Comparison of casagrande and cone penetration tests for the determination of the liquid limit of natural soils Doǧal zemi̇nleri̇n li̇ki̇t li̇mi̇ti̇ ni̇n beli̇rlenmesi̇nde casagrande ve koni̇ batma yöntemleri̇ni̇n karşilaştirilmasi


Journal of the Faculty of Engineering and Architecture of Gazi University, vol.21, no.4, pp.711-720, 2006 (SCI-Expanded) identifier


The measurement mechanism of Casagrande and cone penetrometer methods which are used for the determination of liquid limit that is a measure of undrained shear strength of soils are different from each other. In the Casagrande method the viscous shear resistance is effective. However in cone penetrometer method the frictional shear resistance is effective. For this reason, the liquid limit values obtained with these methods are different from each other. Generally cone penetration method yields higher liquid limit values in soils where liquid limit is lower than 100 % (kaolinitik soils), whereas Casagrande method gives higher liquid limit values soils where liquid limit is higher than 100 % (montmorillonitic soils). In this study, the liquid limit values of 13 natural soils that were taken from Ankara and different regions of Turkey whose liquid limit values are lower than 100 % were compared. According to the results of test, it was determined that the cone penetration test yields higher liquid limit values than the Casagrande method in the range of 0.2 % and 22 %. As a result, in this study the mechanisms that cause different liquid limit values in cone penetration and Casagrande tests where discussed and the importance of these differences geotechnical applications was expressed. In addition, linear regression analyses were performed for the determination of the relationship between these methods. According to regression analysis, correlation coefficient 0.983 (13 data) and 0.961 (86 data) were obtained which display strong relationship between two methods.