Bridge deep pile foundation construction method

Abstract

The application discloses a bridge deep pile foundation construction method, and relates to the technical field of bridge engineering, which comprises the following steps of outer protection cylinder installation, construction environment cleaning, pile hole excavation, hole cleaning, inner protection cylinder installation, outer ring steel mesh installation, concrete protection wall pouring, inner protection cylinder pulling out, ring inner steel reinforcement cage installation, ring inner concrete pouring, concrete curing and outer protection cylinder pulling out. The application optimizes the construction process, effectively guarantees the hole forming quality, optimizes the concrete pouring process, effectively prevents quality defects such as broken piles, mud inclusion and segregation, guarantees the construction quality of the pile foundation, improves the overall performance of the pile body, solves the problems that the traditional deep pile foundation construction is prone to hole collapse under complex geological conditions and the concrete pouring quality is difficult to control, and meets the increasing demand of current bridge construction for high-reliability deep foundation.

Description

Technical Field

[0001] This application relates to the technical field of bridge engineering, and in particular to a method for constructing deep pile foundations for bridges. Background Technology

[0002] In bridge engineering, deep pile foundations are a crucial component of the supporting structure, and their construction quality directly determines the overall stability, load-bearing capacity, and long-term durability of the bridge. With the rapid development of modern transportation construction, bridge engineering is increasingly moving towards larger spans and higher loads, which places more stringent demands on the load-bearing performance and service life of deep pile foundations.

[0003] However, traditional techniques often face a series of technical challenges when constructing deep pile foundations under complex geological conditions, such as soft soil, sand layers, or gravel layers. For example, during the drilling stage, problems such as borehole wall collapse, diameter reduction, or sand inrush are prone to occur; during the concrete pouring process, quality problems such as pile breakage, mud inclusion, and segregation can easily occur due to improper operation or geological conditions, making it difficult to effectively control the uniformity and density of the pile concrete, thus affecting the final pile quality.

[0004] Therefore, there is an urgent need to develop a new method for deep pile foundation construction that can effectively ensure the quality of hole formation, optimize the concrete pouring process, and improve the overall performance of the pile body, so as to meet the growing demand for high-reliability deep foundations in current bridge construction. Summary of the Invention

[0005] To address the problems existing in the prior art, this application provides a method for constructing deep pile foundations for bridges.

[0006] This application provides a method for constructing deep pile foundations for bridges, which adopts the following technical solution: A method for constructing deep pile foundations for bridges includes the following steps: Step 1, Installation of outer casing: Determine the construction location of the pile foundation and drive the outer casing into the soil layer at the bottom of the construction location; Step 2, Cleaning up the construction environment: Remove accumulated water and silt from inside the outer casing; Step 3, Pile Hole Excavation: Drill pile holes in the soil layer inside the outer casing using a drilling machine, and ensure that the drilling depth meets the design requirements; Step 4: Clean the hole: Remove the accumulated water and sediment from the pile hole; Step 5: Inner casing installation: Install the inner casing inside the pile hole. The bottom of the inner casing is pressed against the stabilizing layer at the bottom of the pile hole. The top of the inner casing is higher than the ground, and the diameter of the inner casing is smaller than the diameter of the pile hole. Step 6: Install the outer ring steel mesh: Install the outer ring steel mesh in the annular space between the inner casing and the pile hole; Step 7: Concrete wall pouring: Pour concrete into the annular space between the inner casing and the pile hole to form a concrete wall. Step 8: Removal of the inner casing: After the concrete wall reaches its initial setting strength, remove the inner casing. Step 9: Installation of the inner steel reinforcement cage: Hoist the tied steel reinforcement cage into the concrete retaining wall and adjust the position of the steel reinforcement cage. Step 10: Concrete pouring within the enclosure. Concrete is poured into the concrete retaining wall, and during the pouring process, the concrete is vibrated and compacted. Step 11, Concrete Curing: Curing the poured concrete; Step 12, Removal of the outer casing: After the concrete reaches the design strength, remove the outer casing.

[0007] Optionally, the diameter of the outer casing is 100-200 cm larger than the designed pile diameter, and the outer casing is driven into the soil to a depth of not less than 2 m during installation, and the top of the outer casing is not less than 50 cm above the ground.

[0008] Optionally, the inner casing includes multiple interconnected pipe sections, and a connecting structure is provided between adjacent pipe sections.

