What Precautions Should Be Taken During the Construction of Industrial Steel Pipe Piles

The construction quality of steel pipe piles is crucial to the stability of the building. Therefore, attention must be paid to certain details during the construction process. The main precautions for steel pipe pile construction are as follows:

1. Before construction, surveying and setting out must be conducted by professional surveyors. All axis lines and pile positions must be set out and verified by the supervisor before construction can begin.

2. After the pile driver is in place, the pile frame should be adjusted to ensure it is vertical and stable.

3. For steel pipe piles ready for lifting and driving, first check whether the quality of the pile body meets the specifications. Mark the length on the pile body in meters, indicating the length from bottom to top, to observe the penetration depth and record the number of hammer blows per meter.

4. After the steel pipe pile is aligned and in place, use a plumb line to repeatedly check its alignment on both sides, ensuring the hammer, cap, and pile are all on the same straight line. Off-center driving is strictly prohibited.

5. During the driving process, if the steel pipe pile body deviates from its normal position, it should not be forcibly corrected mechanically, nor should it be corrected while driving. If the deviation is within the allowable range specified in the standards, the steel pipe pile body should be avoided for correction to prevent cracking. If the verticality deviation is found to be greater than the standard requirements, the cause should be identified first, and the steel pipe pile section should be pulled out. After backfilling and compacting the pile hole with sand, driving should be resumed at the same point.

6. When steel pipe piles need to be extended, driving can be stopped when the pile head has sunk to 500mm-800mm above the ground, and the previous pile section can be spliced. When splicing, a guide hoop (pile clamp) should be installed at the lower pile head to ensure the upper pile section is in place. The upper and lower pile sections should be kept straight. Then, the pile clamp should be removed, and the upper and lower end plates should be cleaned with a wire brush before welding.

7. When driving piles in thick layers of sand or silty clay, it is advisable to drive a single steel pipe pile continuously in one go until the hammer is withdrawn. Because the soil has a high consolidation force when driving piles in this type of soil layer, if driving is paused for a period of time, the soil's consolidation and recovery will prevent the piles from being driven deeper. Forcing driving will result in the pile head being damaged.

8. When the steel pipe pile reaches the designed bearing layer or achieves the designed penetration depth, the hammer can be withdrawn. After withdrawing the hammer from the steel pipe pile, a timely measurement record should be made, and the verticality deviation of the pile should be measured with a plumb line, accurately recording the deviation in the east, south, west, and north directions and its percentage. For any doubtful pile numbers, a plumb line or light should be used to probe into the hole, and the deviation should be compared with the length of the supporting pile. Any problems found should be reported immediately.

9. When the pile top is driven close to the ground and needs to be driven, the verticality of the pile should be measured, and the quality of the pile top should be checked before driving the pile. The pile driver should be matched with the size of the steel pipe pile. Burlap sacks or cardboard should be added as a pad between the pile driver and the pile head of the steel pipe pile. In order to ensure the single pile bearing capacity of the steel pipe pile, the penetration value of the driven pile should be tightened, generally 80% of the penetration when the pile is not driven.