Parameters Effects Evaluation of Microbial Strengthening of Sandy Soils in Mixing Experiments Using Taguchi Methodology

Abstract

The effects of experimental parameters including soil type, curing duration, inoculum size, and biomass and nutrients concentration on soil strengthening due to calcite precipitation by Sporosarcina pasteurii PTCC 1645 were investigated. The laboratory-scale mixing experiments on remolded samples were designed by the Taguchi method. Soil type proved to be the most incorporating factor, followed by curing time and nutrient concentration. The main effect and the interactions of the parameters were presented and the optimal conditions were obtained. This suggests the importance of local conditions including soil type on any future large-scale, in situ application.

Keywords:

• microbially induced carbonate precipitation
• mixing test
• operational parameters effect
• optimization
• soil strengthening
• Taguchi method
• unconfined compressive strength (UCS)

Acknowledgments

The project was part of ongoing research in the Isfahan Higher Education and Research Institute, IHEARI. We are grateful to Dr. Abtahi and Dr. Emtiazi for their kindly cooperation during the steps of this study. Also, we wish to thank Mr. Salmani who has helped us in the Laboratory of Soil Mechanics of IHEARI forperforming the soil measurements.