[0009] Optionally, the connection structure includes a connecting sleeve fixedly disposed at the bottom of the tube and a limiting block fixedly disposed on the side wall of the connecting sleeve. The connecting sleeve is adapted to the inner diameter of the tube and is used to insert into the top of an adjacent tube. The top of the tube has an insertion groove communicating with the inner wall of the tube and used for limiting insertion. The side wall of the insertion groove has a limiting slot for the limiting block to be screwed in.

[0010] Optionally, the outer wall diameter of the tube is 20-40cm smaller than the designed pile hole diameter, and the bottom of the inner casing is provided with a base plate.

[0011] Optionally, during installation, it is necessary to ensure the concentricity between the inner casing and the pile hole, and the inner casing should be fixed to the pile hole wall using positioning clamps.

[0012] Optionally, after the inner casing is installed inside the pile hole, a quick-release template is set in the annular space between the inner casing and the pile hole. The quick-release template includes several arc-shaped plates spliced ​​in sequence. The arc-shaped plates are adapted to the outer wall of the inner casing and are attached to the outer wall of the inner casing. Each arc-shaped plate is fixed to the outer wall of the inner casing by a clamp.

[0013] Optionally, after the inner casing is removed, the integrity of the concrete retaining wall is tested.

[0014] Optionally, when pouring concrete into the concrete retaining wall, the concrete can be poured in layers, with each layer having a height of 300-500mm.

[0015] In summary, this application includes at least one of the following beneficial technical effects: 1. This application effectively ensures the quality of borehole formation and optimizes the concrete pouring process through optimized construction technology, thereby improving the overall performance of the pile body. Specifically, in the initial stage of construction, the pile foundation location can be determined by driving an outer casing into the construction site, effectively isolating surface soil and surface water from interfering with the borehole formation operation, and clearing accumulated water and silt inside the outer casing to provide a good environment for subsequent construction; after the pile hole is formed, clearing accumulated water and sediment inside the pile hole can avoid affecting the quality of pile formation; then, an inner casing is installed inside the pile hole and its bottom is compacted to form a stabilizing layer, and an outer ring of steel mesh is installed in the annular space between the inner casing and the pile hole, and concrete is poured to form a concrete retaining wall. After the concrete retaining wall is formed, it plays the role of supporting the hole wall, completely eliminating the risk of hole wall collapse and soil mixing during subsequent construction. Subsequently, the inner casing was removed, and under the protection of the solidified concrete wall, the reinforcing cage was installed, and the concrete within the ring was poured and vibrated. This fundamentally ensured the density and uniformity of the concrete, effectively preventing quality defects such as broken piles, mud inclusions, and segregation. This effectively guaranteed the construction quality of the pile foundation and solved the problems of easy borehole collapse and difficulty in controlling concrete pouring quality in traditional deep pile foundation construction under complex geological conditions. It meets the growing demand for highly reliable deep foundations in current bridge construction.

[0016] 2. The inner casing is composed of multiple sections of pipe spliced ​​together, and adjacent pipes are connected by a connecting structure, which facilitates transportation and installation; and pipes of corresponding lengths can be set according to actual construction needs to improve adaptability and practicality.

[0017] 3. This application utilizes a quick-release formwork in the annular space between the inner casing and the pile hole to effectively prevent concrete from adhering to the side wall of the inner casing during the concrete wall pouring process, facilitating the subsequent removal of the inner casing. Furthermore, the quick-release formwork consists of several sequentially spliced ​​arc-shaped plates adapted to the outer wall of the inner casing. After the inner casing is removed, the quick-release formwork can be easily disassembled from the concrete wall, further improving construction convenience. Attached Figure Description

[0018] Figure 1 This is a process flow diagram of an embodiment of this application; Figure 2 This is a diagram illustrating the construction steps for installing the inner casing in an embodiment of this application; Figure 3 This is a schematic diagram illustrating the structure of the tube according to an embodiment of this application; Figure 4 This is a schematic diagram illustrating the structure of the quick-release template in an embodiment of this application; Figure 5 This is a diagram illustrating the construction steps of concrete pouring within the circle, as described in the embodiments of this application.

