Composite pile structure capable of weakening the influence of negative skin friction and construction method thereof

Abstract

The application discloses a composite pile structure capable of weakening the influence of negative friction resistance and a construction method, solves the problem of the composite pile structure being affected by negative friction resistance in the prior art, has the beneficial effect of effectively transferring the negative friction resistance borne by the pile body, and specifically has the following beneficial effect: a composite pile structure capable of weakening the influence of negative friction resistance, which comprises a cast-in-place pile, the top of the cast-in-place pile is connected with a prefabricated pile, the prefabricated pile is circumferentially sleeved with a first component in the form of a ring, at least one first recess is arranged on the outer surface of the prefabricated pile, each first recess is provided with a first tooth-shaped track, the first tooth-shaped track is arranged along the height direction of the prefabricated pile, the inner surface of the first component is provided with a second recess, the second recess is provided with a second tooth-shaped track, the first tooth-shaped track and the second tooth-shaped track are oppositely arranged, a plurality of tooth-shaped components are supported in the gap between the first tooth-shaped track and the second tooth-shaped track, and the prefabricated pile movably supports the tooth-shaped components.

Description

Technical Field

[0001] This invention relates to the field of pile foundations in building engineering, and in particular to a composite pile structure and construction method that can reduce the influence of negative skin friction. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Pile foundations, as a commonly used foundation structure in underground engineering, typically face various geological environments. In deep fill sites, the fill is often difficult to compact, leading to consolidation settlement. This consolidation results in significant negative skin friction on the pile foundation, reducing its bearing capacity. Therefore, reducing the negative skin friction of the fill strata on the pile foundation is crucial for the safety of both the pile foundation and the superstructure.

[0004] To reduce the impact of backfill consolidation, existing technologies disclose composite pile structures that reduce the negative skin friction of pile foundations. These devices have inner and outer sleeves on the pile foundation, and the relative sliding of the sleeves reduces the impact of backfill consolidation on the pile body.

[0005] The inventors discovered that the above method is not effective in reducing negative skin friction, which affects the stability of the pile foundation. Furthermore, after the pile is put into use, the sleeve and the pile are still separated, the sleeve will continue to settle, and the friction between the inner and outer sleeves will still act on the pile, which can easily cause the pile foundation to settle, affecting the stability of the building and being detrimental to the long-term performance of the pile foundation. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a composite pile structure that can reduce the influence of negative skin friction and effectively reduce the impact of soil consolidation on pile settlement.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: A composite pile structure capable of reducing the impact of negative skin friction includes a cast-in-place pile, a precast pile connected to the top of the cast-in-place pile, a first annular component circumferentially fitted around the precast pile, at least one first recess on the outer surface of the precast pile, each first recess having a first toothed track arranged along the height direction of the precast pile, a second recess on the inner surface of the first component, a second toothed track arranged within the second recess, the first toothed track and the second toothed track being arranged opposite to each other, the first toothed track and the second toothed track fitting together to support several toothed components, the precast pile movably supporting the toothed components, the toothed components being rotatable relative to the precast pile, and the negative skin friction experienced by the first component being transmitted to the precast pile through the toothed components.

[0008] As described above, in the composite pile structure, the cast-in-place piles and precast piles are connected. The positive skin friction of the bearing soil layer of the cast-in-place piles can partially offset the negative skin friction of the upper half of the pile body. The precast piles are circumferentially equipped with a first component, and the two are connected by a first toothed track and a second toothed track to support the toothed component, realizing a staggered power transmission mode. The rotational effect of the toothed component is used to convert the negative skin friction of the pile side generated by soil consolidation into the upward supporting force of the precast piles and cast-in-place piles, further reducing the negative skin friction and ensuring the reliability and long-term performance of the composite pile structure.

[0009] As described above, in a composite pile structure that can reduce the influence of negative skin friction, the length of the first toothed track is the same as the length of the first recess, and one end of the first toothed track is located at the top of the precast pile. The length of the first recess is less than the height of the precast pile, which can effectively prevent the toothed component from coming off the first toothed track; The precast pile has multiple first recesses on its outer surface. These first recesses are evenly distributed on the outer surface of the precast pile to ensure that the precast pile is subjected to uniform stress and that the settlement around the precast pile is also relatively uniform.

