil are improved, the overall stability of the foundation is improved, normal use of the heavy storage yard is guaranteed, the concrete piles transmit upper loads to a deep foundation, the CFG piles reinforce the shallow foundation, and the construction efficiency of the heavy storage yard is improved. The two structures jointly bear the load transmitted from the upper structure, the bearing capacity of the composite foundation is remarkably improved, and the requirement for huge loads of large equipment, goods and the like in a heavy storage yard is met.

Description

Technical Field

[0001] The present invention relates to the technical field related to foundation construction, and particularly relates to a multi-pile type composite foundation for a heavy-duty yard and a construction method thereof. Background Technique

[0002] A heavy-duty yard refers to a site for stacking heavy goods, equipment or materials, which is relatively common in fields such as ports, logistics, and industry. The heavy-duty yard needs to bear the huge pressure of heavy goods and equipment, so the requirements for the bearing capacity of the foundation are extremely high. It is necessary to ensure that the foundation can stably support the stacked heavy objects. The multi-pile type composite foundation is suitable for treating normally consolidated soil with relatively hard layers at different depths, or special soils such as under-consolidated soil, collapsible loess, and liquefiable soil in the shallow layer, as well as foundations with higher requirements for foundation bearing capacity and deformation, which meet the high requirements of the heavy-duty yard for the bearing capacity and stability of the foundation. Therefore, a multi-pile type composite foundation for a heavy-duty yard and a construction method thereof are needed.

[0003] For the existing multi-pile type composite foundation and construction method for a heavy-duty yard, due to the complex foundation conditions of the heavy-duty yard and the large differences in the properties of soil layers at different depths, during foundation construction, excessive settlement or differential settlement will affect the normal use of the heavy-duty yard and may even cause structural damage to the building. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-pile type composite foundation for a heavy-duty yard and a construction method thereof to solve the problem that in the existing multi-pile type composite foundation and construction method for a heavy-duty yard, due to the complex foundation conditions of the heavy-duty yard and the large differences in the properties of soil layers at different depths, during foundation construction, excessive settlement or differential settlement will affect the normal use of the heavy-duty yard and may even cause structural damage to the building as mentioned in the above background technique.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A multi-pile type composite foundation for a heavy-duty yard and a construction method thereof, including a base layer, a cushion layer is laid below the base layer, a concrete pile is arranged below the cushion layer, CFG piles are evenly distributed around the outer circle of the concrete pile, an outer steel reinforcement cage is arranged inside the concrete pile, and an inner steel reinforcement cage is arranged inside the inner circle of the outer steel reinforcement cage.

[0006] Preferably, the cushion layer includes a sand and gravel layer laid on the surface of the foundation, and a geogrid layer is laid on the upper surface of the sand and gravel layer.

[0007] Preferably, the outer steel reinforcement cage includes a first steel ring. The surface of the first steel ring is penetrated and welded with first steel bars. Through holes are equidistantly formed on the surface of the lowermost first steel ring. A limiting groove is formed at the connection between the outer ring of the first steel bar and the through hole. One end of the through hole penetrates through a steel plate. An arc-shaped plate is fixedly installed at the upper end of the steel plate. A hook angle is integrally formed on one end surface of the steel plate.

[0008] Preferably, the through holes are inclined, and the hook angle of the steel plate matches the structure of the limiting groove.

[0009] Preferably, the inner steel reinforcement cage includes a second steel ring. The surface of the second steel ring is penetrated and welded with second steel bars. One end of the second steel bar penetrating through the lowermost second steel ring is welded with a diagonal tension steel bar.

[0010] Preferably, multiple groups of the diagonal tension steel bars form a conical structure, and an outward convex structure is arranged on the outer ring of the lowermost second steel ring. The lowermost second steel ring and the diagonal tension steel bars cooperate to push the arc-shaped plate downward.

