Review on Study of Soil Stabilization by Application of Microorganisms

In recent years when there is a scarcity of desired land sites to satisfy the rapid development of infrastructures in metro cities, the engineers are facing great challenge of improving the properties of the soil which are going to carry the transferred load from the superstructure, ex: different types of buildings, bridges and roadways. The soil improvement techniques nowadays are emerging by the implementation of various significant ways to enhance the mechanical engineering properties of different soil types, like different types of expansive soils and minerally active soils. The soil treatment methods with chemical and cement grout are used increasingly by the engineers. The chemicals and cement used as a soil stabilizing material affect the natural environmental properties of the soil, hence, hindering the groundwater flow. To overcome their ill effect on soil and underground water, more sustainable method is the need of the time. Hence, engineers now are using the most readily available microorganisms and biochemical processes which are naturally active in subgrade soils to enhance the mechanical parameters of earth in survivable and cost-effective way. The main purpose of this kind of implementation is to improve both physical and engineering parameters of soil to use and reuse the soil when needed. The most important uses bio-clogging and bio-cementation are introduced. Bio-clogging is the process which produces the void clogging materials through biological activity which affects the pore spaces and permeability of soil. Bio-cementation, the process in which particle linking materials are generated because of the biological methods in situ for which the resisting capacity of the earth increases significantly. Bacteria which can grow in absence of oxygen and microaerophilic are the most eligible bacteria for the bioremediation of the soil.