VISUALIZATION OF VERTICAL BEARING CAPACITY ON STEEL-PILE-SHEET-PILES USING X-RAY CT SCANNER

A new sheet-pipe-sheet-pile from a simple idea in which two steel pipe piles are connected by H-steel section welded on them to form what is known as "H-jointed SPSP". Two connected piles are driven simultaneously thus reducing the number of driven piles. To evaluate the vertical bearing capacity of a driven pile, it is important to clarify the failure mechanism of ground around tip of the driven pile due to vertical loading., However, the generation mechanism of vertical bearing capacity on the SPSPs, called "a plug effect of a pipe pile", has been still researched. The objective of this paper is to visualize the behavior of ground around the tip of the SPSPs due to vertical loading using X-ray computed tomography (CT) scanner and to evaluate the plug effect of SPSP. Vertical-loading tests in the model ground using the conventional SPSP and H-jointed SPSP models were performed in this research. Plug effect and mechanism of vertical bearing capacity on SPSPs were evaluated three dimensionally without any destruction of the model ground.