Impact of Biologic Single and Mixed Medium on Mechanical-Hydraulic properties of Dune Sand

Today, new improvement methods to improve the geotechnical properties of soils are considered. Although a lot of improvement techniques are in use around the world, they have their own advantages and disadvantages. Chemical, physical, mechanical, biological and electrical techniques may be named as the common methods of soil improvement (Karol, 2003). Some of the methods, particularly those using cement and other toxic chemical grout, may cause environmental problems which limit their usage. In this regard biological improvement is an innovative method that uses microorganisms in the soil and biochemical reaction networks, the soil physical and mechanical properties are improved. In this research, mixed culture performance was studied against single culture of bacteria on physical strength properties of sandy soil, as the stabilization efficiency was evaluated in terms of the soil compressive strength, secant stiffness, and permeability with unconfined compression and falling head tests, respectively.