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

In this paper, the development history of the pre-stressed concrete pipe pile was reviewedand the current pile-foundation design theory and calculation methods were also introduced.Vesic's solution to the problems of hole expansion including the cylindrical cavity expansionand spherical cavity expansion were introduced and then applied to the analysis of soilsqueezing effect of pile driving. Used the unique soil plugging effect of open-end pipe pile asthe study object, the formation process of soil plugging was analyzed, and the conclusionshowed that wedge body would be formed at the end of pipe while driving pipe. The wedgebody played an important role in the formation process of soil plugging and couldn't beignored. Then considering the effect of the wedge body, soil plugging formula was establishedand the core failure mode of the soil plugging was also raised.Pre-stressed concrete pipe piles are interactional system of pre-cast concrete piles and soilmass. In this paper, the characteristics, the applicable geological conditions and the existingproblems of the pre-stressed pipes were discussed and the advantages and disadvantages of thenormal safety factor method for pile calculation in Code were evaluated. On the basis of pileloading transmission mechanism and actual project data, existing vertical load calculationmethod and formula of pre-stressed pipe pile in Code were analyzed and improved by using thefinite element numerical simulation software.In addition, concerning there isn't relatively perfect theoretical system in calculating thesettlement deformation, so it leads comparatively large deviation between the calculatedvalues and the measured values. In this paper, according to the actual observation data, thecalculation methods of the settlement deformation were discussed and analyzed, and the conclusion would provide a more rational design method for the designers. The theoreticalsystem of the pre-stressed concrete pipe piles was improved further, and that would graduallylead the conversion of the structural design from the capacity control method to thedeformation control method by which pre-stressed pipe piles would be better used and obtainmore economic benefits.