Load-Settlement Characteristics of Tropical Red Soils of Southern Nigeria

Abstract

This study investigated the relationship between the load-settlement curves obtained from field (in situ) plate load test under static loading conditions to those obtained from finite element (FE) analysis, for tropical red soils. Three test locations were selected within the University of Benin campus in Benin City, Nigeria. Laboratory tests were conducted on samples obtained from these three locations to obtain the index and strength properties of the soil, and these were used as input parameters for the FE analysis. The FE analysis was performed with PLAXIS 2D, using Mohr-Coulomb soil model as the constitutive model. Comparison of load-settlement curves obtained from the field plate load test with those obtained from the FE analysis showed that the FE tool was able to predict the ultimate vertical displacement for all three test locations, with good accuracy. The maximum vertical settlement obtained for Site A from the field plate load test was 8.79 mm, while that obtained from FE analysis was 9.02 mm. For Sites B and C, it was 12.77 mm vs 12.30 mm and 22.85 mm vs 22.30 mm respectively. Parametric studies were also conducted in order to evaluate the effect of variations in soil conditions on the static response of the soils. Results from the water table parametric analysis showed significant increase in vertical displacement as the soil immediately below the footing gets saturated. The results also showed that c and ? have significant influence on the load-settlement curves under static loading.