Advantages and disadvantages of phc prestressed high strength concrete pipe pile

1.PHC pipe pile has lower price than bored pile, convenient procurement and transportation, and a set of mature manufacturing technology.

2. The construction speed is fast and the pile pressing is convenient. According to the specific parts, techniques such as hammering, static pressure at the top and pressure keeping can be adopted. Generally, the pile of about 30 meters is divided into three sections, and the time from positioning, correction, pile pressing and pile connection is about 15-25 minutes. A rock-socketed cast-in-place pile of about 30 meters generally takes 24 hours.

3. The bearing capacity is intuitive, and can be easily determined according to the crane frame or static pressure reading.

4. After 4.PHC pipe pile is pressed for 7 days, static pressure test can be carried out. It takes 28 days or even longer to fill the pile. To sum up, its biggest advantages are low cost and fast construction speed, which can save the construction period and speed up the project construction.

Disadvantages:

1.PHC pipe piles are divided into thin-walled piles and thick-walled piles. Thin-walled piles can't be used as uplift piles, and when they are uplift piles, they can't be used because of some local restrictions. (Jiangsu clearly stipulates that uplift piles are not allowed) PHC pipe piles, as uplift piles, have sufficient bearing capacity, including joint strength, but the connection with pile caps should be properly handled. Generally, the core is poured within 2-3 meters of the pile top, and the core column is placed to strengthen the connection.

2.PHC pipe pile has obvious soil squeezing effect when piling. If there are buildings or sensitive municipal pipelines around, its use will be restricted, otherwise it will easily lead to cracks in the surrounding buildings, and the general concession distance is 20-30 meters.

3. In buildings with basements, PHC pipe piles are usually driven first and then excavated. (There are also excavation and piling. Piling can also be done after excavation, but on the premise that there must be slope support around. If the surrounding area needs support, you can't dig first and then pile up. Otherwise, the extrusion stress in the center can't spread around, and the support will go wrong. Some foundation pit collapses are caused by soil squeezing. ) In the process of excavation, pipe piles are prone to tilt, crack and fracture. It is very troublesome to correct and reinforce the pipe pile. Generally, anchor static pressure pile or core grouting is used for treatment. The reason for this situation is that the shear bearing capacity of pipe pile is very low, and it is easy to break, tilt and crack with the deformation of soil.