What data do you need to do in pile foundation construction? The pile is a prestressed pipe pile.

Pre-stressed pipe pile foundation construction needs to make the following preparations:

1. The equipment needs to be selected according to the regulations. Pile hammer can be selected from drop hammer, steam hammer, diesel piling hammer and vibration hammer. Drop hammer is generally made of cast iron, and there are two kinds of hammer: piercing hammer and dragon gate hammer. It uses rope or wire rope to be lifted to a certain height by hoist along the guide rod of pile frame through hook, and then falls freely and hits the pile top. Steam hammer is a piling machine powered by high-pressure steam or compressed air. There are two kinds of single-acting steam hammer and double-acting steam hammer.

Pile frame is the equipment that supports the pile body and the pile hammer, guides the direction of the pile, keeps the stability of the pile, and ensures the impact of the pile hammer in the required direction. Pile frame is generally composed of chassis, guide rods, lifting equipment, poles, etc. According to the pile length, pile hammer height and construction conditions, the pile frame is selected and the pile frame height is determined.

2. Confirmation of piling sequence. The piling sequence directly affects the quality of pile foundation and the construction speed. The piling sequence should be reasonably determined according to the pile density (pile spacing), pile specifications and length, pile design elevation, working face layout and construction period requirements. According to the density of piles, the piling sequence is generally divided into three types: driving one by one, driving from the middle to all sides and driving from the middle to both sides.

3. piling. When the pile driver is in place, the pile frame should be vertical and stable, and the center line of the guide rod is consistent with the piling direction. When the pile starts to hit people, the falling distance of the hammer should be controlled, and short-distance percussion should be adopted; After the pile is buried to a certain depth and stabilized, it shall be driven according to the specified falling distance.

The principle of piling is heavy hammer and low blow, so that the impact of the pile hammer on the pile head is small, the rebound is small and the pile head is not easy to be damaged. Most of the energy is used to overcome the friction between the pile and the soil and the resistance at the pile tip, and the pile can sink into the soil quickly.

4. Technical standard for piling. When the final penetration of end-bearing pile is not greater than the penetration value specified in the design, the design elevation of pile end can be used as a reference; When the pile end elevation of friction pile reaches the elevation range specified in the design, the penetration can be used as a reference. The deviation of driven piles must conform to the relevant provisions of quality control. Whether the bearing capacity of the pile meets the requirements should be tested.

Piling is a concealed project, and each pile should be observed and recorded during construction, which is the basis for quality inspection during project acceptance. The control of piling quality includes two aspects, one is to control the elevation, and the other is to control the deviation of piling without damaging the pile top and pile body.

Piling is the construction of concealed works, which should be observed and recorded well, including the speed of piling into the soil, the distance of falling hammer, the number of blows per minute, etc. , as the basis for identifying the quality of the pile when accepting the project.

Extended data:

Requirements for pile foundation construction:

1, pile hammer selection. When choosing a pile hammer, we must fully consider the shape, size, weight, buried depth, structural form, soil quality and weather conditions of the pile, and master the characteristics of various hammers. The tamping energy of pile hammer must overcome the penetration resistance of pile, including pile tip resistance, pile side friction resistance and energy loss caused by pile rebound.

If the energy of the pile hammer cannot meet the above requirements, it will cause local buckling of the pile head, and it is difficult to send the pile to the design elevation. In view of the soft and hard soil layer in this project, a 8t steam hammer is selected.

2. Selection of pile frame. The setting, installation and preparation of pile frame have great influence on piling efficiency. The pile frame adopts D-308S crawler walking pile frame, which is flexible to move and convenient to use. The walking mechanism is crawler type, which has relatively low requirements on the road surface.

3. Construction organization design and pile location arrangement. According to the geological conditions and foundation geometry of the piling construction area, the piling sequence is reasonably selected and preventive measures are taken for the surrounding buildings. According to the pile foundation construction drawing, set out the pile position.

4. Stacking and lifting. Generally, pipe piles need to be designed with two fulcrums (Figure 1), and their lifting points should meet the position requirements shown in Figure 2. Stacking requires mats (wooden mats). Vibration and collision should be avoided during lifting and transportation of pipe piles.

5. Determination of pipe pile age. The interval between pipe pile manufacturing and piling construction should be as long as possible, and the concrete strength should be above the standard value of design strength grade (if it is manufactured in a factory, it is generally delivered at 80% of the standard value of design strength grade). Therefore, a certain number of piles should be piled on site to meet the strength requirements of pipe piles according to the principle of "field first and piles later".

6. Check and arrange. Before the construction of pipe piles, check them one by one, that is, check whether there are any serious quality problems in concrete piles, and clean up both ends of the pipe piles. When the welding surface is polluted by paint impurities, clean it up.

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