Laboratory assessment of some geotechnical properties of a biopolymer treated sand

This thesis presents results of laboratory assessment of creating seepage barriers in a sandy soil and improving its geotechnical parameters using biopolymer additives, which consist of polysaccharides and water. Polysaccharides strongly interact with water to produce a viscous suspension. The research analyzes the potential use of biopolymer, namely xanthan gum to reduce hydraulic conductivity of coarse and medium sandy soils, and to strengthen their engineering parameters. For that reasons hydraulic conductivity, consolidation, triaxial, and unconfined compressive strength tests were carried out. Amount of the biopolymer used in a sample fall between 0.1 and 1.5%, by dry weight. Permeability tests were carried out on two different specimens, which were coarse sand (1.18 - 2.00 mm) and medium sand (0.075 - 1.00 mm), and other tests were conducted on medium quartz sand only. The results indicate that geotechnical parameters of the soil change significantly based on the amount of bio substance, gradation of the sand and curing time. It is concluded that biopolymers application could be used as a seepage barrier installation or general soil improvement technique, required to protect some geotechnical works including foundation, underground structures and waste disposals.