A pile wall foundation structure and construction method suitable for soft soil sites

Abstract

The application provides a pile wall foundation structure suitable for soft soil sites and a construction method thereof. The foundation structure comprises a bearing platform, a column and at least two groups of pile wall foundations. Each group of pile wall foundations is a pile wall structure formed by placing a pile wall reinforcement cage in a foundation groove and then pouring concrete. The pile wall reinforcement cage comprises an outer reinforcement cage frame and a plurality of circular pile reinforcement cages. The outer reinforcement cage frame is a frame structure composed of vertical and horizontal reinforcements. The plurality of circular pile reinforcement cages are dispersedly arranged in the outer reinforcement cage frame, and a reinforcement framework is arranged in each circular pile reinforcement cage. The pile wall foundation is constructed by first constructing a guide wall groove, preparing mud, pouring the mud into the groove, then excavating the pile wall construction groove in sections to the designed width and depth, placing the pile wall reinforcement cage and pouring the concrete. The pile wall foundation has a large width, improves the vertical bearing capacity and horizontal force resistance of the foundation, has good integrity, is superior to a foundation structure composed of a plurality of foundation piles and is simple and convenient to construct.

Description

Technical Field

[0001] This invention relates to the field of building foundation design and construction, specifically a pile wall foundation structure and construction method suitable for soft soil sites. Background Technology

[0002] With the rapid and high-quality development of the national economy, the construction industry has gained increasing importance in my country's national economy. There is a growing number of super high-rise and long-span buildings and structures. These buildings and structures have high requirements for foundation engineering; therefore, foundation engineering needs to address the issues of foundation strength, deformation, and stability.

[0003] Due to increasingly stringent environmental protection requirements, some industrial enterprises are no longer permitted to set up large material yards in the open air, and instead require the erection of sheds to prevent dust pollution. Both the load from the stockpiled materials and the load from the sheds generate significant horizontal forces. Under the influence of these horizontal forces, the foundation continuously shifts outwards, gradually causing the columns to tilt, sometimes exceeding the required specifications. This is particularly pronounced on soft soil sites, posing significant safety hazards and impacting production operations.

[0004] Currently, commonly used foundation types for buildings include natural foundations, composite foundations, and pile foundations. Numerous experts and scholars have conducted extensive research on foundation combinations and building materials, yielding considerable results. Liu Pengtang et al. disclosed a high-bearing-capacity building foundation pile, which improves the pile's bearing capacity by setting triangular and circular fixing blocks, but the construction is overly cumbersome. Luo Weishi et al. disclosed a soft-soil foundation structure primarily addressing building settlement issues, but it cannot solve displacement caused by horizontal forces. Zhang Liying et al. disclosed a combined steel sheet pile and diaphragm wall cylindrical foundation structure and construction method, suitable for wind turbine foundations, involving multiple processes such as cement-soil mixing, steel sheet pile construction, and diaphragm wall construction, making it overly complex.

[0005] To address deformation caused by horizontal forces, engineering practices typically involve increasing the number of engineering piles. However, this method offers only a limited increase in horizontal force, resulting in minimal effectiveness, significantly increased project costs, and longer construction periods, making it neither economical nor reliable. Due to the complex influence of factors such as structural form, geological conditions, and construction environment, this paper proposes a foundation structure and construction method that is simple to implement, highly efficient, safe, and reliable, possessing broad application and economic value. Summary of the Invention

[0006] This invention addresses the problems of easy deformation and poor stability of existing foundations in soft soil sites by providing a pile wall foundation structure and construction method suitable for soft soil sites. The foundation structure has good integrity and can improve the vertical bearing capacity and resistance to horizontal forces compared with ordinary pile foundations. It is safe, reliable and economical.

[0007] To achieve the above-mentioned technical objectives, the present invention provides a pile wall foundation structure suitable for soft soil sites. The foundation structure includes a pile cap, at least two sets of pile wall foundations placed below the pile cap, and columns placed on top of the pile cap. The columns, the pile cap, and the pile wall are integrated. Each set of pile wall foundations is a pile wall structure formed by directly placing a pile wall reinforcement cage in a trench in the foundation and then pouring concrete. The pile wall reinforcement cage includes an outer frame and multiple circular pile reinforcement cages placed inside the outer frame. The outer frame is a frame structure composed of vertical and horizontal reinforcement bars welded together. The multiple circular pile reinforcement cages are dispersedly arranged inside the outer frame and welded together with it. A reinforcement skeleton is provided inside each circular pile reinforcement cage, and the reinforcement skeleton is welded inside the circular pile reinforcement cage.

