Full-factorial Two-level Design in Optimizing the Contents of Olivine and Coir Fiber for Improving the Strength Property of a Soft Marine Clay

Abstract

ABSTRACT A 3-factor, 2-level full factorial design was employed in the current study to design the experiment, evaluate the results, and optimize the contents of olivine and coir fiber for improving the strength property of a soft marine clay. The influence of the independent variables (olivine content, coir fiber content, and curing time) on the response [unconfined compressive strength (UCS)] were investigated by analysis of variance (ANOVA). The ANOVA results show that olivine content and curing time significantly affected the UCS. A regression model was developed to relate the response to the variables. The developed model shows a good agreement between the predicted and actual values, demonstrating the validity of the regression analysis in the process optimization. The optimum conditions were found to be 30% olivine content, 2.5% coir fiber content, and 35 days of curing, which improved the UCS by approximately two-fold. The results demonstrate that both chemical modification and mechanical reinforcement by adding olivine and coir fiber are efficient techniques to improve the strength property of soft marine clays. The findings of the study also open up a promising perspective for using full factorial design in defining the optimal factor combinations for improving the strength properties of weak soils.