The effect of microbes on the stability of an unsaturated tropical slope

Abstract

Conventional geotechnical practice considers that soil is an inert construction material and its engineering properties do not change with time. However, soil is a living ecosystem, and its engineering properties naturally change as a stable ecological system is gradually established following initial construction. Over the last few decades, researchers started exploring a way to engineer some microorganisms’ activities in order to solve problems in geotechnical engineering. This paper assesses the effect of a biostimulated Microbial Induced Calcite Precipitation (MICP) on the stability of an unsaturated tropical slope. For that, data from an experimental characterisation study carried out for a tropical soil was used. For the assessment of the stability of the slope, a critical rainfall for the region was considered and the pore water pressure distribution was obtained. The stability of the slope was assessed using a ‘simplified’ shear strength criterion formulated in terms of unsaturated cohesion. Results show that the MICP treatment contributes to the stability of the slope. This positive contribution is more significant than the contribution of suction towards the stability of the slope.