[0008] The preferred technical solution of the present invention is as follows: the reinforcing steel cage includes two parallel longitudinal reinforcing bars and a supporting reinforcing bar placed between the two longitudinal reinforcing bars. The supporting reinforcing bar is bent into a trapezoidal shape and welded to the two longitudinal reinforcing bars. The length of the reinforcing steel cage is the same as the length of the circular pile reinforcing cage and is welded to the circular pile reinforcing cage as a whole.

[0009] The preferred technical solution of the present invention is as follows: the circular pile reinforcement cage includes vertical main bars, horizontal reinforcing bars and spiral bars, and the bars are welded together at the intersections.

[0010] The preferred technical solution of the present invention is as follows: the outer frame of the reinforcing cage is a square reinforcing mesh composed of vertical and horizontal reinforcing bars welded together, which is placed around the circular pile reinforcing cage. The distance between the vertical and horizontal reinforcing bars of the outer frame of the reinforcing cage is 200~400mm, and the diameter is not less than 14mm. The number of circular pile reinforcing cages is 2~5, which are equidistantly arranged in the outer frame of the reinforcing cage.

[0011] The preferred technical solution of the present invention is as follows: the cross-section of the pile wall foundation is rectangular, the width can be 3m~6m, and the thickness is 0.6~1.2m; the diameter of the circular pile reinforcement cage is less than 100mm compared with the thickness of the pile wall foundation; the bottom of the pile wall foundation should be embedded in rock for not less than 3 times the thickness of the pile wall foundation, and not less than 3m.

[0012] The preferred technical solution of the present invention is that the supporting steel bars of the skeleton are bent into an isosceles trapezoid with a 60° angle.

[0013] The present invention also provides a construction method for the above-mentioned pile wall foundation structure suitable for soft soil sites:

[0014] (1) First, conduct surveying and setting out to locate the position of each pile wall foundation, and mark the position of the pile wall foundation construction trench and guide wall on the ground with lime;

[0015] (2) Excavate the guide wall trench, construct the guide wall, and prepare mud slurry. Pour the mud slurry into the guide wall trench. During the construction of the pile wall, keep the mud slurry height more than 1m above the bottom of the guide wall.

[0016] (3) The pile driver is in place, and the pile wall foundation construction trench is excavated in sections in the guide wall trench to the designed width and depth;

[0017] (4) The first mud replacement is prepared to lift and put the pile wall reinforcement cage. The pile wall reinforcement cage is put into the pile wall foundation construction trench as a whole. The pile wall reinforcement cage includes a reinforcement cage outer frame that matches the pile wall foundation construction trench and 2 to 5 circular pile reinforcement cages placed in the reinforcement cage outer frame.

[0018] (5) After the pile wall reinforcement cage is lowered into place, a second mud replacement is carried out. After the design and specification requirements are met, the concrete guide pipe is lowered and concrete is poured into the pile wall foundation construction trench. When the concrete is poured, the mud is discharged from the mud discharge port. The concrete is poured to the design elevation to complete the construction of the reorganized pile wall foundation.

[0019] (6) Move the machine to the next pile wall foundation construction position and repeat steps (2) to (5) to complete the construction of all pile wall foundations;

[0020] (7) Construct the foundation. The top of each pile wall foundation is embedded in the foundation by 100~150mm. The steel bars at the top of the pile wall foundation extend into the foundation, and the steel bars extending into the foundation are inclined outward by 5~8°. After the foundation is constructed, columns are constructed on the upper part of the foundation.

[0021] The preferred technical solution of the present invention is as follows: in step (2), the guide wall adopts a reinforced concrete structure or a steel structure, and the distance between the inner edge of the guide wall on each side and the outer edge of the pile wall foundation is greater than 25~50mm; the guide wall is set with a working width of 0.8~1.0m on the ground and its insertion depth into the ground is 1.5~3m.

[0022] The preferred technical solution of the present invention is as follows: In step (3), the pile wall foundation construction trench is divided into two or three sections. When the trench is divided into three sections, the two sides are constructed first and the middle is constructed later. During excavation, the mud height is always kept more than 1m higher than the bottom of the guide wall.

