Modularized assembly type double-row HU construction method pile supporting structure and construction method thereof

Abstract

The modular assembly type double-row HU construction method pile supporting structure comprises a front row of parallel HU construction method piles and a rear row of parallel HU construction method piles, each row of HU construction method piles is composed of H-shaped steel piles and U-shaped steel sheet piles, the U-shaped steel sheet piles are meshed with one another through locking openings to form a continuous steel sheet pile wall, the H-shaped steel piles are inserted between the steel sheet pile walls formed by the U-shaped steel sheet piles, and the H-shaped steel piles and the U-shaped steel sheet piles are arranged in parallel. Top beam outer side steel plates are arranged on the outer sides of the tops of the H-shaped steel piles, top beam inner side steel plates and connecting beam modules are arranged on the inner sides of the tops of the front row of H-shaped steel piles and the inner sides of the tops of the rear row of H-shaped steel piles, and soil between piles of the double-row steel plate pile wall and soil in a passive area of the foundation pit are reinforced through double-shaft or three-shaft cement mixing piles. The double-row HU construction method pile enclosure structure is composed of the front row of parallel HU construction method piles, the rear row of parallel HU construction method piles, the prefabricated assembly type top beams, the connecting beams and other main components, the overall stability and bearing capacity of the structure are enhanced, and the double-row HU construction method pile enclosure structure has the advantages of being good in water stopping effect, flexible and rapid in construction, economical, environmentally friendly and the like.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a modular assembled double-row HU construction method pile support structure and a construction method thereof. Background Art

[0002] With the acceleration of urbanization and the continuous development of construction projects, the safety and environmental protection requirements of foundation pit projects are becoming higher and higher. Although traditional foundation pit retaining technologies such as Larsen steel sheet piles and SMW method piles have met the engineering needs to a certain extent, they have certain limitations in terms of stiffness, water stopping, construction speed, etc. Therefore, HU method piles came into being as a new foundation pit retaining technology.

[0003] HU method piles refer to a foundation pit retaining structure that has both high-strength supporting capacity and good water-stopping effect, formed by combining H-shaped steel and Larsen steel sheet piles in a specific way. H-shaped steel is the main supporting structure, providing high-strength supporting force; Larsen steel sheet piles use their good water-stopping performance to form an effective water-stopping curtain. HU method piles have fast construction speed, strong adaptability, and good water-stopping effect, but the pile body is easy to deform and its scope of application is limited.

[0004] Double-row piles are a retaining structure composed of a rigid frame and a crown beam connected by two rows of support piles and beams arranged along the side wall of the foundation pit. They have high overall rigidity. Under the action of complex and variable external loads, they can automatically adjust the internal force of the structure itself and have strong adaptability. However, the crown beams of double-row piles are mostly cast-in-place reinforced concrete structures, which have a long construction period, high cost, and poor environmental performance.

[0005] For soft soil strata with thick silt layers, the foundation pit support system must be able to effectively control the horizontal displacement of the foundation pit retaining structure and the settlement of the soil around the foundation pit, while meeting the requirements of safety and stability while taking into account environmental protection and economy. Summary of the invention

[0006] The present invention aims to solve the problems existing in the prior art and aims to provide a modular assembled double-row HU method pile support structure and a construction method thereof. The structure combines the advantages of HU method piles and double-row piles, so that it has good safety, stability, environmental protection and economy.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A modular assembled double-row HU construction method pile support structure comprises two parallel rows of HU construction method piles, each row of HU construction method piles consists of H-shaped steel piles and U-shaped steel sheet piles, the U-shaped steel sheet piles are engaged with each other through locking joints to form a continuous steel sheet pile wall, the H-shaped steel piles are inserted between the steel sheet pile walls formed by the U-shaped steel sheet piles, a crown beam outer steel plate is arranged on the outer side of the top of the H-shaped steel piles, a crown beam inner steel plate and a connecting beam module are arranged on the inner side of the top of the front and rear rows of H-shaped steel piles, biaxial or triaxial cement mixing piles are used to reinforce the soil between the piles of the double-row steel sheet pile wall and the soil in the passive zone of the foundation pit, the soil between the piles is reinforced to the ground, the soil in the passive zone of the foundation pit is reinforced to the bottom plate of the foundation structure, and plain concrete is used to backfill between the bottom plate of the foundation structure and the surrounding structure.

