| Tailings is a special kind of industrial buildings and also essential industrial construction for mining enterprises, while it is an artificial debris flow hazard with high potential energy as a matter of fact. There is no effective method of consolidation at present. The microbial induced calcium carbonate deposition technology has the advantages of friendly environment and low energy consumption. It has become a hot research topic in the field of geotechnical engineering.In this paper, the research object is based on the The 1# mud-tailings reservoir of China aluminum co. LTD., Guangxi, and the results are as follows:By selective enrichment culture and plate separation method,1 strains of urea decomposing bacteria were isolated from soil. The growth characteristics were studied, and the optimum conditions were as follows:the initial pH 7, and the temperature was 35°～40°.By determining the activity of the enzyme, the enzyme activity of the strain was the highest in the logarithmic phase, and the trace elements of Ni can improve the activity of the enzyme, but the high will inhibit the growth of the strain.Calcium source species and concentrations of bacteria induced calcium carbonate deposition. With calcium chloride and calcium nitrate as nitrogen source respectively, calcium chloride precipitation fixed rate can reach 45%,but calcium nitrate rain only can reach 30%. And the best calcium chloride concentration is 0.5mol/L.The strains can reduce the permeability coefficient and the compression coefficient, increase the cohesion of soil and reduce the internal friction angle by the laboratory test, the consolidation compression and the three axis shear test. The consolidation of soil has a certain promotion. |
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