Mechanism of Bearing Capacity for Pile with Multi-Stepped Two Diameters Subjected to Vertical Load

Abstract

The purpose of this research is to clarify the bearing capacity mechanism of a pile with multiple stepped two diameters to be used in small or medium scale agricultural facilities. Model tests were conducted by driving multi-stepped type metallic piles into the dry sand. The following points about the multiple stepped two diameters pile were confirmed; i) it has higher bearing capacity than the conventional cylindrical pile, and ii) the longer the concave part of a pile, the higher will be its bearing capacity. Though qualitative, the interaction between the pile and the surrounding ground could be well predicted by DEM analysis. The progressive interaction of pile with the surrounding soil reached its maximum when the pile penetration reached about 8-12%. The mechanism could be explained by the DEM result that showed diagonal movement of sand particles at the concave part of the pile in the beginning, which then ceased gradually once shear failure progressed.