SLOPE SOIL STABILIZATION THROUGH BIOCEMENTATION BY NATIVE BACTERIA IN CHUGOKU REGION, JAPAN

Abstract

In this research, a study has been carried out to investigate the potential use of native bacteria from the Chugoku region of Japan for slope soil stabilization. In the biocementation process, soil improvement occurs due to the crystallization of calcium carbonate, which binds soil particles by the enzyme urease of ureolytic bacteria. The precipitated carbonate cements the particle contacts and fills the pores with or without bridging the adjacent soil particles, thereby eventually stiffening the soil matrix. A 60 x 20 mm mold has been used with the natural slope soil collected from Ube City, Yamaguchi, Japan. The treatment was carried out for 21days at the constant room temperature. A direct shear test has been carried out to examine the strength of the bio-cemented soil under the normal stress of 50, 100 and 150 kPa. It was observed that the angle of friction has increased after the biocementation of soil (28 to 34 degrees). Test results indicated the effectiveness of the native bacteria for increasing the strength of the slope soil. The generated calcium carbonate revealed that the native bacteria of Chugoku region could use biocementation for potential slope stabilization.