Influence Of Soil Plug On The Vertical Bearing Capacity Of The Single Pipe Pile

In this paper, the author summarizes methods used to analyze vertical bearing capacity of the pipe pile firstly. Then, the role that the soil plug plays in pipe pile is studied to evaluate influences of soil plug on vertical bearing capacity.We study the problem mentioned above by finite element analysis combining with model test. In finite element analysis, the interaction between the pile and soil are simulated by interface to make results closer to the engineering practice. The Hardening-Soil model and the Mohr-Coulomb model are chosen respectively to do the analysis. Then the calculated results are compared with the model test results. We find that results based on Hardening-Soil model are better than that based on the Mohr-Coulomb model in this case. Numerical results show good agreement between the finite element analysis and the model test. That means the numerical results is dependable.Based on FEM analysis, we can find that the bearing capacity of open-ended pile coming from inner frictional resistance, external frictional resistance and point resistance. The external friction resistance is mobilized and reached the limit state at first. At the same time, the point resistance is also mobilized with the displacement increment. The point resistance got to the limited value at the end of loading. With the increment of displacement, the inner frictional resistance provided by soil plug exerts gradually, and it does not get to the limit state at the end of loading.The parameterβnot only relate to the ratio of soil plug length to inner radius of pipe pile, but also the displacement of pipe pile. Basically,βchanges along soil plug length reflect the fact thatβis affected by displacement. In consequence, it is necessary to consider the allowable displacement of pile when calculate the capacity of soil plug.