Babak Ebrahimian - Geotechnical Division, Department of Infrastructure, Petroleum Industry Research Engineering Company (PIRECo.), Tehran, Iran;
Vahid Movahed - Geotechnical Division, Department of Infrastructure, Petroleum Industry Research Engineering Company (PIRECo.), Tehran, Iran;
Aida Nazari - Geotechnical Division, Department of Infrastructure, Petroleum Industry Research Engineering Company (PIRECo.), Tehran, Iran;

In the current study, the results of numerous piezocone penetration tests performed in various locations of South Pars Gas & Oil field, Persian Gulf, Iran, were used to evaluate undrained shear strength of marine clay of the site using cone factors. Comparison of variation of undrained shear strength and PCPT results in depth was shown that cone factor can be a useful parameter to determine undrained shear strength, indirectly, from cone tip resistance. It was observed that there is a relatively strong correlation between undrained shear strength of soil and cone tip resistance. With studying the variations of cone factors in depth, an average value of Nk=18 and Nkt= 21 were proposed for South Pars field. In addition, the results were demonstrated the importance of taking the effect of pore water pressure into account for determining cone factor. Moreover, it was showed that cone factor is rather dependent to over-consolidation ratio of soil. As over-consolidation ratio increased both cone factors decreased with a descending rate

piezocone penetration test, undrained shear strength, cone factor, marine clay, over-consolidation ratio,South Pars, Persian Gulf