Erosion Reduction of Coastal Sands Using Microbial Induced Calcite Precipitation

Abstract

Effects of sea level rising and increasing storm severity create a more damage prone environment for coastal regions. Large storm surges can be devastating to coastal infrastructure, damaging roads, utilities, structures, and endangering the lives of local residents. Coastal sand dunes act as a primary defense to wave action, making their resiliency of the utmost importance. Microbial induced calcite precipitation (MICP) offers a potentially sustainable alternative to seawall and revetment type solutions which destroy entire ecosystems in order to protect cities or other areas of interest. Bio-cementation has been shown to improve the strength and stiffness of unsaturated sand. The study presented herein displays the behavior of MICP treated coastal sand when subjected to wave action. Two wave tank tests were conducted to assess the change in measured erosion for untreated sand and moderately cemented sand. To quantitatively measure the reduction in erosion, 3-D morphology was observed using a laser scanner before and after subjecting the sand to wave action. Acoustic wave gauges were used to monitor the input wave functions and the breaking waves on the soil surface. Further understanding of the erosion reduction potential of MICP treated sand increases the feasibility of in-situ application to coastal sand dunes.