MICROBIOLOGY IN GROUND IMPROVEMENT

Abstract

Different techniques are used for improving the properties of soil (reducing the permeability and strengthening the soil) such as deep dynamic compaction, Vibro-flotation and Vibro-compaction, chemical grouting, soil nailing and piling etc. Along with advantages of all the above listed techniques there are disadvantages too such as high cost, high energy consumption and there adverse effects on environment restrict their applications. Microbial Geo-technology have three major applications including Bio-clogging, Biocementation and Biogas. Bio-clogging refers to a process in which pore-filling materials are produced through microbial activities so that the porosity and hydraulic conductivity of soil can be reduced. Bio-cementation refers to a process in which particle-binding materials are generated through microbial activities so that the shear strength of soil can be increased. Biogas refers to generation of gas (N2) to increase the liquefaction resistance of soil. We can also use bio-grouts to reduce the migration of heavy metals and organic pollutants, control ground water flow, and prevent piping of earth dams and dikes. Bio-cementation is used to prevent soil avalanching, reduce the swelling potential of clayey soil, to mitigate the liquefaction potential of sand, to enhance stability of slopes and dams, and compact soil on reclaimed land sites. Our research is based on using bio-grouts to improve engineering properties of soil which is based on microbial induced calcite precipitation, we are majorly focused on biocementation.