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Документ Formation of water-impermeable crust on sand surface using biocement(2011) Stabnikov, Victor; Naemi, Maryam; Ivanov, Volodymyr M.; Chu, JianThis paper examines the feasibility of using calcium-based biocement to form an impermeable crust on top of a sand layer. The biocement used was a mixture of calcium salt, urea, and bacterial suspension, which hydrolyzed urea with production of carbonate and an increase of the pH level. Applying 0.6 g of Ca per cm2 of sand surface, the permeability of the biocemented sand can be reduced from 10−4 m/s to 1.6•10−7 m/s (or 14 mm/day) due to formation of the crust on sand surface. The rupture modulus (maximum bending stress) of the crust was 35.9 MPa, which is comparable with that of limestone. The formation of a water-impermeable and high strength crust layer on sand surface could be useful for the construction of aquaculture ponds in sand, stabilization of the sand dunes, dust fixation in the desert areas, and sealing of the channels and reservoirs in sandy soil.Документ Microbial method for construction of aquaculture pond in sand(2013) Chu, Jian; Ivanov, Volodymyr M.; Stabnikov, Victor; Li, BingA method to construct an aquaculture pond in sand using microbial biocementation is presented in this paper. The microbially induced calcium carbonate precipitation process was used to form a low-permeability layer in sand for the construction of a water pond model in the laboratory. The test results indicated that the permeability of sand was reduced from the order of 10−4 m/s to 10−7 m/s when an average 2.1 kg of calcium (Ca) per m2 of sand surface was precipitated. The bending strengths of the walls and the base of the model pond were in the range of 90–256 kPa. The unconfined compressive strengths for the samples taken from the walls and the base of the pond were in the range of 215–932 kPa.