[0023] The preferred technical solution of the present invention is as follows: when constructing the next set of pile wall foundations in step (6), the distance between two adjacent sets of pile wall foundations shall not be less than three times the thickness of the pile wall foundation, and the long side of each set of pile wall foundations shall be parallel to the direction of the horizontal force; when constructing the pile cap in step (7), the distance between the edge of the pile wall foundation and the outer edge of the pile cap shall not be less than 150mm.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) The pile foundation of the present invention adopts at least two sets of pile walls. The width of the pile wall is larger than that of the pile body, which improves the vertical bearing capacity and horizontal resistance of the foundation. It has good integrity and is suitable for soft soil sites.

[0026] (2) The pile wall in this invention is formed by directly excavating trenches, installing pile wall steel cages, and pouring concrete. Its construction process is simple, safe, economical, and efficient, and has a wide range of application prospects.

[0027] (3) The pile wall reinforcement cage in this invention includes multiple circular reinforcement cages. Each circular reinforcement cage has a steel reinforcement skeleton in the middle. The multiple circular reinforcement cages are connected together by transverse and longitudinal reinforcement bars, which facilitates concrete pouring and increases the strength and stability of the pile foundation. Attached Figure Description

[0028] Figure 1 This is a plan view of the pile wall foundation structure in this invention;

[0029] Figure 2 yes Figure 1 Sectional view of AA in the middle;

[0030] Figure 3 yes Figure 2 Cross-sectional view of the middle section (BB);

[0031] Figure 4 yes Figure 3 CC section view;

[0032] Figure 5 This is a schematic diagram of the steel reinforcement cage in this invention;

[0033] Figure 6 This is a schematic diagram of the circular pile reinforcement cage in this invention;

[0034] Figure 7 yes Figure 6 Cross-sectional view of DD in the middle;

[0035] Figure 8 This is a schematic diagram of the guide wall during the construction process of this invention;

[0036] Figure 9 yes Figure 8 EE cross-section;

[0037] Figure 10 This is a schematic diagram illustrating the sequence of three excavations of the pile wall during the construction process of this invention;

[0038] Figure 11 yes Figure 10 Cross-sectional view of the EE.

[0039] In the diagram: 1-Pile cap; 2-Pile wall foundation; 3-Column; 4-Reinforcing steel cage; 400-Longitudinal reinforcement of the cage; 401-Supporting reinforcement of the cage; 5-Circular pile reinforcement cage; 500-Vertical main reinforcement; 501-Horizontal reinforcement; 502-Helical reinforcement; 6-Outer frame of the reinforcement cage; 7-Guide wall; 8-Concrete; 9-Mud; 10-Mud discharge port; 11-Concrete guide pipe; 12-Pile wall reinforcement. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments. Figures 1 to 11 All accompanying drawings are simplified versions of embodiments and are intended only to clearly and concisely illustrate the embodiments of the present invention. The technical solutions shown in the drawings below are specific solutions of embodiments of the present invention and are not intended to limit the scope of the claimed invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0041] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] The embodiment provides a pile wall foundation structure suitable for soft soil sites, such as Figures 1 to 7 As shown, the foundation structure includes a pile cap 1, at least two sets of pile wall foundations 2 placed below the pile cap 1, and columns 3 placed on top of the pile cap 1. The columns 3, the pile cap 1, and the pile wall foundations 2 are integrated. Each set of pile wall foundations 2 is a pile wall structure formed by directly placing a pile wall reinforcement cage in a trench in the foundation and then pouring concrete. The pile wall reinforcement cage includes an outer frame 6 and multiple circular pile reinforcement cages 5 placed inside the outer frame 6. The cross-section of the pile wall foundation 2 is rectangular, with a width of 3m to 6m and a thickness of 0.6m to 1.2m. The diameter of the circular pile reinforcement cages 5 is less than 100mm compared to the thickness of the pile wall foundation 2. The bottom of the pile wall foundation 2 should be embedded in rock for a distance of not less than 3 times the thickness of the pile wall foundation 2 and not less than 3m.

