Characteristic Shear Strength Parameters Derived from Cone Penetration Test

The interpretation and application of CPT (cone penetration test) results is characterized by considerable variability of data, either in measured or correlated parameters.According to the requirements of Eurocode 7 the existing variability in so il properties has to be taken into account statistically during the determination of the characteristic values of each parameter.This should be done by selecting a cautious estimate of the value affecting the limit state.Obtaining the characteristic values o f CPT measurements is not an easy task and on this aspect nor clear neither unified guidelines exist.This paper focuses in several approaches to characterize the cone resistance and the sleeve friction using simple statistical analysis, in order for these parameters to be applicable in design.Similar procedures are then applied to determine the characteristic values of correlated parameters fro m CPT such as the effective friction angle for sands and the undrained shear strength for clays.The resulting characteristic v alues of the considered parameters emphasize the fact that the prediction and the interpretation of characteristic values of soil prop erties is a complicated and biased procedure.