Automatic hydraulic pile driver construction technology: pouring pile entry hole → steel cage production → grouting pipe production → pouring pile cleaning hole → grouting pipe combination → lowering steel cage → grouting construction after pouring pile concrete

Construction points

1. Preparation of grouting pipes The grouting pipes are produced at the same time as the steel cage is manufactured. The grouting pipe is made of a black iron pipe with a diameter of 25mm, the joint is connected by thread, and the end is blocked and sealed by a wire. The length of the grouting pipe is 55 cm longer than the length of the steel cage. The bottom of the steel cage is 5 cm long, and the upper part is 50 cm higher than the concrete surface of the pile top, but it should not be exposed to the ground for protection. The grouting tube is made into a grouting nozzle (usually called a flower tube) at the lowest part of 20cm. In this part, the drill bit drills four rows evenly (four rows per row). The grouting holes with a spacing of 3cm and a diameter of 3mm are used as grouting nozzles; the push pin tightly plugs the grouting hole, the outer tube of the same diameter is sleeved on the outside, and the two ends are sealed with tape, so that the grouting nozzle forms a simple one-way device: when grouting, The pressure in the grouting pipe will become the tire split, the push pin will be ejected, and the grout will be pressed into the gravel layer through the grouting hole and the hole of the push pin. This device ensures that the concrete slurry will not block the grouting pipe when the concrete is poured.

2. Arrangement of the grouting pipe of the automatic hydraulic pile driver The two grouting pipes are symmetrically tied to the outside of the steel cage. After the hole is formed, it can be drilled under the steel cage. In the process of hoisting the steel cage, attention should be paid to the protection of the grouting pipe. The reinforcement cage should not be twisted to avoid loosening of the grouting pipe at the threaded joint, and the concrete part should be added to the sprinkler head part. When the stopper protects, do not rub the hole wall, so as not to block the grouting hole caused by the tire rupture. Fill concrete according to specifications.

3. Selection of the location of grouting piles According to the past engineering practice, in the gravel layer, the cement slurry has a larger area of ​​influence under the working pressure. In order to prevent the cement slurry from being discharged from the weak environment during grouting, the grouting pile should be completed 3~7d after the concrete is poured. There is no drilling operation within at least 8m around the pile, and the pile foundation concrete can be completed by filling in this range.

4. Grouting construction sequence When grouting, it is best to use the entire pile cap pile for one grouting, first grouting, then construct the surrounding pile position and then construct the middle pile; when grouting, the two piles are used for circular grouting, that is, the first pressure. The grouting volume of pipe A of the first pile is about 71% of the total (cement 111-114t). After pressing, the other pipe of the other pile is pressed, and then the B pipe is continuous with the first pile of the first pile. The B pipe of the two piles can ensure that the time interval between the two pipes of the two pipes is 30-60 minutes, and the cement slurry is diffused in the gravel layer. Construction records should be carried out at the time of grouting. The record should include construction time, grouting start and end time, grouting volume, abnormal conditions and treatment measures.