Application of microbially induced calcium carbonate precipitation (MICP) in sand embankments for scouring/erosion control

Embankment is vulnerable to scouring and erosion during heavy rainfall events in most coastal areas in China. In this study, microbially induced calcium carbonate precipitation (MICP) technique was applied for sand embankments for scouring/erosion control. Three small-scale MICP treated sand embankments and one untreated embankment were first prepared using the injection method. Then, a series of laboratory scouring/erosion experiments were performed to investigate the slope failure process. The total erosion mass, the soil detachment rate and the content of MICP induced calcium carbonate (CaCO3) were also measured to evaluate the effectiveness of MICP treatment in sand embankments. Experimental results revealed that the average CaCO3 content was increased by 2% with each increment of MICP treatment cycle. The anti-scouring/erosion performance of MICP treated sand embankments was significantly improved as compared to the untreated one. Scanning electron microscopy (SEM) technique was also used to further study the micro-mechanism of the MICP treatment. The results revealed that the MICP induced CaCO3 was formed at the contact points among sand grains that increased the bonding strength, resulting in an improvement of scouring/erosion resistance of the treated embankment. This study preliminarily investigates the feasibility of using the MICP technique to mitigate scouring/erosion of sand embankment in coastal areas. More complicated environmental factors need to be considered for field implementation in the future.