[0010] As described above, in a composite pile structure that can reduce the influence of negative skin friction, the length of the second toothed track is the same as the length of the second recess, and one end of the second toothed track is located at the top of the first member. The length of the second recess is less than the height of the first component.

[0011] As described above, in a composite pile structure that can reduce the influence of negative skin friction, when the precast pile is a solid precast pile, several first grouting pipes are pre-embedded in the height direction of the precast pile. The first grouting pipes are pre-set during the precast pile forming process to facilitate subsequent grouting. The first grouting pipe is provided with multiple first outlets. Some of the first outlets are located at the bottom of the precast pile, and some of the first outlets are located on both sides of the bottom of the precast pile. The first grouting pipe, through the provision of multiple first outlets, is used to fill the gaps generated by the splicing of the precast pile and the cast-in-place pile after the composite pile structure is spliced, thereby improving the overall integrity and preventing the generation of stress weak areas.

[0012] As described above, in a composite pile structure that can reduce the influence of negative skin friction, when the precast pile is a ring-shaped precast pile, a plurality of first grouting pipes are provided on the inner side of the precast pile, and the first grouting pipes can be placed in the hollow part of the ring-shaped precast pile. The first grouting pipe is provided with multiple first outlets. Some of the first outlets are located at the bottom of the precast pile, some of the first outlets are located on both sides of the bottom of the precast pile, and some of the first outlets are set along the height direction of the precast pile.

[0013] As described above, a composite pile structure that can reduce the influence of negative skin friction has a plurality of third recesses provided on the inner surface of the first component, and a second grouting pipe is inserted into the third recesses to inject grout into the space between the precast pile and the first component through the second grouting pipe. Along the height direction of the first component, the second grouting pipe is provided with multiple second outlets.

[0014] As described above, a composite pile structure that can reduce the influence of negative skin friction includes a first component comprising multiple metal plates assembled into a ring-shaped first component, which facilitates the transportation of the first component and also facilitates on-site construction. The height of the first component is lower than the height of the precast pile, which facilitates the connection between the bottom end of the precast pile and the top end of the cast-in-place pile.

[0015] As described above, a composite pile structure that can reduce the influence of negative skin friction has a circumferentially arranged casing at the top of the cast-in-place pile, and the bottom end of the precast pile is inserted into the casing and welded to the reinforcing steel at the top of the cast-in-place pile. The bottom end of the first component is spaced apart from the top end of the casing, thus leaving space between the bottom end of the first component and the casing, providing space for the first component to settle relative to the precast pile.

[0016] As described above, in a composite pile structure that can reduce the influence of negative skin friction, the toothed component is a toothed roller, which is installed on a connecting shaft. The precast pile has opening slots on both sides of the first recess, and the opening slots support the two ends of the connecting shaft through bearings, thereby ensuring the rotation of the toothed roller relative to the precast pile.

[0017] Secondly, the present invention also provides a construction method for a composite pile structure that can reduce the influence of negative skin friction, comprising the following: A first toothed track is machined at the first recess on the outer surface of the precast pile, and a second toothed track is machined at the second recess on the inner surface of the first component; Several toothed components are set at each of the first toothed tracks, and the first component is fitted onto the circumferential direction of the precast pile; A steel reinforcement cage is placed in the foundation, and the cast-in-place pile section is then poured. The precast piles and the first component are hoisted, and the bottom end of the precast piles is connected to the top end of the cast-in-place piles to form a composite pile structure. Backfilling the side of the composite pile structure and the consolidation of the soil will cause the first component to sink, which will drive the toothed component to rotate, thereby driving the precast pile and the cast-in-place pile to generate an upward supporting force. After the strata have been left to stand for a set time and the backfill has been consolidated, the composite pile structure can be put into use.