[0019] Explanation of reference numerals in the attached drawings: 1. Outer casing; 2. Inner casing; 21. Pipe; 211. Insertion groove; 212. Limiting slot; 22. Connecting sleeve; 23. Limiting block; 3. Quick-release formwork; 31. Curved plate; 32. Hoop; 4. Outer ring steel mesh; 5. Concrete retaining wall; 6. Inner ring steel cage; 7. Inner ring concrete. Detailed Implementation

[0020] The following will be combined with the appendix Figure 1 -Appendix Figure 5 The technical solutions in the embodiments of the present invention are clearly and completely described herein. The described embodiments are only possible technical implementations of the present invention and not all possible implementations. Those skilled in the art can obtain other embodiments in conjunction with the embodiments of the present invention without creative effort, and these embodiments are also within the protection scope of the present invention.

[0021] The inventors of this application have discovered that traditional bridge deep pile foundation construction techniques often face a series of technical challenges when carried out in areas with complex geological conditions such as soft soil, sand layers, or gravel layers. For example, during the hole-forming stage, problems such as hole wall collapse, diameter reduction, or sand inrush are prone to occur; during the concrete pouring process, quality hazards such as pile breakage, mud inclusion, and segregation can easily occur due to improper operation or geological conditions, making it difficult to effectively control the uniformity and density of the pile concrete, thus affecting the final pile quality. Therefore, this application discloses a bridge deep pile foundation construction method, mainly adopting the following scheme: This application discloses a method for constructing deep pile foundations for bridges. (Refer to...) Figure 1 The process includes steps such as installing the outer casing 1, cleaning the construction environment, excavating the pile hole, cleaning the hole, installing the inner casing 2, installing the outer ring steel mesh 4, pouring the concrete wall 5, removing the inner casing 2, installing the inner steel cage 6, pouring the inner concrete 7, curing the concrete, and removing the outer casing 1. By executing these steps in an orderly manner, the quality of the hole can be effectively guaranteed, the concrete pouring process can be optimized, and the overall performance of the pile can be improved.

[0022] Reference Figure 2Specifically, the installation of the outer casing 1 involves piling equipment and the outer casing 1 itself. The outer casing 1 is generally made of steel, possessing good strength and corrosion resistance, capable of withstanding external forces during construction and resisting environmental erosion. In certain special cases, high-strength plastic materials can also be used to make the outer casing 1; this material is lightweight, low-cost, and has a certain degree of corrosion resistance. The piling equipment can be a diesel hammer pile driver, characterized by high piling efficiency and suitable for harder soil layers; or a hydraulic pile driver, which has low noise and vibration, suitable for use in areas with high environmental requirements. The diameter of the outer casing 1 is 100-200cm larger than the designed pile diameter, providing sufficient operating space for subsequent construction. During installation, the outer casing 1 is driven into the soil layer at the bottom of the construction site to a depth of not less than 2m to ensure its stability. The top of the outer casing 1 is at least 50cm above the ground to prevent surface water from flowing into it. The piling equipment uses its own impact force or pressure to gradually press the outer casing 1 into the soil layer. During this process, the vertical angle of the outer casing 1 needs to be continuously adjusted to ensure the accuracy of its installation position.

[0023] The cleanup process primarily involves removing accumulated water from inside the outer casing 1, requiring pumping equipment and a mud pump. Pumping equipment, such as submersible pumps, can reach the bottom of the outer casing 1 to extract water; these pumps are characterized by high flow rate and high head. Self-priming pumps can also be used, offering advantages such as easy installation and simple operation. Mud pumps transport sludge through pipelines to designated locations for subsequent processing. Submersible pumps use a motor to drive an impeller, generating suction to draw water into the pump body and discharge it; mud pumps rely on the movement of a piston or screw to transport the sludge.

[0024] In the pile hole excavation process, a drilling rig is used to drill the pile hole inside the soil layer on the inner side of the outer casing 1. Common drilling rigs include rotary drilling rigs and impact drilling rigs. Rotary drilling rigs are suitable for various soil layers and have the advantages of fast drilling speed and high precision; impact drilling rigs are suitable for use in harder strata such as gravel layers. In some special strata, long auger drilling rigs can also be selected, which are suitable for various complex geological conditions. During the drilling process, the drilling depth must be controlled according to the design requirements to ensure that the design standards are met, and the angle of the pile hole must be kept vertical. The drilling rig breaks up the soil layer through the rotation or impact of the drill bit, while simultaneously discharging the drilled soil and debris out of the hole.

[0025] The borehole cleaning step is to remove accumulated water and sediment from the pile hole, ensuring its cleanliness. This requires equipment such as a slurry suction cylinder, which can directly extract the water and sediment from the pile hole. In some cases, an air suction machine can also be used for cleaning, which uses compressed air to suck out the mud and sediment from the hole. The slurry suction cylinder is lowered into the pile hole via ropes or chains, then collects the sediment and water, and lifts it to the ground for further cleaning.

