Biocalcis and its Applications for the Consolidation of Sands

Abstract

The use of bio-mediated processes for geotechnical applications seems very promising for numerous underground geotechnical and environmental applications including waterproofing, soil stabilisation, pollution treatment, etc. As an alternative to existing consolidation methods, Soletanche Bachy has investigated a microbially induced carbonate precipitation process that showed to be potentially competitive for the treatment of fine-grained soils. Calcareous sandstone like material can be obtained within a few days, without significant modification of the permeability of the starting material. The process is implemented by percolating bacteria and calcifying solution throughout the mass to be treated. The paper presents some results of up-scaling works that have led to the validation of the industrial concept. The use of the process for mitigating liquefaction risks in seismic areas is discussed and design rules for real site application are detailed.