Geotechnical Engineering Soil Mechanics

Effect of biological activity on soil mechanical 

The understanding of soil behavior during the last 300 years has centered on mechanical principles, geological processes, and later on, mineralogy and the relevance of colloidal chemistry. More recently, research in biology and earth science has enabled important advances in understanding the crucial involvement of microorganisms in the evolution of the earth, their ubiquitous presence in near surface soils and rocks, and their participation in mediating and facilitating most geochemical reactions. Yet, the effect of biological activity on soil mechanical behavior remains largely underexplored in the geotechnical field. It is shown that microorganisms play an important part on the formation of many fine grained soils, can alter the behavior of coarse grained soils (including hydraulic conductivity, diffusion and strength), accelerate geochemical reactions by orders of magnitude, promote both weathering and aging, and alter the chemical and mechanical properties of specimens after sampling. While extensive research is needed to delineate the full impact of biomass and biomediated reactions on soil behavior, it is anticipated that a proper understanding of biological principles will lead to improved soil characterization, enhanced understanding of soil behavior, and even alternative geotechnical engineering solutions.