[0043] The embodiment provides a pile wall foundation structure suitable for soft soil sites, such as Figure 4As shown, the outer frame 6 of the reinforcing cage is a frame structure welded from vertical and horizontal reinforcing bars. The outer frame 6 is a square reinforcing mesh formed by the cross-welding of vertical and horizontal reinforcing bars, placed around the circular pile reinforcing cage 5. The spacing between the vertical and horizontal reinforcing bars of the outer frame 6 is 200-400mm, and the diameter is not less than 14mm. There are 2-5 circular pile reinforcing cages 5, equidistantly arranged on the outer frame 6 and welded together. Each circular pile reinforcing cage 5 contains a reinforcing skeleton 4, which is welded inside the circular pile reinforcing cage 5. Figure 5 As shown, the reinforcing steel cage 4 includes two parallel longitudinal reinforcing bars 400 and a supporting reinforcing bar 401 placed between the two longitudinal reinforcing bars 400. The supporting reinforcing bar 401 is bent into an isosceles trapezoid at a 60-degree angle and welded to the two longitudinal reinforcing bars 400 as a whole. The length of the reinforcing steel cage 4 is the same as the length of the circular pile reinforcing cage 5, and it is welded to the circular pile reinforcing cage 5 as a whole. Figure 6 and Figure 7 As shown, the circular pile reinforcement cage 5 includes vertical main bars 500, horizontal reinforcing bars 501 and spiral bars 502, which are welded together at the intersection of the bars.

[0044] The invention will be further described below with reference to specific embodiments, which are applied to the foundation of a shed in a large metallurgical quarry in southwestern coastal my country. The site strata for this construction project, from top to bottom, consist of: cohesive fill, gravelly fill, dredged silt, dredged fine sand, fine sand, silty clay, gravelly cohesive soil, strongly weathered argillaceous siltstone, and moderately weathered argillaceous siltstone. After foundation treatment, a shed is constructed and stocked with ore powder. The shed is 840m long, 96m span, and has a maximum height of 45m. The roof is a grid structure with corrugated steel roof tiles. The ore powder is stocked inside the shed in a trapezoidal pattern, with a designed maximum height of 14m. The density of the ore is 23~28kN / m³, and the angle of repose is 36°~41°.

[0045] Due to the presence of thick soft soil and limited lateral restraint at the site, the foundation will experience significant horizontal displacement under the horizontal loads of the space frame and material stockpiles. Calculations are difficult to perform to meet the required specifications, and existing ordinary pile foundations cannot meet the load-bearing requirements. During testing, excessive horizontal displacement and significant deviation of the pre-embedded points from their design positions resulted in the inability to install the superstructure. To control the horizontal displacement of the foundation in this area and ensure the required horizontal bearing capacity, the inventors of this application have adopted the pile-wall foundation structure described in this application. The specific design, construction, and testing technical requirements are as follows:

[0046] (1) Based on the geological conditions and the magnitude of the structural stress, the spacing of the pile wall foundation is calculated to be 4.5m, the size of the pile wall foundation is 5×0.8m, and the pile wall between adjacent columns is 5×0.6m; a strip pile cap with a thickness of 1.2m is adopted; the design vertical bearing capacity is 10000kN and the horizontal bearing capacity is 2800kN; the design strength grade of the pile wall concrete is C40, and the filling coefficient during concrete pouring is greater than 1; the thickness of the protective layer of the vertical main reinforcement of the pile wall is 50mm. The construction should ensure that the pile tip completely penetrates the weak layer and is embedded in the intact supporting rock, so that the depth of the pile tip into the moderately weathered siltstone is not less than 3 meters.

[0047] (2) Fabricate the pile wall reinforcement according to the design drawings; the ratio of the measured tensile strength to the measured yield strength of the reinforcement in the pile wall foundation shall not be less than 1.25, and the ratio of the measured yield strength to the standard strength value of the reinforcement shall not be greater than 1.3.

[0048] (3) Conduct surveying and setting out to locate the position of each pile wall foundation, and mark the position of the pile foundation construction trench and guide wall trench on the ground with lime.

[0049] (4) Excavate the guide wall trench and construct the guide wall; the guide wall shall be made of reinforced concrete or steel, and the distance between the inner edge of each guide wall and the outer edge of the pile wall foundation shall be greater than 25~50mm; the guide wall shall have a working width of 0.8~1.0m on the ground, and its insertion depth into the ground shall be determined according to the site conditions, which may be 1.5~3m. Prepare mud slurry and pour it into the trench of the guide wall. During the construction of the pile wall, keep the mud slurry height at least 1m above the bottom of the guide wall.

[0050] (5) The pile driver is in place and the excavation is carried out in sections to the designed width and depth. The construction trench for the pile wall foundation is divided into three sections, as shown in 10. The two sides are constructed first and then the middle is constructed. During excavation, the mud height is always kept more than 1m above the bottom of the guide wall.

