The Analysis Of Vertical Bearing Capacity Of The Pre-stressed Concrete Pipe Pile

Pre-stressed concrete pipe pile is widely used in the 80's of 20th century, and it is a special type of prefabricated concrete pile. This type of pile has many advantages, such as simple technique, better quality, fast construction low cost and convenient detection, so it has been widely used in geotechnical engineering. Though with the above merits, its design theory and construction technique need to be further perfected.The key element in the design of pipe piles is the determination of the vertical bearing capacity of a single pile. However, till now, there are only a few empirical formulas about the computation of the vertical bearing capacity of the pre-stressed concrete pipe pile in the worldwide and there is no leading method in China. If the bearing capacity of a single pile is determined based on the empirical formula of the current design code, generally it will be much lower than that by static load test. In the paper, based on the soil plugging effect and soil compaction effect, the author analyzed the behavior of stress and its unique mechanism of bearing in details. It also illustrates that the soil plugging effect and soil compaction effect is the main reason for the enhancement of the vertical bearing capacity of a single pre-stressed pipe pile.Based on the influence of soil compaction effect and soil plugging effect on the vertical bearing capacity of PHC, this paper count and conclude large quantity cases of static load test results and analysis the difference between the practical and designing bearing capacity, then puts forward a new method about the calculation of the vertical bearing capacity of a single pile..Through the contrast of calculation result and measured result, the author verifies the practical significance of the new method. It hopes this paper will supply some reference value and helpful for the design of PHC in the later.These researches of the design method and the construction technique of prestressed concrete pipe pile are of important practical significance.