Variable-diameter prefabricated pipe pile

Abstract

The present application relates to the technical field of building construction, and particularly relates to a variable-diameter prefabricated pipe pile, which comprises a connecting body, a concrete prefabricated pile and a variable-diameter pile body which are coaxially connected in sequence from top to bottom; the connecting body, the concrete prefabricated pile and the variable-diameter pile body are all hollow cylinders with cavities and are interconnected; the cavity of the connecting body is matched with the shape of the variable-diameter pile body to realize combined installation; the variable-diameter pile body comprises a variable-diameter part, a pile body and a pile tip part; the upper half of the cavity of the variable-diameter part is in the shape of a circular truncated cone and the diameter of the upper end is the same as that of the cavity of the concrete prefabricated pile, the middle part of the cavity is in the shape of a circular cylinder, and the lower half of the cavity is in the shape of an inverted circular truncated cone and is symmetrical to the shape of the upper half of the cavity; the cavity of the variable-diameter pile body penetrates to the lower bottom surface of the pile tip part, and the lower bottom surface of the pile tip part is provided with a pile tip. The present application can solve the problem that the depth of the pile body into the predetermined bearing stratum is limited, and the problem of poor anti-pulling performance, which may cause potential safety hazards for the foundation of a building.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, specifically to a variable diameter precast pipe pile. Background Technology

[0002] Silt is widely distributed along the Yellow River. When saturated silt is subjected to strong vibrations under earthquakes, dynamic loads, or other physical forces, it loses its shear strength when the effective stress approaches zero, resulting in a suspended state – a phenomenon known as liquefaction. Soil liquefaction can trigger geological disasters, threatening the ecological environment and the lives and property of people in the Yellow River basin. Adopting environmentally friendly liquefaction mitigation technologies can undoubtedly provide strong support for ecological civilization construction along the Yellow River. Traditionally, this type of soft soil foundation is treated by driving piles to increase the relative density of the soil between the piles, thus solving the liquefaction problem. However, traditional precast concrete piles are cylindrical with a uniform diameter, resulting in significant side friction during driving into the underground soil layers. This limits the depth to which the pile penetrates the intended bearing layer, failing to maximize the bearing capacity of the strata. Furthermore, because traditional precast concrete piles are hollow and generally manufactured using centrifugal processes, their inner walls are relatively smooth. Furthermore, after the pile is driven into the soft soil foundation, concrete needs to be injected into the hollow part, which results in low bonding strength between the driven core concrete and the inner wall of the hollow pile. The core concrete is easily pulled out, making the precast pile have poor pull-out resistance and creating hidden dangers for the foundation of the building. Summary of the Invention

[0003] The purpose of this invention is to provide a variable diameter precast pipe pile, which can solve the problem that the depth of the pile body into the predetermined bearing layer is relatively limited, and also solve the problem that the pull-out resistance of the precast pile center cavity is poor after casting, which poses a safety hazard to the foundation of the building.

[0004] To achieve the above objectives, a variable-diameter precast pipe pile is provided, comprising a connector, a precast concrete pile, and a variable-diameter pile body connected sequentially from top to bottom. The connector, precast concrete pile, and variable-diameter pile body are coaxially connected. Each of the connector, precast concrete pile, and variable-diameter pile body is a hollow column with an interconnected cavity. The cavity of the connector matches the shape of the variable-diameter pile body for assembly. The variable-diameter pile body comprises a variable-diameter section with an inverted frustum-shaped bottom, a cylindrical pile body, and an inverted frustum-shaped pile tip, connected sequentially from top to bottom. The upper half of the cavity of the variable-diameter section is frustum-shaped with the same diameter as the cavity of the precast concrete pile. The middle part of the cavity is cylindrical, and the lower half of the cavity is an inverted frustum-shaped section symmetrical to the frustum shape of the upper half of the cavity. The cavity of the variable-diameter pile body extends to the lower bottom surface of the pile tip, and a pile tip is provided on the lower bottom surface of the pile tip.

