DBPapers
DOI: 10.5593/SGEM2016/B11/S02.096

DETERMINATION OF LIQUID LIMIT OF HIGH PLASTICITY SOIL BASED ON THE CONE PENETRATION AND CASAGRANDE METHOD

E. Hrubesova, B. Lunackova, O. Brodzki
Wednesday 7 September 2016 by Libadmin2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-55-1 / ISSN 1314-2704, June 28 - July 6, 2016, Book1 Vol. 1, 761-768pp

ABSTRACT
This paper presents results of experimental works focused on the determination of liquid limit of bentonite and a mixture of bentonite with sand. Both liquid limit and plastic limit are the most important Atterberg´s limits, which are fundamental for the behaviour of cohesive soil. Generally, two basic methods for the evaluation of liquid limit are used – Casagrande method and cone penetrometer method. Standard cone penetrometer test (30 °/80 g cone) is based on assumption of uniform undrained shear strength 1.7 kPa at liquid limit for all types of soil. According Hansbo theory this assumption resulted to the penetration of 20 mm at liquid limit for widely used standard penetration test. However, for high plasticity soil this standard penetration approach gives significantly lower values of liquid limit in comparison with Casagrande cup test. Paper presents experimental values of the liquid limit of bentonite and its mixtures based on modificated Mohajerani methodology for the evaluation of cone penetration test (new calibration line for cone penetrometer liquid limit), comparison these results with the standard penetration test (cone penetration of 20 mm) and Casagrande (cup) method also.

Keywords: Consistency of cohesive soil, liquid limit determination, Casagrande (cup) method, cone penetrometer method, new calibration line for cone penetrometer test (Mohajerani)