Microbial-induced clogging is a method of leakage repair, a very important and promising application of biological technology in civil engineering. Metabolism and reproduction of microorganisms original in the soil become intensive after nutrients are supplied, and finally the hydraulic conductivity of the soil is decreased. 3 sand-column experiments by adding potato soup, glucose and water respectively on Beijing sand were performed in 2009. Like Nutrolase in Dutch Pleistocene soil and Japanese alluvial sand, potato soup can decrease the hydraulic conductivity of Beijing sand, but glucose can't. By ESEM and CT, the microstructures of the soil near the leakage are found to be different in columns added potato soup and water. The quantity of microorganisms and the loss of ignition of soil samples located in different position of sand columns are different. Contents of different Fe in soil samples of sand column supplied with potato soup have a significant increase. By XRD, the mineral compositions of soil samples near the leakage showed no significant difference with the initial sand sample. The results showed that the production of organics during the experiment was a main cause of microbial-induced clogging in Beijing sand column.
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