[0005] Furthermore, the connecting body, precast concrete pile, and variable diameter pile body are fixedly connected by welding. When two variable diameter precast pipe piles are connected, the cavity of the current variable diameter precast pipe connecting body is matched with the shape of the other variable diameter precast pipe variable diameter pile body to achieve combined installation, and fixedly connected by welding. The pile tip on the lower bottom surface of the pile tip is also fixedly connected by welding.

[0006] Furthermore, the cavity sidewalls of the connecting body, precast concrete pile, and variable diameter pile body are provided with anti-rotation vertical grooves.

[0007] Furthermore, the connecting body is provided with a pressure plate, and the lower part of the pressure plate is provided with a pressure-dividing block that fits into the cavity of the connecting body.

[0008] Furthermore, the outer surfaces of the connecting body, the precast concrete pile, and the variable diameter pile are marked with fixed intervals.

[0009] Furthermore, the pile tip is a cross-shaped pile tip.

[0010] Furthermore, the bottom part with an inverted frustum shape includes a cylindrical connecting part and an inverted frustum shape variable diameter body. The connecting part and the variable diameter body are provided with a number of downwardly inclined guide holes on their sides, and the guide holes connect the outside of the precast pile with the internal cavity.

[0011] Furthermore, the connection between the connecting body, the precast concrete pile, and the variable diameter pile body is integrally designed as an inverted frustum shape.

[0012] Principles and advantages:

[0013] 1. In this scheme, when the first variable-diameter precast pipe pile is driven, its variable-diameter pile body provides guidance during drilling, thereby reducing the side friction resistance of the pile body to a certain extent, so that the pile body can enter the predetermined bearing layer depth. Then, after the first variable-diameter precast pipe pile is driven, it is only necessary to insert the variable-diameter pile body of the second variable-diameter precast pipe pile into the connector of the first variable-diameter precast pipe pile. Since the cavity of the connector body matches the shape of the variable-diameter pile body to achieve assembly, the process of aligning the axes of the two variable-diameter precast pipe piles is eliminated during assembly, thus saving time and improving work efficiency. Finally, the diameter of the cavity structure inside the variable-diameter pile body increases from top to bottom and then decreases again, presenting a tank-like structure. This restricts the upward movement of the core concrete after it is injected and solidified, thereby increasing the bonding between the core concrete and the pile body, improving the tensile strength of the core concrete, and avoiding potential safety hazards to the foundation of the building.

[0014] 2. This scheme has a simple structure, is easy to operate, and penetrates deep into the bearing layer, effectively utilizing the bearing capacity of the bearing layer, making it suitable for widespread application.

[0015] 3. The design of the guide holes helps balance the pressure inside and outside the precast pile due to soil liquefaction, reducing insertion resistance and making pile driving smoother, thus improving efficiency. Furthermore, when pouring concrete into the central cavity of the precast pile, the concrete can flow through the guide holes to the outside of the pile. After solidification, it bonds the outer wall of the pile with the surrounding soil, improving the pile's pull-out resistance and mitigating soil liquefaction. Attached Figure Description

[0016] Figure 1 This is a structural schematic diagram of a variable-diameter precast pipe pile according to Embodiment 1 of the present invention;

[0017] Figure 2 for Figure 1 Schematic diagram of the structure after the assembly of medium-diameter precast pipe piles;

[0018] Figure 3 This is a schematic diagram of a variable diameter precast pipe pile according to Embodiment 2 of the present invention;

[0019] Figure 4 for Figure 3 A schematic diagram of the structure after the assembly of medium-diameter precast pipe piles. Detailed Implementation

[0020] The following detailed description illustrates the specific implementation method:

[0021] The reference numerals in the accompanying drawings include: 1. Connector; 2. Precast concrete pile; 3. Variable diameter pile body; 4. Variable diameter section; 5. Pile body; 6. Pile tip; 7. Drainage hole; 8.

