Experimental study on solidification of silt through urease-producing strains induced by ultraviolet mutagenesis

To improve the solidification effects of the microbially induced calcium carbonate precipitation (MICP) technology, the urease-producing strains are optimized by the ultraviolet (UV) mutagenesis. Subsequently, the modified bacterial strains are used to solidify silt by premixing bacterial with soil first and then injecting cementation solution (urea and calcium chloride) into soil. The unconfined compressive strength tests, calcium carbonate content determination and microscopic test analysis are conducted to comparatively study the curing effects of the strains before and after the UV mutagenesis. The results show that the UV mutagenesis technology can effectively improve the performance of the urease-producing bacterial strains, and increase the urease activity and the content of calcium carbonate produced by mineralization. The use of UV-induced bacterial strains to solidify silt can significantly improve the unconfined compressive strength of the soil. This study selects the excellent bacterial strains from the source and effectively improves the curing effects of the MICP technology.