[0011] A construction method for a multi-pile type composite foundation in a heavy yard is as follows: S1. Use total station and theodolite surveying instruments to accurately mark the positions of the concrete piles on site. The pile position deviation should not exceed ±20 mm. S2. Move the drilling rig to the pile position, align and level it to ensure that the drill pipe is vertical. During the drilling process, control the drilling speed and pressure to ensure that the verticality and diameter of the drill hole meet the design requirements. When the drilling reaches the design depth, carry out hole cleaning to remove the sediment and debris at the bottom of the hole to ensure that the bottom of the hole is clean and tidy. S3. After the drilling is completed, first lift the casing into the hole, then lift the outer steel reinforcement cage into the hole along the center position of the casing and fix it. Subsequently, lift the inner steel reinforcement cage from above the outer steel reinforcement cage and squeeze the inner steel reinforcement cage so that the diagonal tension steel bars below the inner steel reinforcement cage cooperate with the second steel ring to squeeze the arc-shaped plate, pushing the steel plate to extend to the outside below the casing and embed with the underlying soil layer. S4. Use the conduit method for concrete pouring. The concrete mix ratio should be prepared strictly in accordance with the design requirements. While pouring and vibrating, slowly pull out the casing. When the concrete is poured to a certain height (0.5 - 1.0 m) above the design elevation of the pile top, stop pouring and promptly carry out pile top treatment, such as chiseling off the excess concrete and leveling the pile top. S5. After the concrete piles are constructed, according to the design drawings and the positions of the long piles, accurately mark the positions of the CFG piles. S6. Select a drilling device suitable for CFG pile construction, such as a long spiral drilling rig. During drilling, control the diameter, depth and verticality of the drill hole according to the design requirements. During the drilling process, it is necessary to continuously check the quality of the drilled holes, such as the hole diameter, hole depth, verticality, etc., to ensure that the drilled holes meet the design requirements; S7. Adopt the construction technology of long - spiral drilling and pumping the mixture in the pipe to form a pile. Pump the well - stirred mixture into the drill pipe through a concrete pump, and then lift while rotating the drill pipe to form a pile body in the hole; During the construction process, control the drill - lifting speed and pumping pressure to ensure the density and uniformity of the pile body. The drill - lifting speed should not be too fast, controlled at 2 - 4 m / min. After the pile is formed, level the top of the pile to ensure that the pile top elevation meets the design requirements; S8. After the pile body construction is completed, lay the cushion layer in a timely manner. First, lay the sand - gravel layer, and then lay the geogrid layer on the sand - gravel layer.

[0012] Preferably, four groups of CFG piles are evenly distributed at equal intervals with the concrete pile as the center. The depth of the concrete pile is 26 m, and the depth of the CFG pile is 15 m.

[0013] Preferably, the thickness of the sand - gravel layer is 15 cm - 20 cm.

[0014] Compared with the prior art, the beneficial effects of the present invention are: Through the cooperation of the concrete pile and the CFG pile, the concrete pile can penetrate into the deep solid soil layer, which can effectively control the vertical deformation of the foundation. The CFG pile is mainly used to treat the shallow foundation, improve the physical and mechanical properties of the shallow foundation soil, and improve the overall stability of the foundation, avoiding problems such as building inclination and cracking caused by uneven settlement, ensuring the normal use of the heavy - duty yard. The concrete pile transfers the upper load to the deep foundation, and the CFG pile reinforces the shallow foundation. The two jointly bear the load transmitted from the upper structure, significantly improving the bearing capacity of the composite foundation and meeting the requirements of huge loads such as large - scale equipment and goods in the heavy - duty yard.

[0015] Through the setting of the cushion layer, the combination of the sand - gravel layer and the geogrid layer can improve the mechanical properties of the foundation soil. The sand - gravel layer has high water permeability and inter - granular friction, which can improve the drainage performance and shear strength of the foundation. The geogrid layer can restrain the lateral deformation of the soil body, increase the density and stability of the soil body. The two cooperate with each other, enabling the cushion layer to better play its reinforcement role and improving the overall stability of the foundation.