[0022] Example 1

[0023] A type of variable diameter precast pipe pile, basically as follows Figure 1 , Figure 2 As shown, the structure includes a connecting body 1, a precast concrete pile 2, and a variable-diameter pile body 3, connected sequentially from top to bottom. The connecting body 1, precast concrete pile 2, and variable-diameter pile body 3 are coaxially connected. Each of these components is a hollow column with an interconnected cavity. The cavity of the connecting body 1 matches the shape of the variable-diameter pile body 3 for assembly. Markings at fixed intervals are provided on the outer surfaces of the connecting body 1, precast concrete pile 2, and variable-diameter pile body 3. In this embodiment, white paint is used to mark the pile body at 1-meter intervals.

[0024] The variable-diameter pile body 3 includes, from top to bottom, a variable-diameter section 4 (including a truncated cone-shaped bottom), a cylindrical pile body 5, and a truncated cone-shaped pile tip 6, connected sequentially. The connecting body 1, the precast concrete pile 2, and the cavity sidewalls of the variable-diameter pile body 3 are provided with anti-rotation vertical grooves. In this embodiment, anti-rotation vertical grooves are only provided on the cavity sidewalls of the variable-diameter pile body 3 to prevent rotation of the filling concrete, thus ensuring the overall stability of the variable-diameter precast pipe pile.

[0025] The upper half of the cavity of the variable diameter section 4 is shaped like a frustum and its upper diameter is the same as the diameter of the cavity of the precast concrete pile 2. The middle part of the cavity is cylindrical and the lower half of the cavity is shaped like an inverted frustum, which is symmetrical to the frustum shape of the upper part of the cavity.

[0026] The diameter of the cylindrical pile body 5 and the truncated cone-shaped pile tip 6 is the same as the diameter of the precast concrete pile 2. The cavity of the variable-diameter pile body 3 extends to the lower bottom surface of the pile tip 6. A pile tip 7 is provided on the lower bottom surface of the pile tip 6. The pile tip 7 is only provided on the first driven precast pile, and it is not necessary to provide a pile tip 7 on subsequent precast piles. The pile tip 7 is a cross-shaped pile tip 7. In other embodiments, the pile tip 7 can be set as a cone.

[0027] The connecting body 1, the precast concrete pile 2, and the variable diameter pile body 3 are fixedly connected by welding. When two variable diameter precast pipe piles are connected, the cavity of the current variable diameter precast pipe connecting body 1 is matched with the shape of the other variable diameter precast pipe variable diameter pile body 3 to achieve combined installation, and is fixedly connected by welding. The pile tip 7 on the bottom surface of the pile tip 6 is also fixedly connected by welding.

[0028] The connecting body 1 is provided with a pressure plate, and the lower part of the pressure plate is provided with a pressure-distributing block that fits into the cavity of the connecting body 1. This achieves the purpose of buffering and evenly distributing the impact force, avoiding the concentration of impact force, thereby preventing the hydraulic hammer pile driver from directly hammering the end of the connecting body 1, and thus avoiding damage to the upper end of the connecting body 1.

[0029] The bottom-shaped variable diameter section 4 includes a cylindrical connecting part and an inverted frustum-shaped variable diameter body. The connecting part and the variable diameter body are provided with a plurality of inclined downward-facing guide holes 8 on their sides. The guide holes 8 connect the outside of the precast pile with the internal cavity.

[0030] In this design, when the first variable-diameter precast pipe pile is driven, the variable-diameter section 4 of the pile body 3 provides guidance during drilling, thereby reducing the side friction resistance of the pile body and facilitating its entry into the predetermined bearing stratum depth. After the first variable-diameter precast pipe pile is driven, only the variable-diameter section 3 of the second variable-diameter precast pipe pile needs to be inserted into the connector 1 of the first pile. Since the cavity of the connector 1 matches the shape of the variable-diameter section 3 for assembly, the process of aligning the axes of the two piles is eliminated, saving time and improving efficiency. Finally, the cavity structure inside the variable-diameter section 3 has a diameter that gradually decreases from top to bottom, resembling a can-like structure. This restricts the upward movement of the core concrete after it has solidified, increasing the bond between the core concrete and the pile body, improving the tensile strength of the core concrete, and preventing potential safety hazards to the building foundation.

