Steel pipe pile construction process

Steel pipe pile definition

Steel pipe pile is a hollow steel pipe, usually made of straight seam submerged arc welded steel pipe (LSAW steel pipe), spiral welded steel pipe (SSAW) or seamless steel pipe. Its high strength and durability make it an ideal choice for foundation construction.

1. Overview of steel pipe pile design

The support design uses Q345 seamless steel pipe of Φ194×12.0, with 3 Φ25 grade 3 steel in the middle. The spacing between steel pipe piles is 0.4m. Due to the small spacing between steel pipe piles, the skip excavation method is used for construction, and the drilling rig uses a 220mm diameter drill bit for geological exploration drilling rig construction.

2. Steel pipe pile construction process

Steel pipe pile process: measurement and layout → hole spacing positioning → in-place drilling → hole cleaning → installation and lowering of steel pipes → installation of grouting pipes → mixing cement slurry → injection of cement slurry → multiple pressurized grouting.

(1) Measurement and layout: Measurement and layout are carried out according to the spacing, row spacing and elevation required by the design;

(2) Hole spacing positioning: Use a plated drill to drill into the ground for positioning according to the designed hole diameter, spacing and row spacing;

(3) In-situ drilling: Place the drilling machine at the designated location and level it to prevent tilting; Drill the drill rod to the side of the drill bit, connect the water pipe to the drill rod, start the drilling machine and the water pipe, and drill slowly; every 2m of drilling, the drill rod needs to be connected until the designed effective depth is reached;

(4) Hole cleaning: Before injecting cement slurry, the hole is required to be cleaned to discharge the mud content in the hole. The thickness of the sediment at the bottom of the hole is required to be no more than 50mm;

(5) Installing and lowering the steel pipe: After the hole is cleaned, install the pre-made steel pipe in the hole in time. The steel pipe foundation is 200mm above the ground to facilitate the connection of the grouting pipe;

(6) Install the grouting pipe: The grouting pipe is directly connected to the steel pipe in the entry hole by the grouting machine. The interface is connected by threaded joints. Pay attention to the rubber sealing pad for sealing;

(7) Mixing cement slurry: The cement slurry is mixed by a special machine, and the water-cement ratio is controlled between 0.45 and 0.5. The mixed cement slurry is placed in a steel water tank and then grouting is performed by the grouting machine;

(8) Injection of cement slurry: The grouting pipe is connected to the grouting pressure gauge, the grouting pressure is 0.5Mpa, and the water-cement ratio is controlled between 0.45 and 0.5. After grouting, check the bottom of the pipe until the cement slurry stops flowing out of the pipe seal. Pull out the grouting pipe, seal the steel pipe port, and seal it until the cement slurry flows out of the outer steel pipe again;
(9) Multiple pressurized grouting: Because it is difficult to obtain the required flushing coefficient in one grouting, the grouting pressure is 0.5Mpa, and multiple intermittent grouting is required, generally three to five times, until the slurry turns over in the fine stone filling;
(10) The first grouting pressure is 0.4~1.0 Mpa, and it is maintained for 3 minutes to ensure that the pressure breaks the tape and the slurry is forced out of the pipe to fill the pile body. The second grouting pressure shall not be less than 1.5Mpa, and the interval between the two groutings shall not be less than 1.5~4 hours;
(11) The pile position deviation shall not be greater than 50mm, the pile diameter deviation shall not be greater than 4%, and the verticality shall not exceed 1%. (12) During the construction process, the construction records must be checked at any time, and the quality of each project must be assessed against the prescribed construction process. The focus of the inspection is on cement usage, pile length, pile diameter, grouting, pressure, stone grading, etc.;

Conclusion

The steel pipe piles construction process involves precise drilling, precise installation of steel pipes, and controlled multi-stage grouting operations to ensure the integrity of the structure. By strictly following the construction process and implementing comprehensive quality control, reliable and lasting foundation support can be provided for the project. The use of Q345 seamless steel pipes and advanced grouting technology can meet the high standards of construction efficiency and structural stability of modern buildings.

Steel pipe pile construction is a project with extremely high technical requirements. Its complete process includes site preparation, steel pipe pile processing, pile sinking construction, and quality acceptance. Through scientific construction organization and rigorous quality management, the bearing capacity and stability of steel pipe pile foundations can be significantly improved, providing a solid and reliable foundation guarantee for various engineering construction projects.

For construction units, mastering each key step of steel pipe pile construction and flexibly adjusting the process according to project needs are the key to ensuring construction quality and efficiency. If you have any questions about steel pipe pile construction, please leave a message to communicate with us, or contact our professional team for more technical support!