Views: 2 Author: Site Editor Publish Time: 2025-01-14 Origin: Site
The purpose of steel pipe pile construction is to transfer the load of the upper building to the deep soil layer with a strong bearing capacity or to compact the weak soil layer to improve the bearing capacity and density of the foundation soil. Therefore, the quality of steel pipe pile construction must be guaranteed, otherwise the building will be unstable. The steps of steel pipe pile construction are:
1. Surveying and laying out: The surveying engineer lays out according to the designed pile position map and marks the pile driving points with wooden stakes or white lime.
2. Pile driver in place: The pile driver is in place, aligned with the pile position, and vertically and stably constructed to ensure that it does not tilt or move during construction. The pile driver is in place on the pile position, the steel pipe pile is hoisted into the pile driver, and then the pile end is positioned at the center of the pile position, the gantry is lifted, and the level and pile center are corrected.
3. Welding pile tip: Taking the commonly used cross pile tip as an example, the cross pile tip is placed at the verified pile position, and the bottom end plate of the section steel pipe pile is welded to the center with it. CO2-shielded welding is used for welding, and the pile tip is painted with anti-corrosion asphalt after welding.
4. Verticality detection: adjust the extension length of the oil plug rod of the pile driver's outrigger cylinder to ensure that the pile driver platform is horizontal. After the pile is 500mm into the soil, use two theodolites set up in perpendicular directions to measure the verticality of the pile. The error should not be greater than 0.5%.
5. Pile pressing: The concrete strength of the pile reaches 100% of the design strength, and the pile can be pressed only when it is kept vertical and without abnormalities under the calibration of two theodolites. If there are serious cracks, tilts, sudden deviations, and sudden changes in penetration during pile pressing, construction should be stopped and construction can be resumed after proper treatment. Pay attention to the speed of pile pressing when pressing piles. When the pile is entering the sand layer, speed up the pile pressing speed appropriately to ensure that the pile tip has a certain penetration ability. When reaching the bearing layer or the oil pressure suddenly increases, the pressing speed should be slowed down to prevent broken piles.
6. Pile connection: Generally, the length of a single steel pipe pile does not exceed 15m. If the designed pile length is greater than the length of a single pile, it is necessary to connect the piles. Generally, electric welding is used to weld the piles. Two people should 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 needs to be accepted before the piling construction can continue.
7. Pile delivery: When the pile is pressed to 500mm from the fill ground, the pile driver is used to press the pile to the design elevation, and the static pressure is appropriately increased. Before the pile is delivered, the pile delivery depth should be calculated according to the design requirements, and a conspicuous mark should be made on the pile driver. 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 until the pile is delivered to the design elevation, and a signal is issued to stop the pile delivery.
8. Final pile: During the construction of engineering piles, it is required to control the pressure value and pile length. Entering the bearing layer is mainly controlled by the pile length, supplemented by the pressure value control. If there is any abnormality, the design unit needs to be notified for processing.