[0026] Reference Figure 2 In the installation step of the inner casing 2, the inner casing 2 is hoisted into the pile hole, and the bottom of the inner casing 2 is pressed tightly against the stabilizing layer at the bottom of the pile hole, and the top of the inner casing 2 is ensured to be higher than the ground. The diameter of the inner casing 2 must be smaller than the diameter of the pile hole, so that an annular space can be formed between the inner casing 2 and the hole wall, which facilitates the subsequent construction of the concrete retaining wall 5.

[0027] Reference Figure 2 and Figure 3 Specifically, the inner casing 2 comprises multiple interconnected pipe sections 21, typically made of steel, possessing sufficient strength and rigidity. In applications with stringent weight requirements, aluminum alloy pipe sections 21 may also be used. Adjacent pipe sections 21 are connected via a connecting structure, and the bottom of the lowest pipe section 21 of the inner casing 2 is fixedly fitted with a closed base plate to prevent concrete from entering the inner casing 2 during the pouring of the concrete retaining wall 5. The outer diameter of the outer wall of the pipe section 21 is 20-40 cm smaller than the designed diameter of the pile hole. During installation, the concentricity between the inner casing 2 and the pile hole must be ensured, which can be measured and adjusted using measuring instruments. These instruments can be total stations or levels, capable of accurately measuring the position and verticality of the inner casing 2. Simultaneously, the inner casing 2 is fixed to the pile hole wall using positioning clamps, which can be wooden or metal, to prevent displacement of the inner casing 2 during construction.

[0028] Reference Figure 3Specifically, the connection structure includes a connecting sleeve 22 fixedly installed at the bottom of the tube 21 and a limiting clip fixedly installed on the side wall of the connecting sleeve 22. The connecting sleeve 22 is adapted to the inner diameter of the tube 21 and is used to insert into the top of the adjacent tube 21. The top of the tube 21 has an insertion groove 211 that communicates with the inner wall of the tube 21 and is used for the insertion of the limiting clip 23. The side wall of the insertion groove 211 has a limiting clip groove 212 for the limiting clip 23 to be screwed in. During installation, the tubes 21 can be spliced ​​together on the construction site according to the required length of the inner tube 2 to form the inner tube 2, and then the spliced ​​inner tubes 2 can be hoisted into the pile hole. Alternatively, one tube 21 can be hoisted into the opening of the pile hole first, and then another tube 21 can be connected to the previous tube 21. Then, the connected tubes 21 can be hoisted into the pile hole for a certain distance, and then the subsequent tubes 21 can be connected in sequence.

[0029] Reference Figure 2 and Figure 4 Furthermore, after the inner casing 2 is installed, a quick-release template 3 is installed in the annular space between the inner casing 2 and the pile hole. The quick-release template 3 includes several arc-shaped plates 31 and clamps 32 spliced ​​together in sequence. The arc-shaped plates 31 are adapted to the outer wall of the inner casing 2 and are attached to the outer wall of the inner casing 2. Each arc-shaped plate 31 is fixed to the outer wall of the inner casing 2 by clamps 32. The arc-shaped plates 31 can be made of wood, which is low in cost and easy to process; or they can be made of plastic, which is lightweight and has a certain degree of flexibility. The clamps 32 can be steel strap clamps 32 or rubber clamps 32. Steel strap clamps 32 have high strength, while rubber clamps 32 have good sealing performance. This quick-release template 3 can effectively prevent concrete from sticking to the side wall of the inner casing 2 during the pouring of the concrete retaining wall 5, making it convenient to remove the inner casing 2 later. Furthermore, after the inner casing 2 is removed, it is easy to disassemble the quick-release formwork 3 from the concrete retaining wall 5, further improving the convenience of construction.

[0030] Reference Figure 2 In the installation of the outer ring steel mesh 4, it is generally made of steel bars tied together. The size of the outer ring steel mesh 4, as well as the specifications and spacing of the steel bars, must be determined according to the design requirements to ensure that it can be installed in the annular space between the inner casing 2 and the pile hole. At the same time, after the outer ring steel mesh 4 is installed, the concentricity between the outer ring steel mesh 4 and the inner casing 2 must be ensured to improve the overall uniformity of the concrete retaining wall 5 after molding. This ensures that the load-bearing capacity of the molded concrete retaining wall 5 is basically consistent at various locations, thereby enhancing the structural strength of the concrete retaining wall 5 and effectively supporting the hole wall. This completely eliminates the risk of hole wall collapse and soil mixing during subsequent construction, providing a reliable foundation guarantee for the later pouring and molding of the pile foundation.

