Study Of Theory For DX Pile Settlement

DX pile is a new developing kind of pile type in recent years, because of its load-carrying plates, it causes the pile load transfer mechanism differently compare to the diameter pile, whether in the bearing capacity and settlement of deformation, DX pile are greatly improved and enhanced, it has commonly used in many engineering fields, and has obtained very good economic benefits and engineering effect. To further promote the DX pile to apply in the high speed-rail and other major project, the study of theory for DX pile settlement is especially important. This paper not only based on the measured data in the cast-in-situ and apply Geddes and mindlin sulotion to caculate DX pile settlement; At the same time based on the setthlement theory of diameter pile in the domestic and foreign, to deeply discuss and analyse the DX pile settlement characteristics,the main contentsas follows:Firstly,take a jiangsu project for example, analyse the body axial force mechanism, friction resistance of pile shaft, end bearing and plate capaciy;The test results show that the DX pile enhanced the bearing capacity and reduced the settlement of deformation of pile foundation.Secondly,based on summaring many engineering test site in recent years to hypothetically pile body stress of DX pile and diameter pile,and then as Geddes solution and mindlin solution a basis, apply layerwise summation method to caculate DX pile settlement, and compare to diamater pile settlement with the same load conditions (settlement ratio a). Througth discussing the pile length, pile diameter, the load-carring plate diameter and the distribution shape of the friction resistance of pile shaft impact on the settlement ratio. In general, the ratio a is range from0.60to0.80.Thirdly, deducing shear displacement method of DX pile settlement from diameter shear displacement method, and based on this research analysing how the load-carrying plate location and the number of plate influence single DX pile settlement.Fourthly, caculate the interaction coefficient of two DX pile with the variation of s/D, rigidity confficient (K=EP/ES), the location of load-carrying plate, the number of plate and the length-diameter ratio of pile varied, and then put forward a formula for group DX pile settlement; to full-scale model test for DX pile cast in-situ, used this formula to caculating the settlement of group DX pile, the results is very closer to the test value.