Model Test Study For Vertical Bearing Of Variable Cross-section Pile

As the application of pile foundation in practical engineering increases rapidly, thebearing capacity, deformation and project construction cost of pile foundation has become avery interesting question in the construction area. In this context, many researchers andtechnicians takes continuous explore and innovation towards the research and application ofpile foundation. Many types of pile are constantly emerging. The variable cross-section pileis the one. It has gained significant social and economic benefits in many ways,such asdecreasing settlement, increasing safety and reducing construction costs.However, therelevant theory studies achievement about this new type of pile right now is relatively less.This thesis, combined with the key research project in Ministry of Railways in2009—research on design method and bearing behaviour of large diameter variablecross-section pile in soft soil area（Project No.2009G010-D）, carry on half pile modelexperiment research. A set of apparatus of foundation physical model are developed andutilized to conduct the model tests. Based on the former pile experimental data and the resultof this model test, we analyze the load-settlement curve,the distribution of axial force andlateral friction as well as the resistance of soil on pile end and on the position with variablecross section. The differences between uniform pile and non-uniform pile are compared. Andthen we study the vertical bearing behaviour of variable cross-section piles and the influenceof the ratio of variable diameter on vertical bearing characteristic.In this paper, the model test is used as a major means and the finite element numericalsimulation analysis is carried out as the auxiliary means.The bearing performance of thevariable cross-section pile is simulated by finite element analysis software ANSYS10.0. Theresults of the numerical simulationand and the model test are compared. And then we makefurther researches and summarize the load transfer mechanism of the variable cross-sectionpile.Finally, the calculating formula of bearing capacity and settlement of variablecross-section pile is preliminarily given.