A Numerical Study and Simulation of Vertical Bearing Performance of Step-Tapered Pile Under Vertical and Horizontal Loads

In the present work, a numerical simulation of vertical bearing performance of step-tapered pile was carried out. The effects of pile geometry and the soil profile on the vertical bearing capacity of the step-tapered pile under vertical and horizontal loads were studied. Numerical results indicate that increasing diameter (D) of the enlarged upper part of step-tapered pile can increase its vertical ultimate bearing capacity when the other geometric parameters remain unchanged. When the distance (L) between the upper enlarged surface and the top of step-tapered pile is within a threshold value, the increase in the distance (L) can improve the vertical ultimate bearing capacity of the pile. Also, increasing the length (H) of the enlarged upper part of step-tapered pile can significantly bring up the vertical ultimate bearing capacity of the pile. Strengthening the soil around the step-tapered pile and at the pile tip can increase the ultimate bearing capacity of the pile. The distribution of axial force changes abruptly at the lower end of the enlarged part of the step-tapered pile in saturated clay, silty clay and sandy soil, and the axis force at the lower end of the enlarged part is greatly attenuated.