Scale Effect Aspects for Correlation CPT Data in Foundation Analysis and Design

The cone penetration test (CPT) is the most applicable In-situ tests in geotechnical practice, because it is simple, fast, reliable, and economical nature. The scale effects between the pile toe resistance and CPT cone is studied by different researchers, so the effects of these factors are not taken in creating a relation between CPT sleeve friction and pile shaft resistance. The main purpose of this research is studying these effects on shaft resistance . The shear strain due to CPTsounding and pile load tests were studied and the scale effect aspects between CPT and pile related to the shear strain levels. Excess pore pressure effects in fine grained soils generated due to rate of penetration was individually considered.
Database consists of 42case histories of pile load tests including the CPT profile, derived from different sites have been used to evaluation of the current approaches. In this paper the proposed method for determining the shaft bearing capacity, with considering scale effects was evaluated and compaired with four methods including: Clisby et al 1978.,Tumay and Fakhroo 1981, Price and Wardle 1982, and Takesue et al 1998.The results of analysis by proposed method demonstrate good accuracy in comparison with the other methods for estimating the shaft capacity.