[0016] Through the arrangement of the outer steel reinforcement cage and the inner steel reinforcement cage, the concrete itself has high compressive strength, and the steel bars have good tensile properties. After the two are combined, the reinforced concrete pile can not only bear a large vertical pressure, but also resist a certain horizontal tensile force. At the same time, after the inner steel reinforcement cage is pressed down, the steel plate can be pushed downward, so that the steel plate extends into the lower soil layer, and the outward-expanded structure can increase the firmness of the connection between the concrete pile and the soil layer after forming. Brief Description of the Drawings

[0017] Figure 1 Schematic cross-sectional structure diagram of the concrete pile of the present invention; Figure 2 Schematic overall appearance structure diagram of the present invention; Figure 3 Schematic structure diagram of the outer steel reinforcement cage of the present invention; Figure 4 Schematic structure diagram of the inner steel reinforcement cage of the present invention; Figure 5 Schematic structure diagram of the mutual cooperation between the first steel ring and the steel plate of the present invention; Figure 6 Schematic cross-sectional structure diagram of the first steel ring of the present invention; Figure 7 Schematic diagram of the layered structure of the cushion layer of the present invention.

[0018] In the figure: 1, base layer; 2, cushion layer; 201, sand and gravel layer; 202, geogrid layer; 3, concrete pile; 4, CFG pile; 5, outer steel reinforcement cage; 501, first steel ring; 502, first steel bar; 503, through hole; 504, limiting groove; 505, steel plate; 506, arc plate; 507, hook angle; 6, inner steel reinforcement cage; 601, second steel ring; 602, second steel bar; 603, inclined tension bar. Detailed Description of the Invention

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] Please refer to Figure 1-7 , the present invention provides a technical solution: a multi-pile type composite foundation and construction method for a heavy yard, including a base layer 1, a cushion layer 2 is laid below the base layer 1, a concrete pile 3 is arranged below the cushion layer 2, CFG piles 4 are evenly distributed on the outer circle of the concrete pile 3, and an outer steel reinforcement cage 5 is arranged inside the concrete pile 3, and an inner steel reinforcement cage 6 is arranged inside the outer steel reinforcement cage 5.

[0021] Furthermore, the cushion layer 2 includes a sand and gravel layer 201 laid on the surface of the foundation. A geogrid layer 202 is laid on the upper surface of the sand and gravel layer 201. Through the setting of the cushion layer 2, the cushion layer 2 is located between the base layer 1 and the pile body, and is composed of a sand and gravel layer 201 with a thickness of 15 - 20 cm and a geogrid layer 202. The sand and gravel layer 201 provides high water permeability and inter-particle friction, and the geogrid layer 202 restricts the lateral deformation of the soil body. The combination of the two forms a flexible transition layer to balance the stress distribution between the pile and the soil.

[0022] Furthermore, the outer steel reinforcement cage 5 includes a first steel ring 501. The surface of the first steel ring 501 is penetrated and welded with a first steel bar 502. Through holes 503 are equidistantly arranged on the surface of the lowermost first steel ring 501. A limiting groove 504 is formed at the connection between the outer ring of the first steel bar 502 and the through hole 503. One end of the through hole 503 is penetrated by a steel plate 505. An arc-shaped plate 506 is fixedly installed at the upper end of the steel plate 505. A hook angle 507 is integrally formed on one end surface of the steel plate 505. Through the setting of the outer steel reinforcement cage 5, the outer steel reinforcement cage 5 and the inner steel reinforcement cage 6 jointly form the steel reinforcement framework of the pile body. The first steel bar 502 is penetrated and welded on the surface of the first steel ring 501 of the outer steel reinforcement cage 5 to form a stable annular stress-bearing structure. When the pile body bears the upper load, the outer steel reinforcement cage 5 and the inner steel reinforcement cage 6 cooperate with each other to better disperse the stress, enabling the pile body to bear greater forces in both the vertical and horizontal directions, enhancing the bearing capacity of the entire pile body, and meeting the requirements of huge loads such as large-scale equipment and goods in heavy-duty yards.

