On the evaluation of pre-consolidation pressure of undisturbed saturated clays

The objective of this research was to show the effect of sample disturbance on the values of pre-consolidation pressure бc by using Schmertmann method. A prediction of бc form pocket penetrometer is also achieved. This was carried out by comparing the values of бc that were estimated from the results of consolidation tests, with the readings of pocket penetrometer for same samples. Pocket penetrometer is a simple tool that can be easily used in field and laboratory to initially predict unconfined compressive strength for clayey soils. Before carrying out the consolidation tests on undisturbed samples, pocket penetrometer readings were recorded. The correlation obtained between pocket reading and бc values that resulted from consolidation tests was found to be valid for a wide range of clay stiffness, ranging between medium stiff to very stiff clay. As for soft clay, this correlation was found not to be applicable where its behavior is believed to be greatly affected by the degree of disturbance occurring to samples during drilling.