[0009] The crown beam inner steel plate and connecting beam module includes a crown beam inner steel plate, a connecting beam, a crown beam inner steel plate longitudinal connecting plate and an inner steel plate tie rod hole. The crown beam inner steel plate and the connecting beam are welded into an "I" shape. A plurality of inner steel plate tie rod holes are opened on the crown beam inner steel plate. Opposite crown beam inner steel plate longitudinal connecting plates are welded at both ends of the crown beam inner steel plate.

[0010] The outer steel plate of the crown beam and the inner steel plate of the crown beam are connected by a tie rod, and the tie rod is located in the gap between two adjacent H-shaped steel piles.

[0011] A plurality of outer steel plate pull rod holes are provided on the outer steel plate of the crown beam, and longitudinal connecting plates of the outer steel plate of the crown beam are arranged at both ends of the outer steel plate of the crown beam.

[0012] The inner steel plate longitudinal connection plates of the inner steel plate of the crown beam and the outer steel plate longitudinal connection plates of the outer steel plate of the crown beam are connected by bolts.

[0013] A construction method of a modular assembled double-row HU construction method pile support structure, the steps of which are:

[0014] S1. Preliminary preparation: Complete the three connections and one leveling of the construction site to ensure that there are no obstacles in the construction area to facilitate the entry and exit of construction machinery and materials; conduct precise measurement and positioning to determine the position and elevation of the double-row steel sheet pile wall, and prepare the required H-shaped steel piles, U-shaped steel sheet piles, positioning frames and vibratory hammer construction materials and equipment;

[0015] S2. Cement mixing pile construction: Use biaxial or triaxial cement mixing piles to reinforce the soil between the piles of the double-row steel sheet pile wall and the soil in the passive area of ​​the foundation pit. The soil between the piles is reinforced to the ground, and the soil in the passive area of ​​the foundation pit is reinforced to the bottom plate of the foundation structure;

[0016] S3. HU method piles after construction: U-shaped steel sheet piles are driven in accordance with the design requirements, and they are interlocked with each other through the lock mouth to form a continuous steel sheet pile wall. The insertion depth of the H-shaped steel piles is determined according to the foundation pit depth and soil conditions. H-shaped steel piles are inserted between the water stop walls formed by the U-shaped steel sheet piles according to the design requirements;

[0017] S4. Construction of front row HU construction method piles: U-shaped steel sheet piles are driven in accordance with the design requirements, interlocked with each other through the locking mouth, and H-shaped steel piles are inserted between the water stop walls formed by the U-shaped steel sheet piles in accordance with the design requirements, and the spacing between them is half of the spacing between the rear row H-shaped steel piles;

[0018] S5. Assembly of prefabricated crown beams: an outer crown beam steel plate is set on the outer side of the top of the H-shaped steel pile, an inner crown beam steel plate and a connecting beam module are set on the inner side of the top of the H-shaped steel pile, and the inner crown beam steel plates of the front and rear rows of HU construction method piles are connected by connecting beams, and the inner crown beam steel plates and the connecting beams are connected by welding; the outer crown beam steel plates and the inner crown beam steel plates are connected by tie rods, and the tie rods are located in the gap between two adjacent H-shaped steel piles; the inner crown beam steel plate longitudinal connecting plates between the inner crown beam steel plates and the outer crown beam steel plate longitudinal connecting plates between the outer crown beam steel plates are connected by bolts. After the assembly of the crown beams on the top of the piles is completed and accepted, the foundation pit can be excavated immediately;

[0019] S6. Foundation construction of excavator: The excavation of foundation pit should be carried out in blocks. After the excavation reaches the bottom of the pit, the cushion layer should be constructed immediately. The excavated soil is strictly prohibited from being piled on the top of the slope. The overload value at the pit edge should be controlled not to exceed 20kPa. After the excavation is completed, the foundation project should be carried out as soon as possible. The base plate of the foundation structure and the surrounding structure should be filled with plain concrete with the same strength as the base plate of the foundation structure;

[0020] S7. Backfill of foundation pit: The backfill soil of foundation pit is backfilled in layers with silt sand and compacted with water. The backfill soil is 200~300mm above the ground.

