A comparison of different methods to determine the Atterberg´s limits in the laboratory

Ajla Šoše

Diplomová práce

Abstract:

As the water content in the soil increases, the consistency of fine-grained soil changes from solid to plastic state, and eventually to a liquid form. Plastic limit (PL) is the point at which the consistency of the soil is changed from solid to plastic state. Liquid limit (LL) is the point at which the consistency is transformed from plastic to liquid state. These two limits are collectively referred to as Atterberg (consistency) limits, which are of crucial importance for soil classification and engineering purposes. The aim of this thesis was to examine and compare different methods to determine Atterberg limits in laboratory. Plastic limit has been determined by rolling thread method, while two basic methods were used for the evaluation of the liquid limits – Casagrande apparatus and cone penetrometer. Disturbed soil samples have been taken from three different localities in Prague: Ruzyně, Suchdol and Uhříněves. All soil samples had the same soil texture – silt loam. For plastic limit test determination, 30 samples have been used; 10 samples for each locality. Twenty-four samples have been obtained per each locality and per each method of liquid limit tests. In total, there have been 144 samples; 72 samples for the Casagrande apparatus and 72 samples for the cone penetrometer. Average LL values ranged between 31 and 40.2% for Casagrande apparatus, while values were a bit higher for cone penetrometer, varying between 32.2 and 43%. Presented results of laboratory tests show that there was no significant difference in results between Casagrande cup and cone penetrometer. Nonetheless, Casagrande apparatus showed slightly more reliable results, compared to the cone penetrometer, as the first method had lower standard deviation and coefficient of variation values. Precisely, coefficient of variation for Casagrande apparatus varied from 0.4 to 2%, while CV values for cone penetrometer were slightly higher – ranging between 0.5 and 2.3%. Obtained results indicate the need for further research in this area, focusing on acquiring more samples with different soil textures and clay content, preferably from different localities in the Czech Republic.

Keywords

Atterberg limit, plasticity limit, liquid limit, cone penetrometer, Casagrande apparatus

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 30. 7. 2020

Obhajoba závěrečné práce

• Vedoucí: prof. Ing. Svatopluk Matula, CSc.

Česká zemědělská univerzita v Praze

Fakulta agrobiologie, potravinových a přírodních zdrojů

Magisterský studijní program / obor:
Natural Resources and Environment / Natural Resources and Environment