Evaluation of Erodibility Characteristics and Strength Optimization of Bacillus Thuringiensis-Induced Calcite Precipitation for Lateritic Soil Erosion Control

To mitigate the potential consequences of erosion on civil infrastructure and prevent erosion-related damage, it is essential to determine the erodibility of soil materials. This study evaluated the potential of microbial-induced calcium carbonate precipitation (MICP) to improve the strength and erosion resistance of lateritic soil for surface erosion control. Key erodibility parameters, namely the erodibility coefficient ( ) and jet index ( ) were determined, while bacterial foraging (BFO), particle swarm (PSO), smell agent (SAO) optimisation algorithms were applied to identify optimal treatment conditions. Untreated soil exhibited low resistance to water erosion under British Standard Light (BSL) compaction. Bio-treatment improved performance, with peak values of Ji = 0.012 and = 0.3045 cm3/N-s at Bacillus Thuringiensis-Bt (24 × 10⁸ cells/ml) and cementation solution-Cs (0.75 M). Superior results were obtained under British Standard Heavy (BSH) compaction, yielding optimum values of Ji = 0.0003 and = 0.0034 cm³/N·s at Bt (2.4 × 10⁹ cells/ml) and Cs (0.75 M). Among the optimisation methods, PSO performed best, followed by SAO and BFO. The study recommends bio-treatment at Bt (2.4 × 10⁹ cells/ml) and Cs (0.75 M) using the mixing method with BSH compaction to effectively mitigate erosion. PSO is identified as the most efficient optimisation approach.