[0021] S8. Recycling of related module components of double-row HU construction method piles: After the foundation pit backfill is compacted, the components are recycled. The static extraction process is used to first release the tie rods and bolt connections, recycle the prefabricated crown beams, then remove the H-shaped steel piles, and finally remove the U-shaped steel sheet piles. During the recycling process, pure cement slurry should be used for grouting at the same time. The cement slurry injection pressure is 2~3MPa, and the slurry water-cement ratio is 0.5.

[0022] The cement parameter of the cement mixing pile in the step S2 is not less than 15%.

[0023] In the step S3, a static pressure micro-disturbance construction process is used when sinking the H-shaped steel piles, the plane allowable deviation is ±20mm, and the elevation error is not more than 100mm.

[0024] In the step S7, low-strength concrete or foamed concrete is used to backfill environmentally sensitive areas during foundation pit backfilling.

[0025] The beneficial effects of the present invention are as follows: the double-row HU construction pile retaining structure of the present invention is composed of two parallel rows of HU construction piles, prefabricated assembled crown beams, connecting beams and other main components, which enhances the overall stability and bearing capacity of the structure, and has the advantages of good water-stopping effect, flexible and fast construction, and economy and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a cross-sectional schematic diagram of the double-row HU construction method pile enclosure structure of the present invention;

[0027] Figure 2 It is a schematic plan view of the double-row HU construction method pile enclosure structure of the present invention;

[0028] Figure 3 This is a front view of the outer side steel plate of the crown beam of the present invention;

[0029] Figure 4 A top view of the outer side steel plate of the crown beam of the present invention;

[0030] Figure 5 This is a front view of the inner steel plate of the crown beam and the connecting beam module of the present invention;

[0031] Figure 6 It is a top view of the inner steel plate of the crown beam and the connecting beam module of the present invention;

[0032] In the figure: 1-H-shaped steel pile; 2-U-shaped steel sheet pile; 3-outer steel plate of crown beam; 31-outer steel plate tie rod hole; 32-outer steel plate longitudinal connecting plate of crown beam; 4-inner steel plate of crown beam and connecting beam module; 41-inner steel plate tie rod hole; 42-inner steel plate longitudinal connecting plate of crown beam; 43-connecting beam; 44-inner steel plate of crown beam; 5-soil in passive zone of foundation pit; 6-soil between piles; 7-foundation structure bottom plate; 8-plain concrete; 9-tie rod; 10-bolt;

[0033] The following is a detailed description of the embodiments of the invention with reference to the accompanying drawings. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0035] like Figure 1-Figure 6As shown, a modular assembled double-row HU construction method pile support structure includes two parallel rows of HU construction method piles, each row of HU construction method piles consists of H-shaped steel piles 1 and U-shaped steel sheet piles 2, the U-shaped steel sheet piles 2 are interlocked with each other through locking joints to form a continuous steel sheet pile wall, the H-shaped steel piles 1 are inserted between the steel sheet pile walls formed by the U-shaped steel sheet piles 2, a crown beam outer steel plate 3 is arranged on the outer side of the top of the H-shaped steel piles 1, and a crown beam inner steel plate and a connecting beam module 4 are arranged on the inner side of the top of the front and rear rows of H-shaped steel piles 1. Biaxial or triaxial cement mixing piles are used to reinforce the soil between the piles 6 of the double-row steel sheet pile wall and the soil 5 in the passive zone of the foundation pit, the soil between the piles 6 is reinforced to the ground, the soil 5 in the passive zone of the foundation pit is reinforced to the bottom plate 7 of the foundation structure, and plain concrete 8 is used to backfill the bottom plate 7 of the foundation structure and the surrounding structure.

[0036] The crown beam inner steel plate and connecting beam module 4 includes a crown beam inner steel plate 44, a connecting beam 43, a crown beam inner steel plate longitudinal connecting plate 42 and an inner steel plate tie rod hole 41. The crown beam inner steel plate 44 and the connecting beam 43 are welded into an "I" shape. A plurality of inner steel plate tie rod holes 41 are opened on the crown beam inner steel plate 44. The two ends of the crown beam inner steel plate 44 are welded to opposite crown beam inner steel plate longitudinal connecting plates 42.

