Comparison of liquid limit of highly plastic clay by means of casagrande and fall cone apparatus

Gitte Lyng Grønbech, Benjaminn Nordahl Nielsen, Lars Bo Ibsen

In the proceedings of: GEO2011: 64th Canadian Geotechnical Conference, 14th Pan-American Conference on Soil Mechanics and Geotechnical Engineering, 5th Pan-American Conference on Teaching and Learning of Geotechnical Engineering

Session: Laboratory Testing

ABSTRACT: The connection between the Liquid Limit found using the Casagrande and the Fall Cone Apparatus is tested for the Danish Eocene Clay that has Liquid Limits up to 350% and Plasticity Index up to 300%, which is well outside the normal range of Casagrande™s Plasticity Chart. Based on the high plasticity of the Danish Eocene Clay two new classification categories are introduces to the Plasticity Chart in order to fully describe the clay; super high plasticity Clay (CS) and extremely high plasticity clay (CE), covering the range up to Liquid Limits up to 200% and 350% respectively. A correlation between the Liquid Limit from the Casagrande and the Fall Cone Apparatus is for super high plasticity clay. For extremely high plasticity clay it was found that the Fall Cone method underestimated the Liquid Limit with up to 43 percentage points, making the Fall Cone an unreliable method of finding the Liquid Limit for extremely high plasticity clay PRESENTACIONES TÉCNICAS La relación entre el limite liquido es obtenida usando los métodos de Casagrande y el Cono de caída, ensayados para arcillas Danesas del Eoceno las cuales alcanzan limites líquidos de hasta 350% e índices plásticos de hasta 300%, lo cual está muy alejado del rango contemplado en la gráfica de Casagrande. Basándose en la alta plasticidad de las arcillas Danesas del Eoceno, dos nuevas categorías de clasificación son introducidas en el diagrama de plasticidad, de manera que la arcilla queda completamente descrita; arcillas súper plásticas (CS) y arcillas extremadamente plásticas (CE), de tal modo, que el limite liquido superior de 200% y 350% respectivamente queda completamente cubierto. Una correlación entre el limite líquido por Casagrande y el cono de Caída es hallada para arcillas súper plásticas. Para arcillas extremadamente plásticas, se halló que el método del Cono de caída infravalora el limite liquido hasta con un 43 por ciento, lo cual hace del Cono de caída un método poco fiable para determinar el limite liquido de arcillas extremadamente plásticas.

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Cite this article:
Gitte Lyng Grønbech; Benjaminn Nordahl Nielsen; Lars Bo Ibsen (2011) Comparison of liquid limit of highly plastic clay by means of casagrande and fall cone apparatus in GEO2011. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GEO11Paper1100,author = Gitte Lyng Grønbech; Benjaminn Nordahl Nielsen; Lars Bo Ibsen ,title = Comparison of liquid limit of highly plastic clay by means of casagrande and fall cone apparatus,year = 2011}