[0051] (6) During the first mud replacement, prepare to lift and place the pile wall reinforcement cage. The entire pile wall reinforcement cage is placed into the pile wall foundation construction trench. The pile wall reinforcement cage includes an outer frame of the reinforcement cage that matches the pile wall foundation construction trench and 2 to 5 circular pile reinforcement cages placed inside the outer frame. The construction unit should ensure the integrity of the pile wall reinforcement cage during hoisting and sinking. The main reinforcement bars and horizontal reinforcement bars of the pile wall foundation are welded to form a reinforcement cage skeleton. The reinforcement cage should be properly placed. The reinforcement cage should be vertical throughout the entire process of entering the hole to prevent bending deformation. Protective layer pads should be provided. If obstruction is encountered, it should not be lowered. Measures should be taken to ensure that the thickness of the protective layer and the bottom elevation of the cage are within the allowable error range. To ensure the thickness of the protective layer, protective iron should be installed on both sides of the pile wall, with a vertical spacing of 4-5 meters.

[0052] (7) After the pile wall reinforcement cage is lowered into place, a second mud replacement is carried out. After the design and specification requirements are met, the concrete guide pipe is lowered and concrete is poured into the pile wall foundation construction trench. When the concrete is poured, the mud is discharged from the mud discharge port and poured to the design elevation to complete the construction of the reorganized pile wall foundation.

[0053] (8) Move the machine to the next pile wall foundation construction position and repeat steps (2) to (5) to complete the construction of all pile wall foundations; when constructing the next pile wall foundation, the distance between two adjacent pile wall foundations shall not be less than three times the thickness of the pile wall foundation, and the long side of each pile wall foundation shall be parallel to the direction of the horizontal force.

[0054] (9) Clean the top of the pile wall and pour the pile cap. The top of each pile wall foundation is embedded in the pile cap by 100~150mm. The steel bars at the top of the pile wall foundation extend into the pile cap, and the pile wall steel bars 12 extending into the pile cap are inclined outward by 5~8°. After the pile cap is constructed, columns are constructed on the top of the pile cap. The construction method of the pile cap and columns is the same as the construction process of the existing pile foundation pile cap and columns. When constructing the pile cap, the distance between the edge of the pile wall foundation and the outer edge of the pile cap is not less than 150mm.

[0055] During the construction of the pile wall foundation in this embodiment, testing elements such as steel stress gauges and inclinometers should be installed at appropriate locations. The monitoring unit should also take necessary measures to protect these testing elements and ensure their survival rate.

[0056] After the pile wall foundation construction in the embodiment was completed, ultrasonic testing was used to inspect the quality of the concrete in 20% of all pile walls; core drilling was used to test the quality and strength of the concrete in the pile walls, with the number of tests not less than 10% of the total number of piles, and not less than 10 piles; and static load tests were conducted at 3 points to assess horizontal bearing capacity. All tests showed that the results met or exceeded Class II standards, satisfying the design requirements, with over 90% of the pile walls meeting Class I standards; the horizontal bearing capacity also met the design requirements.

[0057] The above description is merely one embodiment of the present invention, and while it is detailed and specific, it should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A pile wall foundation structure suitable for soft soil sites, characterized in that: The basic structure includes a foundation (1), at least two sets of pile wall foundations (2) placed below the foundation (1), and a column (3) placed on top of the foundation (1). The column (3), the foundation (1), and the pile wall foundation (2) are connected as one unit. Each set of pile wall foundations (2) is a pile wall structure formed by directly placing the pile wall reinforcement cage in the foundation trench and then pouring concrete. The pile wall reinforcement cage includes a reinforcement cage outer frame (6) and multiple circular pile reinforcement cages (5) placed inside the reinforcement cage outer frame (6). The reinforcement cage outer frame (6) is a frame structure composed of vertical and horizontal reinforcement welded together. Multiple circular pile reinforcement cages (5) are dispersed inside the reinforcement cage outer frame (6) and welded together with the reinforcement cage outer frame (6). A reinforcement skeleton (4) is provided inside each circular pile reinforcement cage (5). The reinforcement skeleton (4) is welded inside the circular pile reinforcement cage (5). The steel reinforcement cage (4) includes two parallel longitudinal steel bars (400) and a support steel bar (401) placed between the two longitudinal steel bars (400). The support steel bar (401) is bent into a trapezoidal shape and welded to the two longitudinal steel bars (400) as a whole. The length of the steel reinforcement cage (4) is the same as the length of the circular pile steel reinforcement cage (5) and is welded to the circular pile steel reinforcement cage (5) as a whole. The outer frame (6) of the steel reinforcement cage is a square steel mesh composed of vertical steel bars and horizontal steel bars welded together. It is placed around the circular pile steel reinforcement cage (5). The distance between the vertical steel bars and the horizontal steel bars of the outer frame (6) of the steel reinforcement cage is 200~400mm and the diameter is not less than 14mm. There are 2~5 circular pile steel reinforcement cages (5) and they are equidistantly arranged in the outer frame (6) of the steel reinforcement cage.