[0037] The outer steel plate 3 of the crown beam and the inner steel plate 44 of the crown beam are connected by a tie rod 9 , and the tie rod 9 is located in the gap between two adjacent H-shaped steel piles 1 .

[0038] A plurality of outer steel plate tie rod holes 31 are provided on the outer steel plate 3 of the crown beam, and longitudinal connecting plates 32 of the outer steel plate of the crown beam are provided at both ends of the outer steel plate 3 of the crown beam.

[0039] The inner crown beam steel plate longitudinal connecting plates 42 of the inner crown beam steel plate 44 and the outer crown beam steel plate longitudinal connecting plates 32 of the outer crown beam steel plate 3 are connected by bolts 10 .

[0040] A construction method of a modular assembled double-row HU construction method pile support structure, the steps of which are:

[0041] S1. Preliminary preparation: Complete the three connections and one leveling of the construction site to ensure that there are no obstacles in the construction area to facilitate the entry and exit of construction machinery and materials; conduct precise measurement and positioning to determine the position and elevation of the double-row steel sheet pile wall, and prepare the required H-shaped steel piles 1, U-shaped steel sheet piles 2, positioning frames and vibratory hammer construction materials and equipment;

[0042] S2. Cement mixing pile construction: Use biaxial or triaxial cement mixing piles to reinforce the soil between the piles 6 of the double-row steel sheet pile wall and the soil 5 in the passive area of ​​the foundation pit. The soil between the piles 6 is reinforced to the ground, and the soil 5 in the passive area of ​​the foundation pit is reinforced to the bottom plate 7 of the foundation structure. The cement parameter of the cement mixing piles shall not be less than 15%;

[0043] S3, HU construction method piles after construction: U-shaped steel sheet piles 2 are driven according to the design requirements, and they are interlocked with each other through the lock mouth to form a continuous steel sheet pile wall. The insertion depth of H-shaped steel piles 1 is determined according to the foundation pit depth and soil conditions. H-shaped steel piles 1 are inserted between the water stop walls formed by U-shaped steel sheet piles 2 according to the design requirements. The static pressure micro-disturbance construction process is adopted when sinking the H-shaped steel piles 1. The plane allowable deviation is ±20mm, and the elevation error is not more than 100mm;

[0044] S4. Construction of front row HU construction method piles: U-shaped steel sheet piles 2 are driven according to design requirements, and they are interlocked with each other through the lock. H-shaped steel piles 1 are inserted between the water stop walls formed by the U-shaped steel sheet piles 2 according to design requirements. The spacing is half of the spacing of the rear row H-shaped steel piles 1. The front and rear rows of U-shaped steel sheet piles 2 and H-shaped steel piles 1 must ensure flatness and verticality. Distortion is not allowed. Verticality must be ensured during insertion. If there are joints in the H-shaped steel piles 1, the bending, shear and tensile strength of the joints must be guaranteed. The joints should be located 2m above and below the excavation surface, and the joints of two adjacent H-shaped steel piles 1 should be staggered by more than 1m.

[0045] S5, prefabricated crown beam assembly: a crown beam outer steel plate 3 is arranged on the outer side of the top of the H-shaped steel pile 1, a crown beam inner steel plate and a connecting beam module 4 are arranged on the inner side of the top of the H-shaped steel pile 1, and the crown beam inner steel plates 44 of the front and rear rows of HU construction method piles are connected by a connecting beam 43, and the crown beam inner steel plates 44 and the connecting beam 43 are connected by welding; the crown beam outer steel plates 3 and the crown beam inner steel plates 44 are connected by a tie rod 9, and the tie rod 9 is located in the gap between two adjacent H-shaped steel piles 1; the crown beam inner steel plate longitudinal connecting plate 42 between the crown beam inner steel plates 44 and the crown beam outer steel plate longitudinal connecting plate 32 between the crown beam outer steel plates 3 are connected by bolts 10. After the pile top crown beam assembly is completed and accepted, the foundation pit excavation can be carried out immediately;

[0046] S6. Foundation construction of excavator: The excavation of foundation should be carried out in blocks. After the excavation reaches the bottom of the pit, the cushion layer should be constructed immediately. The excavated soil is strictly prohibited from being piled on the top of the slope. The overload value at the pit edge should be controlled not to exceed 20kPa. After the excavation is completed, the foundation project should be carried out as soon as possible. The base plate 7 and the surrounding structure should be filled with plain concrete 8, and the strength should be the same as the base plate of the foundation structure;

[0047] S7. Backfill of foundation pit: The backfill soil of foundation pit is backfilled in layers with silt sand and compacted with water. The backfill soil is 200~300mm above the ground.