[0023] Furthermore, the through hole 503 is inclined, and the hook angle 507 of the steel plate 505 is matched with the structure of the limiting groove 504. Through the setting of the through hole 503, the through hole 503 and the limiting groove 504 can limit the steel plate 505. The inclined through hole 503 can define the moving direction of the steel plate 505, causing the steel plate 505 to expand outward. The limiting groove 504 and the hook angle 507 are in contact with each other, which can prevent the steel plate 505 from falling off when it is initially placed. For the arc-shaped plate 506 at the other end of the steel plate 505, when the steel plate 505 is initially placed, the arc-shaped plate 506 is at the highest end, and the highest end position still remains outside the outer ring of the inclined stay bar 603. No matter what position the arc-shaped plate 506 is in, it will not affect the downward pressure of the inner steel reinforcement cage 6. When the inner steel reinforcement cage 6 presses downward, the arc-shaped plate 506 cooperates with the outer ring of the inclined stay bar 603 to push the steel plate 505 to move.

[0024] Further, the inner steel reinforcement cage 6 includes a second steel ring 601. The surface of the second steel ring 601 is penetrated and welded with second steel bars 602. One end of the second steel bars 602 that penetrates the lowermost second steel ring 601 is welded with stay bars 603. Through the setting of the inner steel reinforcement cage 6, the structural design of the outer steel reinforcement cage 5 enables the stay bars 603 below the inner steel reinforcement cage 6 to cooperate with the second steel ring 601 to extrude the arc-shaped plate 506, pushing the steel plate 505 to extend to the outside of the lower part of the casing and fit with the underlying soil layer. This mechanical interlocking effect greatly enhances the connection force between the concrete pile 3 and the surrounding soil layer, enabling the concrete pile 3 to better transfer the upper load to the foundation soil layer, improving the overall stability of the composite foundation. The steel plate 505 extends into the soil layer, which is equivalent to expanding the bearing area of the pile tip, reducing the pressure per unit area at the end of the concrete pile 3, and reducing the possibility of settlement at the end of the concrete pile 3, further improving the bearing capacity and stability of the pile body.

[0025] Further, multiple groups of stay bars 603 form a conical structure, and an outward convex structure is provided on the outer circumference of the lowermost second steel ring 601. The lowermost second steel ring 601 cooperates with the stay bars 603 to push the arc-shaped plate 506 downward. Through the setting of the stay bars 603, the conical structure formed by multiple groups of stay bars 603 can simultaneously extrude multiple groups of arc-shaped plates 506.

[0026] A construction method for a multi-pile type composite foundation in a heavy-duty yard is as follows: S1. Use total station and theodolite surveying instruments to accurately mark the positions of the concrete piles 3 on site, and the pile position deviation should not exceed ±20 mm; S2. Move the drilling rig to the pile position, perform centering and leveling to ensure that the drill pipe is vertical. During the drilling process, control the drilling speed and pressure to ensure that the verticality and diameter of the drilled hole meet the design requirements; When the drilling reaches the design depth, perform hole cleaning to remove the sediment and debris at the bottom of the hole to ensure that the bottom of the hole is clean and tidy; S3. After the drilling is completed, first lift the casing into the hole, then lift the outer steel reinforcement cage 5 into the hole along the central position of the casing and fix it. Subsequently, lift the inner steel reinforcement cage 6 into the hole from above the outer steel reinforcement cage 5 and squeeze the inner steel reinforcement cage 6, enabling the stay bars 603 below the inner steel reinforcement cage 6 to cooperate with the second steel ring 601 to extrude the arc-shaped plate 506, pushing the steel plate 505 to extend to the outside of the lower part of the casing and fit with the underlying soil layer; S4. Use the conduit method for concrete pouring. The concrete mix ratio should be prepared strictly in accordance with the design requirements. While pouring and vibrating the concrete, slowly pull out the casing. When the concrete is poured to a certain height (0.5 - 1.0 m) above the design elevation of the pile top, stop pouring and promptly perform pile top treatment, such as chiseling off the excess concrete and leveling the pile top; S5. After the construction of the concrete pile 3 is completed, according to the design drawings and the position of the long pile, accurately mark the position of the CFG pile 4 and make marks; S6. Select a drilling equipment suitable for the construction of the CFG pile 4, such as a long auger drilling rig. During drilling, control the diameter, depth and verticality of the drilling according to the design requirements; During the drilling process, continuously check the quality of the drilling, such as the hole diameter, hole depth, verticality, etc., to ensure that the drilling meets the design requirements; S7. Adopt the construction technology of long auger drilling and pumping the mixture in the pipe to form a pile. Pump the mixed material into the drill pipe through a concrete pump, and then rotate the drill pipe and lift it at the same time, so that the mixed material forms a pile body in the hole; During the construction process, control the drill lifting speed and pumping pressure to ensure the density and uniformity of the pile body. The drill lifting speed should not be too fast, controlled at 2-4 m / min. After the pile is formed, level the top of the pile to ensure that the pile top elevation meets the design requirements; S8. After the construction of the pile body is completed, lay the cushion layer 2 in time. First lay the sand and gravel layer 201, and then lay the geogrid layer 202 on the sand and gravel layer 201.

