Pile-soil Interaction And Vertical Bearing Capacity

With the high-speed construction of city and the erection of high-rises, the cost offoundation improvement is doubling. Moreover, the pile foundation design is more demanding.Pile-soil interaction, the choice of bearing capacity formula adaptable to special area and how toascertain the suitable pile length in order to decrease the cost are the subjects presented to theresearchers and engineers. Based on facts, with Xi'an urban district as the example, a newapproach that consists of the static loading test of the same-sized friction piles and the 3Dsimulation study has been presented. The major contents of this paper are:The static loading test research of same-sized friction piles. In a certain site, according to thesingle cast-in-place pile static loading test and the acquired stress data, the graphs on the pile-soilinteraction and the ultimate bearing capacity of single piles have been drawn. Furthermore, theuniversal features of the single pile load transferring in the loess area in Xi'an have beenconcluded.3-D simulation. Based on the stratum constitution of the same-sized piles, appropriate premiseand boundary condition. 3-D simulation physical model has been founded. This method isproved reliable by the agreement between the result of simulation and that of corresponding tests.In this way, 3-D simulation can be regarded as a good method to analyze the pile-soil interaction.With some typical loess stratum analyzed in Xi'an, the major factors which influence the singlepile load transferring and settlement feature have been founded, moreover, the compressedmagnitude of piles has been researched. Based on a multitude of simulations, that the optimalrange of pile-soil relative displacement is 3.0-9.0mm has been concluded.Based on the 3-D simulation and the specific stratum constitution, the optimal pile length canbe ascertained step by step. In addition, the quantitative relation between the ratio pile length topile diameter L/D and pile-soil relative stiffness Ep/E has been summed up. And single pilebearing capacity formula has been proposed.