Application of EICP for coastal erosion mitigation

An experiment to evaluate the use enzyme induced carbonate precipitation (EICP) for coastal erosion mitigation was conducted in the large wave flume at the O.H. Hinsdale Wave Research Laboratory at Oregon State University. The surface of a model sand dune was stabilized using EICP. The test slope was 7.2 m long, 1.8 m wide, and 1.5 m high (measured from the mean water level) and was composed of a local uniform fine beach sand. The slope surface was treated via EICP to form an approximately 5 cm-thick crust. In addition to crust formation, a 0.38 m-deep, 0.8 m in breadth zone at the toe of the slope was treated in lifts using EICP to form a toe wall across the 1.8 m width of the flume. The erosion resistance of the treated slope was tested by applying 20 wave trains of progressively increasing intensity. The crust remained intact for the first two wave trains and then progressively eroded until, at the end of the trials, the crust was completely eroded. However, portions of the toe wall remained intact at the end of the experiment and appear to have inhibited undercutting of the slope. The results of the experiment suggest that coastal erosion can be mitigated by construction of an EICP-stabilized toe wall to protect against undercutting of a slope and that it may be possible to construct a surficial EICP barrier of sufficient thickness to reduce slope erosion to a minimum, depending on the magnitude of the wave load.