Abdolreza Karimi - Assistant Professor, Civil Engineering Department, Qom University of Technology, Qom, Iran
Behrouz Ahmadpour - Master Student of Civil (Geotechnical) Engineering, Qom University of Technology, Qom, Iran
Mostafa Tavakoli - Master Student of Civil (Geotechnical) Engineering, Qom University of Technology, Qom, Iran

Today ground improvement may be required in many civil engineering projects. Some of usual methods of ground improvement may be have harmful effects on environment directly or indirectly. For example high amount of CO2 are released during portland cement or other man-made materials production. In recent years use of biological methods in geotechnical engineering have developed rapidly to improve the engineering properties of soil involve physical (density, gradation, porosity and saturation), mechanical (stiffness, compressibility and etc.) and conduction (hydraulic, electrical, thermal) properties. In these methods are used of microorganisms or enzyme for ground improvement purposes. In this paper some of biological methods are introduced and their mechanism and applications are expressed. Finally, advantages and limitations of biological methods are discussed.

Ground improvement, Biological method, Biogrout, Biocementation