[0031] Reference Figure 2 and Figure 5 In the concrete retaining wall 5 pouring step, the concrete mix proportions and slump should be checked before pouring to ensure the quality of the concrete. A concrete pump can be used to transport the concrete into the annular space to form the concrete retaining wall 5. During the pouring process, attention should be paid to controlling the pouring speed and height to ensure the compactness of the concrete.

[0032] The removal of the inner casing 2 is performed after the concrete retaining wall 5 has reached its initial setting strength. The inner casing 2 is then pulled out using lifting equipment. This lifting equipment can be a crane or a winch. Cranes have the advantages of large lifting capacity and a wide working range; winches are simple in structure and easy to operate. After the concrete retaining wall 5 has reached its initial setting strength, the inner casing 2 is pulled out using the lifting equipment. During the removal process, the pulling force should be applied slowly and evenly to avoid damaging the inner casing 2 and the concrete retaining wall 5.

[0033] After the inner casing 2 is removed, the integrity of the concrete retaining wall 5 is inspected. The inspection equipment can be an ultrasonic detector or a radar detector. An ultrasonic detector uses ultrasonic waves to detect defects and damage inside the concrete; a radar detector uses electromagnetic waves to detect the structure and quality of the concrete. Through inspection, problems such as cracks and holes in the concrete retaining wall 5 can be detected in a timely manner, allowing for appropriate repair measures to be taken and ensuring the safety and quality of subsequent construction.

[0034] Reference Figure 5 In the installation step of the inner steel reinforcement cage 6, the steel reinforcement cage is made of steel bars tied or welded together. During hoisting, a crane should be used to slowly lift the steel reinforcement cage into the concrete retaining wall 5, and the position of the steel reinforcement cage should be adjusted so that it is in the center of the concrete retaining wall 5.

[0035] Reference Figure 5 In the concrete pouring process within the circle, a layered pouring method is adopted, with each layer having a height of 300-500mm. During the pouring process, a vibratory compactor is used to compact the concrete; the vibratory compactor can be an immersion vibrator, which makes the concrete more compact.

[0036] The curing process for concrete requires selecting appropriate curing methods based on the type of concrete and environmental conditions. Common curing methods include covering and watering curing, and plastic film curing. Covering and watering curing involves covering the concrete surface with materials such as straw mats and watering regularly to keep the concrete surface moist; plastic film curing involves covering the concrete surface with a plastic film to prevent moisture evaporation.

[0037] The outer casing 1 is removed after the concrete reaches the design strength. The outer casing 1 is then removed using the reverse function of the pile driving equipment or a special pile extraction device.

[0038] The implementation principle of a bridge deep pile foundation construction method according to an embodiment of this application is as follows: This application effectively ensures the quality of hole formation and optimizes the concrete pouring process through the optimization of construction technology, thereby improving the overall performance of the pile body. In the early stage of construction, the pile foundation position can be located by driving an outer casing 1 into the construction location, and the interference of surface soil and surface water on the hole formation operation can be effectively isolated. The water and silt inside the outer casing 1 are cleaned to provide a good environment for subsequent construction. After the pile hole is formed, the water and sediment inside the pile hole can be cleaned to avoid affecting the quality of pile formation. Then, an inner casing 2 is installed in the pile hole and its bottom is pressed to stabilize the layer. An outer ring steel mesh 4 is installed in the annular space between the inner casing 2 and the pile hole, and concrete is poured to form a concrete retaining wall 5. After the concrete retaining wall 5 is formed, it plays the role of supporting the hole wall, completely eliminating the risk of hole wall collapse and soil mixing in the subsequent construction process. Subsequently, the inner casing 2 is removed, and under the protection of the solidified concrete retaining wall 5, the reinforcing cage is installed, and the concrete 7 within the ring is poured and vibrated. This fundamentally ensures the density and uniformity of the concrete, effectively preventing quality defects such as broken piles, mud inclusions, and segregation, thus effectively guaranteeing the construction quality of the pile foundation. Compared with traditional construction methods, this method can better guarantee the quality of hole formation, optimize the concrete pouring process, and improve the overall performance of the pile body under complex geological conditions, meeting the current demand for high-reliability deep foundations in bridge construction. It has significant practicality and innovation.

