Design and fabrication of frustum confining vessel apparatus for model pile testing in saturated soils

Offshore and marine engineering has developed rapidly, mainly due to the growing demand from the oil and gas industry for research and construction in deep-sea areas. Consequently, the need for research on the behavior of piles in saturated and partial saturated soils has also arisen. Frustum confining vessel (FCV) is a relatively new device for physical modeling, which was first introduced in 1996. In this research, a comprehension study was conducted on the optimum dimensions of the FCV apparatus with the aim of considering fabrication. To assess the performance of the models, ABAQUS software was adopted. By comparing the performance of the generated models, the optimum dimensions were selected and the apparatus was fabricated. All the flange connections were sealed to be able to conduct pile tests in saturated soils. The present apparatus is the first FCV device built with the capability of testing in saturated soils, to the best of the author’s knowledge. Finally, to assess the performance of the device, the axial bearing capacity of a multi-helix pile in both moist and saturated conditions with different relative density was studied through experiments. Results indicate that the present FCV apparatus could effectively model the scaled condition of the soil and is capable of testing in saturated conditions. Results indicate that the saturation condition affects both the bearing capacity of pile and the initial slope of the load–displacement curve.