Estimation of dynamic soil properties for geotechnical analysis in the Niger Delta using index testing and empirical correlations

Abstract This study investigated geotechnical properties of subsurface soils from Mbiama town in Rivers State, Niger Delta region through laboratory index testing and development of empirical correlations to estimate dynamic soil parameters. Grain size analyses revealed heterogeneous stratigraphy transitioning from upper clayey sands to lower gravelly sands deposited under changing fluvio-deltaic conditions. Atterberg limits exhibited decreasing plasticity trends with depth confirming the textural variations. Laboratory data conforms to layering architecture inferred from depositional facies analyses. Predictive models were developed relating Standard Penetration Test blow counts (SPT-N) and shear wave velocity (Vs) to depth, moisture content and percentage sand. High regression coefficients validated models' accuracy in reproducing over 90% of field measurements. Factor of safety against liquefaction was correlated to SPT-N, accounting for density-dependent properties. Index-based characterizations aligned well with trends predicted by the empirical correlations. This research demonstrated robust indirect estimation of dynamic geotechnical indices for foundation design and seismic risk analysis in data-scarce Niger Delta through standardized field and laboratory index testing integrated with depositionally-linked predictive models.