Construction process and purpose of fully automatic hydraulic pile driver

Construction technology of fully automatic hydraulic pile driver: pouring pile into hole → steel cage production → grouting pipe production → pouring pile cleaning hole → grouting pipe bonding → lowering steel cage → grouting construction after pouring pile concrete

Key points of construction

1. The preparation of grouting pipes involves the production of grouting pipes while manufacturing steel cages. The grouting pipe is made of black iron pipe with a diameter of 25mm, and the joint is connected by threads. The end is sealed by plugging with wires. The length of the grouting pipe is 55 centimeters longer than that of the steel cage. The bottom of the steel cage is 5 centimeters long, and the upper part is 50 centimeters higher than the concrete surface of the pile top, but it should not be exposed to the ground for protection. The grouting pipe is made into a grouting nozzle (usually referred to as a flower tube) at the bottom of 20cm. In this section, the drill bit evenly drills out four rows (four rows per row). Use grouting holes with a spacing of 3cm and a diameter of 3mm as grouting nozzles; The push pin is tightly plugged into the grouting hole, and an outer tube of the same diameter is sleeved on the outside. Both ends are sealed with tape to form a simple one-way device for the grouting nozzle: during grouting, the pressure on the grouting tube will cause the tire to split, and the push pin will be ejected. The cement slurry is pressed into the gravel layer through the grouting hole and the hole gap of the push pin. This device ensures that the concrete slurry will not block the grouting tube when pouring concrete.

2. The layout of the grouting pipes for the fully automatic hydraulic pile driver is symmetrically tied to the outside of the steel cage. After the hole is formed, it can be drilled under the steel cage. During the process of hoisting the steel cage, attention should be paid to the protection of the grouting pipe. The steel cage should not be twisted to prevent loosening of the grouting pipe at the threaded joint, and the concrete part should be added to the sprinkler head. When protecting the block, do not rub the hole wall to avoid blocking the grouting hole caused by tire rupture. Fill concrete according to specifications.

3. The selection of grouting pile position is based on past engineering practice, and in gravel layers, cement slurry has a significant impact area under working pressure. To prevent cement slurry from being discharged from weak environments during grouting, grouting piles should be completed 3-7 days after concrete pouring. There should be no drilling operations within a range of at least 8 meters around the pile, and the pile foundation concrete can be completed by filling this range.

4. When grouting the construction sequence, it is best to use the entire pile cap pile for grouting at once, grouting first, then constructing the surrounding pile position, and then constructing the middle pile; During grouting, two piles are used for cyclic grouting, which is the first pressure. The grouting volume of the first batch of A pipes is about 71% of the total amount (cement 111-114 tons). After compression, the other pipe of another pile is compressed, and then the B pipe is continuous with the first pile of the first pile. The B pipes of two piles can ensure a time interval of 30-60 minutes between the two pipes, and the cement slurry diffuses in the gravel layer. Construction records should be kept during grouting. The recorded content should include construction time, grouting start and end time, grouting volume, as well as abnormal situations and handling measures.