[0031] Due to soil liquefaction, the guide holes can balance the pressure inside and outside the precast pile, reducing insertion resistance and making pile driving smoother, thus improving pile driving efficiency. Furthermore, when pouring concrete into the central cavity of the precast pile, the concrete can flow through the guide holes to the outside of the precast pile. After solidification, it can bond the outer wall of the precast pile with the surrounding soil, improving the pull-out resistance of the precast pile and addressing soil liquefaction. Simultaneously, the guide holes allow concrete to flow into the gap between the variable-diameter pile body 3 and the connecting body 1, achieving better pile splicing.

[0032] This solution has a simple structure, is easy to operate, and penetrates deep into the bearing layer, effectively utilizing the bearing capacity of the bearing layer, making it suitable for widespread application.

[0033] Example 2

[0034] The difference between Example 2 and Example 1 is as follows: Figure 3 , Figure 4 As shown, the connection between the connecting body 1, the precast concrete pile 2, and the variable diameter pile body 3 and variable diameter section 4 is integrally designed as an inverted frustum. This integral inverted frustum design allows for greater compression of the soil when the precast pile is inserted, thus mitigating soil liquefaction to some extent. Combined with the inclusion of a guide hole, after solidification, the outer wall of the precast pile can be bonded to the surrounding soil, improving the pile's pull-out resistance and further addressing soil liquefaction.

[0035] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, based on the guidance provided in this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A type of precast pipe pile with variable diameter, characterized in that: The system comprises a connecting body, a precast concrete pile, and a variable-diameter pile body, which are connected sequentially from top to bottom. These components are coaxially connected and are all hollow cylinders with interconnected cavities. The cavity of the connecting body matches the shape of the variable-diameter pile body for assembly. The variable-diameter pile body comprises a variable-diameter section with an inverted frustum-shaped bottom, a cylindrical pile body, and an inverted frustum-shaped pile tip, all connected sequentially from top to bottom. The upper half of the cavity of the variable-diameter section is frustum-shaped with the same diameter as the cavity of the precast concrete pile. The middle part of the cavity is cylindrical, and the lower half is an inverted frustum-shaped section symmetrical to the upper half. The cavity of the variable-diameter pile body extends to the lower surface of the pile tip, where a pile tip is located.

2. A variable-diameter precast pipe pile according to claim 1, characterized in that: The connecting body, precast concrete pile, and variable diameter pile body are fixedly connected by welding. When two variable diameter precast pipe piles are connected, the cavity of the current variable diameter precast pipe pile connecting body is matched with the shape of the variable diameter pile body of the other variable diameter precast pipe pile to achieve combined installation, and fixedly connected by welding. The pile tip on the bottom surface of the pile tip is also fixedly connected by welding.

3. A variable-diameter precast pipe pile according to claim 2, characterized in that: The cavity sidewalls of the connector, precast concrete pile, and variable diameter pile are provided with anti-rotation vertical grooves.

4. A variable-diameter precast pipe pile according to claim 3, characterized in that: The connector is provided with a pressure plate, and the lower part of the pressure plate is provided with a pressure-dividing block that fits into the cavity of the connector.

5. A variable-diameter precast pipe pile according to claim 1, characterized in that: The outer surfaces of the connector, precast concrete pile, and variable diameter pile are marked with fixed intervals.

6. A variable-diameter precast pipe pile according to claim 1, characterized in that: The pile tip is cross-shaped.

7. A variable-diameter precast pipe pile according to claim 1, characterized in that: The bottom is a truncated cone-shaped variable diameter section, which includes a cylindrical connecting part and a truncated cone-shaped variable diameter body. The connecting part and the variable diameter body are provided with a number of inclined downward guide holes on their sides. The guide holes connect the outside of the variable diameter precast pipe pile with the internal cavity.

8. A variable-diameter precast pipe pile according to claim 7, characterized in that: The connection between the connector, the precast concrete pile, and the variable diameter pile body is integrally designed as an inverted frustum shape.

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