[0027] Further, four groups of CFG piles 4 are evenly distributed at equal intervals with the concrete pile 3 as the center, and the depth of the concrete pile 3 is 26 m, and the depth of the CFG pile 4 is 15 m.

[0028] Further, the thickness of the sand and gravel layer 201 is 15 cm - 20 cm.

[0029] Working principle: First, accurately calibrate the positions of the concrete pile 3 and the CFG pile 4 through surveying instruments such as total stations and theodolites, then drill holes according to the positions. Subsequently, in the construction hole of the concrete pile 3, hoist and press the casing into the hole, and then lower the outer steel reinforcement cage 5. After the bottom of the outer steel reinforcement cage 5 contacts the bottom of the hole, lower the inner steel reinforcement cage 6. When the inner steel reinforcement cage 6 is lowered, the inclined tension bar 603 squeezes the arc plate 506 at the bottom of the outer steel reinforcement cage 5, driving the steel plate 505 to extend outward along the inclined through hole 503. After the steel plate 505 extends into the soil layer, it is embedded with the surrounding soil. Adopt the conduit method to pour concrete in layers, pull out the pipe while pouring, stop when pouring to 0.5 - 1.0 m above the pile top elevation, and chisel off the excess part and level the pile top. Subsequently, four groups of CFG piles 4 are evenly distributed at equal intervals with the concrete pile 3 as the center. After forming a hole with a long auger drilling rig, pump the mixture in the pipe to form a pile. After the construction of the pile body is completed, first lay a 15 - 20 cm thick sand and gravel layer 201, then lay the geogrid layer 202 to restrain the lateral deformation of the soil body. Finally, remove the sundries, garbage, etc. on the surface of the cushion layer 2 to ensure that the construction surface is clean and tidy. Select a suitable formwork material according to the shape and size of the base layer 1, and adopt the method of layered pouring to form the base layer 1 mainly composed of concrete.

[0030] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-pile type composite foundation for a heavy yard, comprising a base layer (1), characterized in that: A cushion layer (2) is laid below the base layer (1), a concrete pile (3) is arranged below the cushion layer (2), CFG piles (4) are evenly distributed around the outer circle of the concrete pile (3), an outer steel reinforcement cage (5) is arranged inside the concrete pile (3), and an inner steel reinforcement cage (6) is arranged inside the inner circle of the outer steel reinforcement cage (5).

2. The multi-pile type composite foundation for a heavy-duty yard according to claim 1, characterized in that: The cushion layer (2) includes a sand and gravel layer (201) laid on the surface of the foundation, and a geogrid layer (202) is laid on the upper surface of the sand and gravel layer (201).

3. A multi-pile type composite foundation for a heavy-duty yard according to claim 1, characterized in that: The outer steel reinforcement cage (5) includes a first steel ring (501), a first steel bar (502) penetrates and is welded to the surface of the first steel ring (501), through holes (503) are evenly formed in the surface of the lowermost first steel ring (501), a limiting groove (504) is formed at the connection between the outer circle of the first steel bar (502) and the through hole (503), a steel plate (505) penetrates through one end of the through hole (503), the steel plate (505), an arc-shaped plate (506) is fixedly installed at the upper end of the steel plate (505), and a hook angle (507) is integrally formed on one end surface of the steel plate (505).

4. A multi-pile type composite foundation for a heavy-duty yard according to claim 3, characterized in that: The through hole (503) is inclined, and the hook angle (507) of the steel plate (505) is matched with the structure of the limiting groove (504).