[0018] The beneficial effects of the present invention are as follows: 1) The composite pile structure provided by this invention has a reasonable structural design. The cast-in-place pile is connected to the precast pile. The positive skin friction of the bearing soil layer of the cast-in-place pile can partially offset the negative skin friction of the upper half of the pile body. The precast pile is circumferentially equipped with a first component. The two are connected by a first toothed track and a second toothed track to support the toothed component, realizing a staggered power transmission form. The rotation effect of the toothed component is used to convert the negative skin friction of the pile side generated by soil consolidation into the upward support force of the precast pile and the cast-in-place pile, ensuring the reliability of the composite pile structure, improving the bearing capacity of the composite pile structure, and reducing the influence of negative skin friction on the composite pile structure.

[0019] 2) In this invention, a third recess is provided on the inner surface of the first component. After the soil is consolidated, a second grouting pipe can be inserted through the third recess. Grout is injected into the space between the precast pile and the first component through the second grouting pipe, so that the first component, the precast pile, and the cast-in-place pile become an integral structural component. This avoids the friction between the first component and the precast pile after the soil is consolidated, which is beneficial to ensuring the long-term performance of the composite pile structure.

[0020] 3) In this invention, the precast pile can be pre-embedded with a first grouting pipe, or a first grouting pipe can be set on its inner side. Grout can be injected into the bottom of the precast pile and the side of the pile bottom through the first grouting pipe, effectively filling the gap between the cast-in-place pile and the precast pile. This is used to fill the gap generated by the splicing of the precast pile and the cast-in-place pile after the composite pile structure is spliced, thereby improving the integrity of the composite pile structure.

[0021] 4) The first component in this invention includes multiple metal plates, which facilitates the transportation of the first component and makes it easy to assemble on site; a space is reserved between the bottom end of the first component and the top casing of the cast-in-place pile to provide space for the first component to settle relative to the precast pile.

[0022] 5) The composite pile structure provided by this invention has a reasonable construction procedure. First, the precast pile and the first component are assembled, then the cast-in-place pile is constructed, and then the precast pile and the cast-in-place pile are connected to form a composite pile structure. After backfilling the soil, the first component will sink during the soil consolidation process. However, under the action of the toothed component, the negative skin friction of the first component can be reversed and transmitted to the side of the precast pile, and an upward supporting force can be generated, thereby reducing the occurrence of composite pile sinking caused by soil consolidation. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0024] Figure 1 This is a schematic diagram of a composite pile structure that can reduce the influence of negative skin friction according to one or more embodiments of the present invention.

[0025] Figure 2 This is a schematic diagram of the first component of a composite pile structure capable of reducing the influence of negative skin friction according to one or more embodiments of the present invention.

[0026] Figure 3 This is a longitudinal cross-sectional view of a composite pile structure that can reduce the influence of negative skin friction according to one or more embodiments of the present invention.

[0027] Figure 4 This is a top view of a composite pile structure that can reduce the influence of negative skin friction according to one or more embodiments of the present invention.

[0028] Figure 5 This is a schematic diagram of a precast pile in a composite pile structure that can reduce the influence of negative skin friction according to one or more embodiments of the present invention.

[0029] Figure 6 This is a top view of a precast pile in a composite pile structure that can reduce the influence of negative skin friction according to one or more embodiments of the present invention.

[0030] Figure 7 This is a schematic diagram of the first component in a composite pile structure capable of reducing the influence of negative skin friction according to one or more embodiments of the present invention.

[0031] Figure 8 This is a schematic diagram of the grouting area of ​​the second grouting pipe in a composite pile structure that can reduce the influence of negative skin friction according to one or more embodiments of the present invention.

[0032] The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0033] Among them: 1. precast pile, 2. cast-in-place pile, 3. first toothed track, 4. first component, 5. toothed part, 6. second toothed track, 7. first grouting pipe, 8. third recess, 9. second grouting pipe, 10. open slot, 11. grouting area, 12. casing. Detailed Implementation

[0034] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0035] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. As described in the background section, existing composite pile structures suffer from the problem that negative skin friction cannot be reduced. In order to solve the above-mentioned technical problem, this invention proposes a composite pile structure that can reduce the influence of negative skin friction.