[0048] S8. Recycling of related module components of double-row HU construction method piles: After the foundation pit backfill is compacted, the components are recycled. The static extraction process is used to first release the connection between the tie rod 9 and the bolt 10, recycle the prefabricated crown beam, then remove the H-shaped steel pile 1, and finally remove the U-shaped steel sheet pile 2. During the recycling process, pure cement slurry should be used for grouting at the same time. The cement slurry injection pressure is 2~3MPa, and the slurry water-cement ratio is 0.5.

[0049] In the description of the invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0051] In the invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be fixedly connected, detachably connected, or integrated; it can be mechanically connected, electrically connected, or able to communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0052] The invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the invention, or they are directly applied to other occasions without improvement, they are all within the scope of protection of the invention.

Claims

1. A modular assembled double-row HU construction method pile support structure, characterized in that: The invention comprises two parallel rows of HU construction method piles, each row of which is composed of H-shaped steel piles (1) and U-shaped steel sheet piles (2). The U-shaped steel sheet piles (2) are interlocked with each other through locking joints to form a continuous steel sheet pile wall. The H-shaped steel piles (1) are inserted between the steel sheet pile walls formed by the U-shaped steel sheet piles (2). A crown beam outer steel plate (3) is arranged on the outer side of the top of the H-shaped steel piles (1). A crown beam inner steel plate and a connecting beam module (4) are arranged on the inner side of the top of the front and rear rows of H-shaped steel piles (1). The soil between the piles (6) of the double-row steel sheet pile wall and the soil in the passive zone of the foundation pit (5) are reinforced by biaxial or triaxial cement mixing piles. The soil between the piles (6) is reinforced to the ground. The soil in the passive zone of the foundation pit (5) is reinforced to the bottom plate of the foundation structure (7). Plain concrete (8) is used to backfill the bottom plate of the foundation structure (7) and the surrounding structure.

2. A modular assembled double-row HU construction method pile support structure according to claim 1, characterized in that: The crown beam inner steel plate and connecting beam module (4) comprises a crown beam inner steel plate (44), a connecting beam (43), a crown beam inner steel plate longitudinal connecting plate (42) and an inner steel plate tie rod hole (41); the crown beam inner steel plate (44) and the connecting beam (43) are welded into an "I" shape; a plurality of inner steel plate tie rod holes (41) are provided on the crown beam inner steel plate (44); and opposite crown beam inner steel plate longitudinal connecting plates (42) are welded at both ends of the crown beam inner steel plate (44).

3. A modular assembled double-row HU construction method pile support structure according to claim 2, characterized in that: The outer steel plate (3) of the crown beam and the inner steel plate (44) of the crown beam are connected via a tie rod (9), and the tie rod (9) is located in the gap between two adjacent H-shaped steel piles (1).

4. The modular assembled double-row HU construction method pile support structure according to claim 3 is characterized in that: A plurality of outer steel plate tie rod holes (31) are provided on the outer steel plate (3) of the crown beam, and crown beam outer steel plate longitudinal connecting plates (32) are provided at both ends of the outer steel plate (3).

5. The modular assembled double-row HU construction pile support structure according to claim 4 is characterized in that: The inner crown beam steel plate longitudinal connecting plates (42) of the inner crown beam steel plate (44) and the outer crown beam steel plate longitudinal connecting plates (32) of the outer crown beam steel plate (3) are connected by bolts (10).

