EVALUATION OF COMPACTION METHODS ON SOME COHESIVE SOILS USING REGRESSION MODELLING

ABSTRACT

Out of the different types of compaction methods, the standard compaction and modified compaction method have been two very common methods used in the laboratory to determine the compaction characteristics of soils. The aim of the study is to model the relationship between modified proctor compaction parameters and standard proctor compaction parameters of different cohesive soils collected from different sites in Ovia North East Local Government Area, of Benin City. Disturbed soil samples were collected by means of a hand auger from Oluku, Nitel, Ovbioghie and Iwu area in Ovia North East Local Government Area, at depths of 0.5 m, 1.0 m, 1.5 m and 2.0 m by means of hand auger. Preliminary tests were conducted to classify soil samples collected and then Standard Proctor Compaction Test and Modified proctor Compaction Tests were also conducted. The initial examination of soil properties indicated specific gravity values spanning from 2.42 to 2.73. The Atterberg limits revealed variations in plasticity, with liquid limits ranging from 30.00% to 46.00% and plastic limits from 9.85% to 21.55%. These soils, falling within the medium plasticity range, were classified as transitioning from organic clay to inorganic clay, containing fines exceeding 35%. Standard compaction tests displayed notable differences in maximum dry density (MDD) ranging from 1.538 g/cm³ to 1.713 g/cm³ and optimal moisture content (OMC) 11.20% to 17.45%. The regression model that connects the MDD from the standard proctor compaction test and the modified proctor compaction test when validated shows that the MAE was 0.01755. And the regression model for the OMC had a R2 of 0.6089, with an MAE of 0.3883 and the validation check showed that the R squared value was 0.59 and the RMSE was 0.3098.