effect of cone diameter on determination of penetration resistance using a fcv

The cone penetration test (cpt) and dynamic cone penetration test (dcpt) are the most two efficient in-situ tests in geotechnical practice. due to experimental test limitations, it is sometimes impossible to use cone penetrometer (cp) with standard dimensions via physical modeling, and the use of smaller size of cp is needed. the objective of this study has been to investigate the size effect of cpt on penetration resistance. the sand material collected from a coastal area of the caspian sea in babolsar city. frustum confining vessel (fcv) was used due to its ability in high stress physical modeling and forming approximately linear distributed stress in depth, which makes it one of the most suitable physical modeling apparatus for investigating dcp and cpt. in this research, two different cps, a standard dimension (35.7 mm) and a smaller size (24 mm in diameter), and one standard dcp were employed to be tested in babolsar sand. results demonstrate that the cone resistance (qc) and sleeve friction (fs) values are greater in the minicp compared to the standard cone. this trend goes more notable when either of relative density or vertical effective stress increases. however, the ratio of cone resistance or sleeve friction, for minicpt to standard cpt is constant with various values of vertical effective stress or relative density. accordingly, the cone resistance and sleeve friction ratio for minicpt in comparison to cpt are greater almost 1.23 and 1.18, respectively. also, the correlation values between qc with sand parameters, obtained from laboratory tests, relative density (dr), porosity (e), and with dynamic cone penetration index (dpi) have been investigated and presented. © 2021, iran university of science and technology.