Multivariate Assessment of California Bearing Ratio with Contrasted Geotechnical Properties of Soils in Ilorin-Lokoja Highway

California Bearing Ratio (CBR) is an important parameter used in designing pavement layers in road construction but testing this parameter requires time, labor, and huge cost. The study therefore applies multivariate approach to evaluate CBR based on contrasted geotechnical parameters along Ilorin-Lokoja highway. The results obtained showed that the migmatite-gneiss-derived soils are slightly more fines (< 0.075 mm; 7.4–59.6%), more plastic (PI; 1.6–39%), and have low strength (MDD = 1.8 mg/m3; CBR = 29.0%) than the metasediments (11–57.7%, 2.0–30%, 1.6 mg/m3, 23.6%) and older granite soils (8.2–32.7%, 2.6–13.4%, 1.7 mg/m3, 27.8%), respectively. The principal component analysis (PCA) revealed three major components (eigenvalues >1) which accounted for 83.8% of the total variance at the rate of 33.4, 14.7, and 11.4%. Major contributing variables for the components were fines (R = 0.87), plasticity index (R = 0.7), and coarse sand (R = 0.67%). Spatial distribution of these groups established interplay of sediment-gradation and moisture-connection evident in hierarchical cluster analysis that revealed patterns of homogeneity and soil relationships. Regression analysis established five models from predictor variables such as fines, activity, free swell, liquid and plastic limits, weighted plasticity index, optimum moisture content, and maximum dry density with the coefficient of determination (R2 = 0.33) and root mean square error (RMSE) of 7.80.

Swelling Clay Parameters Investigation Using Design of Experiments (A Case Study)

The present paper aims to investigate geotechnical parametric effects on the expansion behavior of clayey soils in Tebessa province northeast of Algeria using the Design Of Experiments (DOE) methodology. It has been used as powerful tools based on physical and mechanical properties, data results obtained within laboratory soil mechanics testing. This statistical tool methodology presents the factor screening design to determine the effect of different parameters such as dry unit weight, saturation degree, water content, plasticity index, etc., on the swelling pressure parameter which can be used as expansion behavior of clay indicator. All data previously collected in the studied prone area allows the ability of detailed analysis using design of experiment and parametric optimization process with response surface methodology (RSM). Each variable that present effects on swelling pressure is also discussed. Besides, the obtained models and equations related the factors affecting the expansion process have been determined. At the output process; the response desirability of the screening design methodology can be optimized by maximization or minimization of the optimal values affecting the swelling behavior. This process allows us to find the best describing models, whereas output results may be compared to empirical laboratory tests results to assess the RSM models.

Construction Materials and Dam Foundation While Memve’ele Dam Building in the Craton’s Region of South Cameroon

This chapter mainly focuses on engineering geology for dam construction from the Memve’ele region in Cameroon. Here, it deals with geotechnical and geological proprieties of both construction and dam foundation materials. This study is done at the aim to ensure that these materials need to be improved and how they have been used during dam construction. Field investigations, borehole information, density and seismic velocity measurements have been used, and results indicate that soil deposits have slightly clay content, mechanically well for dam construction and display a weak thickness layer particularly on the dam site. These conditions suggest that soil materials can be used as construction (cushion, transition layers, etc.) and foundation materials after few amendments. Ntem Formations appear weathered and fractured sometimes, though their mechanical behaviors display a good character for civil applications. However, engineering processes have been used to improve it by GIN (Grouting Intensity Number) methods. These formations have been used as construction (rip rap crushing aggregate, etc.) and dam foundation materials. Thus, this chapter contributes to highlight materials and dam foundation conditions which are crucial criteria encountered in the dam with emphasis on both theoretical study and practical application during dam construction.