5. The multi-pile type composite foundation for a heavy-duty yard according to claim 1, characterized in that: The inner steel reinforcement cage (6) includes a second steel ring (601), a second steel bar (602) penetrates and is welded to the surface of the second steel ring (601), and a stay bar (603) is welded to one end of the second steel bar (602) penetrating through the lowermost second steel ring (601).

6. The multi-pile type composite foundation for heavy yard according to claim 5, wherein: Multiple groups of the stay bars (603) form a conical structure, and an outward convex structure is arranged on the outer circle of the lowermost second steel ring (601). The lowermost second steel ring (601) cooperates with the stay bars (603) to push the arc-shaped plate (506) downward.

7. A construction method for a multi-pile type composite foundation in a heavy-duty yard. For a multi-pile type composite foundation in a heavy-duty yard as described in any one of the above claims, it is characterized in that, The specific steps are as follows: S1. Use total station and theodolite measuring instruments to accurately set out the position of the concrete pile (3) on site and make marks. The pile position deviation shall not exceed ±20 mm; S2. Move the drilling machine to the pile position, perform centering and leveling to ensure that the drill pipe is vertical. During the drilling process, control the drilling speed and pressure to ensure that the verticality and diameter of the drill hole meet the design requirements; When the drilling reaches the design depth, perform hole cleaning to remove the sediment and debris at the bottom of the hole to ensure that the bottom of the hole is clean and tidy; S3. After the drilling is completed, first lift the casing into the hole, then lift the outer steel reinforcement cage (5) into the hole along the central position of the casing and fix it. Subsequently, lift the inner steel reinforcement cage (6) from above the outer steel reinforcement cage (5) and squeeze the inner steel reinforcement cage (6) so that the stay bars (603) below the inner steel reinforcement cage (6) cooperate with the second steel ring (601) to squeeze the arc-shaped plate (506) and push the steel plate (505) to extend to the outside below the casing and fit with the underlying soil layer; S4. The concrete is poured by the conduit method. The mix proportion of the concrete shall be prepared strictly in accordance with the design requirements. While pouring and vibrating the concrete, the casing shall be slowly pulled out. When the concrete is poured to a certain height (0.5 - 1.0 m) above the design elevation of the pile top, the pouring shall be stopped, and the pile top shall be treated in time, such as chiseling off the excess concrete and leveling the pile top. S5. After the construction of the concrete pile (3) is completed, according to the design drawings and the position of the long pile, accurately set out the position of the CFG pile (4) and make marks. S6. Select a drilling equipment suitable for the construction of the CFG pile (4), such as a long auger drilling rig. During drilling, control the diameter, depth and verticality of the drilling according to the design requirements. During the drilling process, continuously check the quality of the drilling, such as the hole diameter, hole depth and verticality, to ensure that the drilling meets the design requirements. S7. Adopt the construction technology of long auger drilling and pumping the mixture in the pipe to form a pile. The mixed material that has been stirred is pumped into the drill pipe through a concrete pump, and then the drill pipe is rotated and lifted at the same time, so that the mixed material forms a pile body in the hole. During the construction process, control the drill lifting speed and the pumping pressure to ensure the density and uniformity of the pile body. The drill lifting speed should not be too fast, controlled at 2 - 4 m / min. After the pile is formed, level the pile top to ensure that the pile top elevation meets the design requirements. S8. After the construction of the pile body is completed, lay the cushion layer (2) in time. First, lay the sand and gravel layer (201), and then lay the geogrid layer (202) on the sand and gravel layer (201).

8. The construction method of a multi-pile type composite foundation for a heavy-duty yard according to claim 7, characterized in that: The four groups of CFG piles (4) are evenly distributed at equal intervals with the concrete pile (3) as the center, and the depth of the concrete pile (3) is 26 m, and the depth of the CFG pile (4) is 15 m.

9. The construction method of a multi-pile type composite foundation for a heavy yard according to claim 7, characterized in that: The thickness of the sand and gravel layer (201) is 15 cm - 20 cm.

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