Biocementation of sand dike against erosion due to overtopping

Prevention of river or coastal dikes from erosion failure has become more important than ever due to the increasing impact of climate change. A microbially induced carbonate precipitation-based approach was investigated as a possible more sustainable solution for sandy dikes erosion due to overtopping. A series of model tests in a hydraulic flume were carried out on biotreated sand dike models. The models were treated using either surface spray or percolation method and then subjected to flow under various flow rates ranging from 2 to 22 L/s. The erosion, stability, geotechnical parameters, and the amount of calcium carbonate precipitated in the models were measured to assess the effect of the biotreatment. The testing results showed that the untreated sandy dike can be eroded easily, while no erosion occurred after the biocementation using five treatments of 1.5 M of cementation solution through either percolation or surface spray method. Data suggest that in almost the equivalent calcium carbonate content, the percolation method allows soil in a relatively deeper layer to be treated, while the changes occurred just on the formed crust of the models treated with the surface spray method.