The purpose of steel pipe pile construction is to transfer the load of the upper building to the deeper soil layer with a stronger bearing capacity or to compact the weak soil layer to improve the bearing capacity and compactness of the foundation soil. Therefore, the construction of pipe piles must be ensured. quality, otherwise the building will be unstable. Pipe pile construction steps are:

1. Surveying and setting out: The surveying engineer sets out the piles according to the designed pile position map and marks the piling points with wooden piles or white ash.

2. The pile driver is in place: The pile driver is in place, align the pile position, and carry out construction vertically and stably to ensure that it does not tilt or move during construction. The pile driver is positioned on the pile position, hoist the pipe pile into the pile driver, then position the pile end at the center of the pile position, raise the mast, and correct the level and pile center.

3. Welding pile tip: Take the commonly used cross pile tip as an example. The cross pile tip is placed at the pile position after verification, and the bottom end plate of the section pipe pile is welded to its center. The welding is done using CO2 shielded welding. After welding, The pile tips are painted with anti-corrosion asphalt.

4. Verticality detection: Adjust the extension length of the oil plug rod of the pile driver leg cylinder to ensure that the pile driver platform is level. After the pile is 500mm into the soil, set up two theodolites in mutually perpendicular directions to measure the verticality of the pile. The error should be no greater than 0.5%.

5. Pile pressing: The pile can only be pressed when the concrete strength of the pile reaches 100% of the design strength, and the pile remains vertical without abnormality under the verification of two theodolite. During pile pressing, if there are serious cracks, tilt, or sudden deflection of the pile body, the pile can be pressed. Construction should be stopped if phenomena such as movement and drastic changes in penetration occur, and construction should be resumed after handling them. When pressing the pile, pay attention to the speed of the pile. When the pile enters the sand layer, the speed should be appropriately accelerated to ensure that the pile tip has a certain penetration ability. When the bearing layer is reached or the oil pressure suddenly increases, the pile should Slow down the pressing speed to prevent pile breakage.

6. Pile connection: Generally, the length of a single-section pipe pile does not exceed 15m. If the designed pile length is longer than the length of a single-section pile, the pile connection is required. Generally, the electric welding process is used to weld the pile connection. During welding, two people must weld symmetrically at the same time. , the welds should be continuous and full, and there should be no construction defects. After the pile connection is completed, it must be inspected and accepted before piling construction can continue.

7. Pile feeding: When the pile is pressed to 500mm from the filling surface, use a pile feeding device to press the pile to the design elevation, and increase the static pressure appropriately. Before feeding the pile, the depth of the pile feeding should be calculated according to the design requirements, and the pile feeding depth should be calculated according to the design requirements. Mark the device. When the pile is delivered to about 1m from the design elevation, the surveyor instructs the pile driver operator to reduce the pile driving speed and track and observe the pile delivery situation. When the pile delivery reaches the design elevation, a signal is sent to stop the pile delivery.

8. Final pile: Double control of pressure value and pile length is required during the construction of engineering piles. When entering the bearing layer, pile length control is the main method, and pressure value control is the supplement. If there are any abnormalities, the design unit must be notified for handling.