A different approach for determining atterberg limits

Atterberg Limits are crucial not only for soil classification but also for influencing various geotechnical parameters directly or indirectly. While both Casagrande and Fall Cone devices measure Liquid Limit (LL) values they do not mechanically measure the same soil strength parameters. It is observed by many researchers, as LL increases, the Casagrande LL values tend to be higher than those obtained from the Fall Cone method. The Fall Cone LL results typically rely on the Plasticity Chart for soil classification, which is primarily developed based on Casagrande test results. his study addresses these issues by exploring alternative methods and solutions. The Haigh and Mohajerani calibration methods were examined using 26 different test results, and a calibration method was formulated considering Hard-Base Casagrande devices. Additionally, a recently developed classification diagram that allows soil classification using Fall Cone LL results without needing plastic limit values was examined. Results showed strong consistency between calibrated Fall Cone and Casagrande values for wide LL spectrum, with the developed method KÇ yielding the highest correlation as 0.9961. In this study, the proposed calibration method was referenced from the Mohajerani method and its applicability has been proven. It has been concluded that the method should be keep calibrated in future studies using high liquid limit values. Soil classification was minimally affected, with only one type changing classification. The new diagram reclassified 13 soil samples, demonstrating enhanced precision and recommending its adoption in future studies.