[0036] In a typical embodiment of the present invention, reference is made to Figure 1 , Figure 2 and Figure 4 As shown, a composite pile structure capable of reducing the influence of negative skin friction includes a cast-in-place pile 2, with a precast pile 1 connected to the top of the cast-in-place pile 2. A first annular component 4 is circumferentially fitted around the precast pile 2. At least one first recess is provided on the outer surface of the precast pile 1, and each first recess is provided with a first toothed track 3. The first toothed track 3 is arranged along the height direction of the precast pile 1. A second recess is provided on the inner surface of the first component 4, and a second toothed track 6 is provided in the second recess. The first toothed track 3 and the second toothed track 6 are arranged opposite to each other. Several toothed components 5 are fitted between the first toothed track and the second toothed track. The precast pile movably supports the toothed components 5. The toothed components 5 are rotatable relative to the precast pile 1. The negative skin friction of the first component is transmitted to the precast pile through the toothed components 5.

[0037] It should be noted that the cast-in-place pile 2 is constructed using existing cast-in-place pile construction techniques, and the total height of the cast-in-place pile and the precast pile is the same as that of a simple cast-in-place pile structure.

[0038] It is easy to understand that, reference Figure 3 As shown, a casing 12 is installed circumferentially at the top of the cast-in-place pile 2. The casing 12 is annular and has a set height. The height of the casing 12 is 1 / 10 to 1 / 7 of the height of the cast-in-place pile. The inner diameter of the annular casing is adapted to the diameter of the precast pile. The bottom of the precast pile 1 is inserted into the casing. The casing 12 has an opening so that the bottom end of the precast pile can be inserted into the casing and welded to the steel reinforcement at the top of the cast-in-place pile. In this embodiment, the bottom end of the first component 4 is spaced apart from the top end of the casing 12, thereby leaving space between the bottom end of the first component and the casing 12, providing space for the first component to settle relative to the precast pile.

[0039] It should be noted that the precast pile 1 can be a solid precast pile or a ring-shaped precast pile. When the precast pile is a solid precast pile, it is specifically a solid concrete pile; when the precast pile is a ring-shaped precast pile, it can be a steel pipe pile. Furthermore, considering that composite pile structures inevitably have issues such as gaps or protrusions between precast piles and cast-in-place piles, which may lead to pile cracking or excessive settlement due to stress concentration in the surrounding soil under the action of the pile, when precast pile 1 is a solid precast pile, multiple first grouting pipes are pre-embedded in the height direction of precast pile 1. The first grouting pipes 7 are pre-installed during the precast pile forming process to facilitate subsequent grouting; when the precast pile is a ring-shaped precast pile, refer to... Figure 5 and Figure 6 As shown, multiple first grouting pipes 7 are installed on the inner side of the precast pile 1. The first grouting pipes 7 can be placed in the hollow part of the annular precast pile. The first grouting pipes 7 can be evenly arranged in the circumferential direction of the precast pile.

[0040] Specifically, when the precast pile 1 is a solid precast pile, the first grouting pipe 7 is provided with multiple first outlets. Some of the first outlets are located at the bottom of the precast pile to fill the gap between the cast-in-place pile and the precast pile. Some of the first outlets are located on both sides of the bottom of the precast pile to grout and reinforce the soil around the pile at the connection between the cast-in-place pile and the precast pile. The first grouting pipe 7, through the setting of multiple first outlets, is used to fill the gap generated by the splicing of the precast pile and the cast-in-place pile after the composite pile structure is spliced, which plays a role in improving the integrity and preventing the generation of stress weak areas. When the precast pile is a steel pipe pile, the first grouting pipe 7 is also provided with multiple first outlets along the height direction of the precast pile. In addition to grouting the bottom of the precast pile, it can also grout the center of the steel pipe pile.

