Driving effect of PHC pipe piles

Both the soil properties and the mechanical characteristics of piles are affected by the driving effect of PHC pipe piles. Based on the old channel ground improved by PHC pipe piles at a power plant, the driving effect of PHC pipe piles is tested and analyzed. From the blow counts of PHC pipe piles during driving, the characteristics of driven PHC pipe piles are analyzed. Using the in-situ tests such as the static cone penetration tests, the standard penetration tests, and the measuresment of pore water pressure and lateral displacement, the effect of driving PHC pipe piles on their surrounding soil is investigated. It is shown that the blow counts of driven piles closely relate with the soil properties. The ratio of plug length to pile length is about 22%³5%, and the thinner the pile pipe wall, the greater the plug effect. During the driving process, there is large effect of soil squeezing, and it not only produces high excess pore water pressure, but also causes compaction of soil during pore water pressure dissipation and reduces the possibility of liquefaction. The lateral frictional resistance is enhanced by about 80% after driving, and it can improve the bearing capacity of piles.