2. The pile wall foundation structure suitable for soft soil sites according to claim 1, characterized in that: The circular pile reinforcement cage (5) includes vertical main bars (500), horizontal reinforcing bars (501) and spiral bars (502), which are welded together at the intersection of the bars.

3. A pile wall foundation structure suitable for soft soil sites according to claim 1, characterized in that: The cross-section of the pile wall foundation (2) is rectangular, with a width of 3m to 6m and a thickness of 0.6 to 1.2m; the diameter of the circular pile reinforcement cage (5) is 100mm smaller than the thickness of the pile wall foundation (2); the bottom of the pile wall foundation (2) should be embedded in rock for no less than 3 times the thickness of the pile wall foundation (2) and no less than 3m.

4. A pile wall foundation structure suitable for soft soil sites according to claim 1, characterized in that: The supporting steel bars (401) of the skeleton are bent into an isosceles trapezoid with a 60° angle.

5. A construction method for a pile wall foundation structure suitable for soft soil sites as described in any one of claims 1 to 4, characterized in that, The specific steps are as follows: (1) First, conduct surveying and setting out to locate the position of each pile wall foundation, and mark the position of the pile wall foundation construction trench and guide wall on the ground with lime; (2) Excavate the guide wall trench, construct the guide wall, and prepare mud slurry. Pour the mud slurry into the guide wall trench. During the construction of the pile wall, keep the mud slurry height more than 1m above the bottom of the guide wall. In step (2), the guide wall adopts a reinforced concrete structure or a steel structure. The distance between the inner edge of each guide wall and the outer edge of the pile wall foundation is greater than 25~50mm. The guide wall is set with a working width of 0.8~1.0m on the ground and its insertion depth into the ground is 1.5~3m. (3) The pile driver is in place, and the pile wall foundation construction trench is excavated in sections in the guide wall trench to the designed width and depth; (4) The first mud replacement is prepared to lift and put the pile wall reinforcement cage. The pile wall reinforcement cage is put into the pile wall foundation construction trench as a whole. The pile wall reinforcement cage includes a reinforcement cage outer frame that matches the pile wall foundation construction trench and 2 to 5 circular pile reinforcement cages placed in the reinforcement cage outer frame. (5) After the pile wall reinforcement cage is lowered into place, a second mud replacement is carried out. After the design and specification requirements are met, the concrete guide pipe is lowered and concrete is poured into the pile wall foundation construction trench. When the concrete is poured, the mud is discharged from the mud discharge port. The concrete is poured to the design elevation to complete the construction of the pile wall foundation. (6) Move the machine to the next pile wall foundation construction position and repeat steps (2) to (5) to complete the construction of all pile wall foundations; (7) Construct the foundation. The top of each pile wall foundation is embedded in the foundation by 100~150mm. The steel bars at the top of the pile wall foundation extend into the foundation, and the steel bars extending into the foundation are inclined outward by 5~8°. After the foundation is constructed, columns are constructed on the upper part of the foundation.

6. A construction method for a pile wall foundation structure suitable for soft soil sites according to claim 5, characterized in that: In step (3), the pile wall foundation construction trench is divided into two or three sections. When the trench is divided into three sections, the two sides are constructed first and the middle is constructed later. During excavation, the mud height is always kept more than 1m above the bottom of the guide wall.

7. A construction method for a pile wall foundation structure suitable for soft soil sites according to claim 5, characterized in that: In step (6), when constructing the next set of pile wall foundations, the distance between two adjacent sets of pile wall foundations shall not be less than three times the thickness of the pile wall foundation, and the long side of each set of pile wall foundations shall be parallel to the direction of the horizontal force; in step (7), when constructing the pile cap, the distance between the edge of the pile wall foundation and the outer edge of the pile cap shall not be less than 150mm.

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