M. Zare, A. Eslami,
Volume 12, Issue 4 (12-2014)
Physical modeling for study of deep foundations can be performed in simple chambers (1g), calibration chambers (CC),
and centrifuge apparatus (ng). These common apparatus face certain limitations and difficulties. Recently, Frustum Confining
Vessels (FCV) have been evolved for physical modeling of deep foundations and penetrometers. Shaped as the frustum of a
cone, this device applies steady pressure on its bottom and creates a linear stress distribution along its vertical central core.
This paper presents the key findings in FCV, as developed in AUT. The FCV has a height of 1200 mm, with top and bottom
diameters of 300 and 1300 mm, respectively. By applying bottom pressure up to 600 kPa, the in-situ overburden stress
conditions, equivalent up to 40 m soil deposits, become consistent with the embedment depth of commonly used piles.
Observations indicated that a linear trend of stress distribution exists, and this device can create overburden stress in the
desired control volume along the central core. Moreover, a couple of compressive and tensile load tests were performed on
steel model piles driven in sand with a length of 750 mm, and different length to diameter (L/D) ratios between 8-15.
Comparison between measured and predicted ultimate capacity of model piles performed in FCV demonstrate a suitable
conformity for similar confinement conditions in the field. Therefore, the FCV can be considered as an appropriate approach
for the investigation of piling geotechnical behavior, and the examination of construction effects.