[0041] refer to Figure 7 As shown, considering that the toothed component 5 will fail after the composite pile structure is put into normal use, and the moving first component 4 will cause wear and collision with the precast pile 1, several third recesses 8 are provided on the inner surface of the first component. A second grouting pipe 9 is inserted into the third recess 8, and grout is injected into the space between the precast pile 1 and the first component 4 through the second grouting pipe 9. Along the height direction of the first component, the second grouting pipe 9 is provided with multiple second outlets, and the density of the second openings is greater than the density of the first openings. Through a high-pressure retraction grouting method, the second grouting pipe 9 sprays grout along the gap between the first component and the precast pile through the second outlets, and sprays out from the bottom end of the first component. (Refer to...) Figure 8 As shown, a grouting area 11 is formed around the first component 4 and the cast-in-place pile 2, which not only realizes the integration of the composite pile structure, but also ensures the reinforcement of the soil at the joint of the upper and lower pile sections, improves the integrity of the composite pile structure, and avoids the negative impact of subsequent devices on the composite pile structure.

[0042] In this embodiment, the first component 4 is specifically an outer sleeve. The inner diameter of the first component 4 is adapted to the outer diameter of the precast pile 1. Along the height direction of the first component, the first component 4 includes multiple metal plates. The multiple metal plates are assembled and welded into a ring-shaped first component 4, which facilitates the transportation of the first component and also facilitates on-site construction. The height of the first component 4 is lower than the height of the precast pile, which is conducive to the connection between the bottom end of the precast pile and the top end of the cast-in-place pile.

[0043] Understandably, the length of the first toothed track 3 is the same as the length of the first recess, and one end of the first toothed track 3 is located at the top of the precast pile; the length of the first recess is less than the height of the precast pile, which can effectively prevent the toothed component from coming off the first toothed track. Preferably, in order to ensure the uniformity of force at the precast pile, at least two first recesses are provided on the outer surface of the precast pile, and multiple first recesses are evenly provided on the side of the precast pile.

[0044] Correspondingly, the length of the second toothed track 6 is the same as the length of the second recess, and one end of the second toothed track 6 is located at the top of the first member; the length of the second recess is less than the height of the first member, and the depth of the second recess is less than the depth of the first recess.

[0045] In this embodiment, the toothed component 5 is a toothed roller with a gear-shaped longitudinal section. The first toothed track 3 and the second toothed track 6 are adapted to the shape of the toothed roller to mesh with it. The toothed roller is installed on the connecting shaft. The precast pile 1 has opening slots 10 on both sides of the first recess. The opening slots 10 support the two ends of the connecting shaft through bearings, thereby ensuring the rotation of the toothed roller relative to the precast pile. The connection between the connecting shaft and the bearing is filled with lubricating material so that when the second toothed track of the first component sinks, the toothed component is more likely to rotate.

[0046] In some examples, four or six first toothed tracks 3 can be set along the circumference of the precast pile 1, and four or six second toothed tracks 6 can also be set. Of course, the number of first toothed tracks 3 and second toothed tracks 6 can also be other numbers. Six to twenty toothed components can be set between the first toothed tracks and the second toothed tracks, and the spacing between adjacent toothed components at each first toothed track is set.

[0047] The composite pile structure provided in this embodiment connects cast-in-place piles and precast piles. The positive skin friction of the bearing soil layer of the cast-in-place pile can partially offset the negative skin friction of the upper half of the pile body. The precast pile is circumferentially equipped with a first component, and the two are connected by a first toothed track and a second toothed track to support the toothed component, realizing a staggered power transmission mode. The rotational effect of the toothed component is used to convert the negative skin friction of the pile side generated by soil consolidation into the upward supporting force of the precast pile and the cast-in-place pile, further reducing the negative skin friction and ensuring the reliability and long-term performance of the composite pile structure.

[0048] This embodiment also provides a construction method for composite pile structures that can reduce the influence of negative skin friction, including the following: A first toothed track is machined at the first recess on the outer surface of the precast pile, and a second toothed track is machined at the second recess on the inner surface of the first component; Several toothed components are set at each of the first toothed tracks, and the first component is fitted onto the circumferential direction of the precast pile; A steel reinforcement cage is placed in the foundation, and the cast-in-place pile section is then poured. The precast piles and the first component are hoisted, and the bottom end of the precast piles is connected to the top end of the cast-in-place piles to form a composite pile structure. Backfilling the side of the composite pile structure and the consolidation of the soil will cause the first component to sink, which will cause the toothed component to rotate, thereby driving the precast pile and the cast-in-place pile to generate an upward supporting force. After the strata have been left to stand for a set period of six months to a year, the backfill soil will be consolidated and the composite pile structure will be put into use.