6. The construction method of a modular assembled double-row HU construction method pile support structure according to claim 5 is characterized in that: The steps are: S1. Preliminary preparation: Complete the three connections and one leveling of the construction site to ensure that there are no obstacles in the construction area to facilitate the entry and exit of construction machinery and materials; conduct precise measurement and positioning to determine the position and elevation of the double-row steel sheet pile wall, and prepare the required H-shaped steel piles (1), U-shaped steel sheet piles (2), positioning frames and vibratory hammer construction materials and equipment; S2. Cement mixing pile construction: biaxial or triaxial cement mixing piles are used to reinforce the soil between the piles (6) of the double-row steel sheet pile wall and the soil in the passive zone of the foundation pit (5). The soil between the piles (6) is reinforced to the ground, and the soil in the passive zone of the foundation pit (5) is reinforced to the bottom plate of the foundation structure (7). S3, after construction, HU construction method piles are installed: U-shaped steel sheet piles (2) are driven according to the design requirements, and they are interlocked with each other through the locking mouth to form a continuous steel sheet pile wall. The insertion depth of the H-shaped steel piles (1) is determined according to the foundation pit depth and soil conditions. The H-shaped steel piles (1) are inserted between the water stop walls formed by the U-shaped steel sheet piles (2) according to the design requirements; S4, construction of the front row HU construction method piles: U-shaped steel sheet piles (2) are driven in accordance with the design requirements, interlocked with each other through the locking mouth, and H-shaped steel piles (1) are inserted between the water stop walls formed by the U-shaped steel sheet piles (2) in accordance with the design requirements, and the spacing between them is half of the spacing of the rear row H-shaped steel piles (1); S5, assembly of prefabricated crown beams: a crown beam outer steel plate (3) is arranged on the outer side of the top of the H-shaped steel pile (1), a crown beam inner steel plate and a connecting beam module (4) are arranged on the inner side of the top of the H-shaped steel pile (1), the crown beam inner steel plates (44) of the front and rear rows of HU construction method piles are connected by a connecting beam (43), and the crown beam inner steel plates (44) and the connecting beam (43) are connected by welding; the crown beam outer steel plates (3) and the crown beam inner steel plates (44) are connected by a tie rod (9), and the tie rod (9) is located in the gap between two adjacent H-shaped steel piles (1); the crown beam inner steel plate longitudinal connecting plate (42) between the crown beam inner steel plates (44) and the crown beam outer steel plate longitudinal connecting plate (32) between the crown beam outer steel plates (3) are connected by bolts (10), and after the crown beam assembly on the pile top is completed and accepted, the foundation pit can be excavated immediately; S6. Foundation construction of excavator: The excavation of foundation pit should be carried out in blocks. After the excavation reaches the bottom of the pit, the cushion layer should be constructed immediately to seal the bottom. The excavated soil is strictly prohibited from being piled on the top of the slope. The overload value at the pit edge should be controlled not to exceed 20 kPa. After the excavation is completed, the foundation engineering should be carried out as soon as possible. The space between the foundation structure bottom plate (7) and the surrounding structure should be filled with plain concrete (8), and the strength should be the same as that of the foundation structure bottom plate. S7. Backfill of foundation pit: The backfill soil of foundation pit is backfilled in layers with silt sand and compacted with water. The backfill soil is 200~300mm above the ground. S8. Recycling of related module components of double-row HU construction method piles: After the foundation pit backfill is compacted, the components are recycled. The static extraction process is used to first release the connection between the tie rod (9) and the bolt (10), recycle the prefabricated crown beam, then remove the H-shaped steel pile (1), and finally remove the U-shaped steel sheet pile (2). During the recycling process, pure cement slurry should be used for grouting. The cement slurry injection pressure is 2~3MPa, and the slurry water-cement ratio is 0.

5.

7. The construction method of a modular assembled double-row HU construction method pile support structure according to claim 6 is characterized in that: The cement parameter of the cement mixing pile in the step S2 is not less than 15%.

8. The construction method of a modular assembled double-row HU construction method pile support structure according to claim 7 is characterized in that: In the above-mentioned step S3, the H-shaped steel pile (1) is sunk by adopting a static pressure micro-disturbance construction process, the plane allowable deviation is ±20 mm, and the elevation error is not greater than 100 mm.

9. The construction method of a modular assembled double-row HU construction method pile support structure according to claim 8 is characterized in that: In the step S7, low-strength concrete or foamed concrete is used to backfill environmentally sensitive areas during foundation pit backfilling.

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