Author : Naufila 1
Date of Publication :17th April 2019
Abstract: Earth embankment dams are one of the most commonly constructed hydraulic structures. Seepage induced internal erosion is one mode of failure in in earth filled embankment dams. In this study, the applicability of microbially induced carbonate precipitation (MICP) for internal erosion control is examined in laboratory using sand – gravel mixture of ratio 1:1. A series of internal erosion tests are conducted using a rigid wall downward erosion test apparatus for untreated, 0.2M, 0.4M, 0.6M, 0.8M and 1M specimens. The tests are also conducted for 3 days and 7 days cured specimens. The flow rate of water is varied as low, medium and high flow. Hydraulic conductivity, total mass eroded and erosion rate are characterized during the internal erosion process. It is found that MICP treatment facilitates the reduction of erosion and hydraulic conductivity in sand – gravel mixture investigated in the current study. The optimum carbonate precipitation is seen in 0.6 M specimen and 7 days cured specimens. Carbonate precipitation increases the erosion resistance by absorbing and bridging the contacts of fine and coarse particles.
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