[0049] It should be noted that when the precast pile is a steel pipe pile, grout is injected into the inner side of the steel pipe pile through the first grouting pipe. After the grouting is completed, a composite pile structure is formed.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite pile structure capable of reducing the influence of negative skin friction, characterized in that, The system includes a cast-in-place pile, with a precast pile connected to the top of the cast-in-place pile. A first annular component is circumferentially fitted around the precast pile. At least one first recess is provided on the outer surface of the precast pile, and each first recess is provided with a first toothed track. The first toothed track is positioned along the height direction of the precast pile. A second recess is provided on the inner surface of the first component, and a second toothed track is positioned within the second recess. The first and second toothed tracks are positioned opposite each other, and several toothed components are fitted and supported between them. The precast pile movably supports the toothed components, which are rotatable relative to the precast pile. The negative skin friction of the first component is transmitted to the precast pile through the toothed components. The toothed components are toothed rollers, which are mounted on a connecting shaft. Opening slots are provided on both sides of the first recess of the precast pile, and these opening slots support both ends of the connecting shaft via bearings. When the precast pile is a solid precast pile, several first grouting pipes are pre-embedded in the height direction of the precast pile. The first grouting pipe is provided with multiple first outlets, some of which are located at the bottom of the precast pile, and some of which are located on both sides of the bottom of the precast pile; When the precast pile is a ring-shaped precast pile, several first grouting pipes are installed on the inner side of the precast pile. The first grouting pipe is provided with multiple first outlets, some of which are located at the bottom of the precast pile, some of which are located on both sides of the bottom of the precast pile, and some of which are set along the height direction of the precast pile. The inner surface of the first component is provided with several third recesses, and a second grouting pipe is inserted into the third recesses to inject grout into the space between the precast pile and the first component through the second grouting pipe. Along the height direction of the first component, the second grouting pipe is provided with multiple second outlets.

2. The composite pile structure capable of reducing the influence of negative skin friction according to claim 1, characterized in that, The length of the first toothed track is the same as the length of the first recess, and one end of the first toothed track is located at the top of the precast pile; The length of the first recess is less than the height of the precast pile; The precast pile has multiple first recesses on its outer surface, and these first recesses are evenly distributed on the outer surface of the precast pile.

3. The composite pile structure capable of reducing the influence of negative skin friction according to claim 1, characterized in that, The length of the second toothed track is the same as the length of the second recess, and one end of the second toothed track is located at the top of the first component; The length of the second recess is less than the height of the first component.

4. The composite pile structure capable of reducing the influence of negative skin friction according to claim 1, characterized in that, The first component comprises multiple metal plates, which are assembled into a ring-shaped first component; The height of the first component is lower than the height of the precast pile.

5. A composite pile structure capable of reducing the influence of negative skin friction according to claim 1, characterized in that, A protective casing is provided circumferentially at the top of the cast-in-place pile, and the bottom end of the precast pile is inserted into the protective casing and welded to the reinforcing steel at the top of the cast-in-place pile. The distance between the bottom end of the first component and the top end of the casing is set.

6. A construction method for a composite pile structure capable of reducing the influence of negative skin friction according to any one of claims 1-5, characterized in that, Includes the following: A first toothed track is machined at the first recess on the outer surface of the precast pile, and a second toothed track is machined at the second recess on the inner surface of the first component; Several toothed components are set at each of the first toothed tracks, and the first component is fitted onto the circumferential direction of the precast pile; A steel reinforcement cage is placed in the foundation, and the cast-in-place pile section is then poured. The precast piles and the first component are hoisted, and the bottom end of the precast piles is connected to the top end of the cast-in-place piles to form a composite pile structure. Backfilling the side of the composite pile structure and the consolidation of the soil will cause the first component to sink, which will cause the toothed component to rotate, thereby driving the precast pile and the cast-in-place pile to generate an upward supporting force. After the strata have been left to stand for a set time and the backfill has been consolidated, the composite pile structure can be put into use.

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