Empirical modelling of geotechnical strength based on index properties: a case of patti formation, southern bida basin, nigeria

Abstract

The strength properties of geo-materials are paramount to the stability or otherwise of civil engineering structures. However, the determination of some of these properties such as California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) is costly and time-consuming. This necessitates the generation of models that can quickly predict the strength properties from cost-effective and less time-consuming index properties of the same geo-materials. In this study, an attempt has been made to predict the CBR and UCS values from Atterberg limit tests for sediments derived from Patti Formation, Southern Bida Basin, Nigeria. The tests were performed following appropriate codes of the British Standard Method for testing materials. Both linear and polynomial fitting models were employed for regression analysis between the index and strength parameters. The results showed that Liquid Limit (LL), Plastic Limit (PL), and Shrinkage Limit (SL) are strongly correlated with UCS and CBR, having R² ranging from 0.8-0.91. The equations can be used to quickly predict UCS and CBR in areas with similar geology. Similar studies are recommended in other parts of the country to aid the regional evolution of models for rapid strength characterization of geo-materials.