[0039] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for constructing deep pile foundations for bridges, characterized in that, Includes the following steps: Step 1, Installation of outer casing (1): Determine the construction location of the pile foundation and drive the outer casing (1) into the soil layer at the bottom of the construction location; Step 2, Cleaning up the construction environment: Remove the accumulated water and silt inside the outer casing (1); Step 3, pile hole excavation: Drill pile holes in the soil layer inside the outer casing (1) using a drilling machine, and ensure that the drilling depth meets the design requirements; Step 4: Clean the hole: Remove the accumulated water and sediment from the pile hole; Step 5, Inner casing (2) installation: Install inner casing (2) in the pile hole. The bottom of inner casing (2) is pressed against the stabilizing layer at the bottom of the pile hole. The top of inner casing (2) is higher than the ground and the diameter of inner casing (2) is smaller than the diameter of the pile hole. Step 6, installation of outer ring steel mesh (4): Install the outer ring steel mesh (4) in the annular space between the inner casing (2) and the pile hole; Step 7, Concrete wall (5) pouring: Pour concrete into the annular space between the inner casing (2) and the pile hole to form concrete wall (5); Step 8, Removal of inner casing (2): After the concrete wall (5) reaches its initial setting strength, remove the inner casing (2); Step 9, Installation of the inner steel cage (6): Hoist the tied steel cage into the concrete retaining wall (5) and adjust the position of the steel cage; Step 10: Concrete pouring (7) inside the ring. Concrete is poured into the concrete retaining wall (5), and the concrete is vibrated during the pouring process. Step 11, Concrete Curing: Curing the poured concrete; Step 12, Removal of outer casing (1): After the concrete reaches the design strength, remove the outer casing (1).

2. The method for constructing deep pile foundations for bridges according to claim 1, characterized in that: The outer casing (1) has a diameter 100-200 cm larger than the designed pile diameter, and the outer casing (1) is driven into the soil to a depth of not less than 2 m during installation. The top of the outer casing (1) is not less than 50 cm above the ground.

3. The method for constructing deep pile foundations for bridges according to claim 1, characterized in that: The inner sleeve (2) includes multiple sections of pipe (21) spliced ​​together, and a connecting structure is provided between adjacent pipes (21).

4. The method for constructing deep pile foundations for bridges according to claim 3, characterized in that: The connection structure includes a connecting sleeve (22) fixedly disposed at the bottom of the tube (21) and a limiting block (23) fixedly disposed on the side wall of the connecting sleeve (22). The connecting sleeve (22) is adapted to the inner diameter of the tube (21) and is used to insert into the top of the adjacent tube (21). The top of the tube (21) is provided with a plug groove (211) that communicates with the inner wall of the tube (21) and is used for limiting insertion. The side wall of the plug groove (211) is provided with a limiting groove (212) for the limiting block (23) to be screwed in.

5. A method for constructing deep pile foundations for bridges according to claim 3, characterized in that: The outer wall diameter of the tube (21) is 20-40cm smaller than the diameter of the designed pile hole, and the inner protective tube (2) is located at the bottom of the tube (21) at the bottom, which is fixedly equipped with a closed bottom plate.

6. The method for constructing deep pile foundations for bridges according to claim 1, characterized in that: When installing the inner casing (2), it is necessary to ensure the concentricity between the inner casing (2) and the pile hole, and the inner casing (2) and the pile hole wall are fixed with positioning clamps.

7. The method for constructing deep pile foundations for bridges according to claim 1, characterized in that: After the inner casing (2) is installed inside the pile hole, a quick-release template (3) is set in the annular space between the inner casing (2) and the pile hole. The quick-release template (3) includes several arc-shaped plates (31) spliced ​​in sequence. The arc-shaped plates (31) are adapted to the outer wall of the inner casing (2) and are attached to the outer wall of the inner casing (2). Each arc-shaped plate (31) is fixed to the outer wall of the inner casing (2) by a clamp (32).

8. The method for constructing deep pile foundations for bridges according to claim 1, characterized in that: After the inner casing (2) is removed, the integrity of the concrete retaining wall (5) is tested.

9. A method for constructing deep pile foundations for bridges according to claim 1, characterized in that: When pouring concrete into the concrete retaining wall (5), the concrete is poured in layers, and the height of each layer is 300-500mm.

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