Use of biological manner to produce Calcite cement is a new manner for soil improvement in geotechnical engineering. Cement was produced among the soil with non-pathogenic microorganisms that are found naturally in soil, can bind the soil grain together. These manners are very ecological because we use naturally microorganisms. In this thesis we use a bacterium called Sporosarcina Pasteurii (PTCC 1645) for soil improvement. Scientists showed that we could produce Calcite cement but in operationally scale we try to introduce material that can to keep other materials between its layer structure, and release them in a time interval slowly. For this purpose we used bentonit. For measurement of penetration depth improvement depth with improver slurry (bio groute + bentonit) we used a PVC mold (with 1 meter height 110 millimeter diameter) full of sand. Soil samples was compacted i this cylindrically mold to achieved a density of 1.65 gr/cm3 and the grouting procedure was initialized. After prepare this mold we splashed improver slurry to 3 time. We saw the sand column was improved in 10 cm to 30 cm. and bio logical slurry penetrated to 50 cm. We used a test called canonical penetration that was performed in wet dry condition. Also we used a ferrous cone (weight 250 gr) for a qualitative study of surface resistance. This test showed that cone penetration was reduced even to zero. In a permeability test between tow samples that first sample was improved with bio grout and second sample was improved with bio grout+bentonit (improver slurry), we saw that bentonit didn’t have any role to bind the soil grain together, because if the bentonit had a role in this improvement, we could see a large differences between values of permeability coefficients while the permeability test results didn’t show any difference.
