MICP-enhanced wind erosion resistance of desert sand: process parameter optimization and microstructural mechanism

This study employed the microbially induced calcium carbonate precipitation (MICP) technique to investigate the mechanism of desert sand stabilization through a multiscale approach, ranging from macro to micro levels. A multi-objective optimization model was created to enhance surface strength, CaCO₃ content, and solidified layer thickness using a comprehensive analysis of multiple factors. The solidification effect was validated with wind tunnel and water retention tests. Microstructural mechanisms were examined through XRD, SEM, and PCAS. Results indicate that the optimum parameters for MICP technology are the 1:2.12 mix ratio, the 1.895 mol/L cementation solution concentration, and 4 treatment cycles. There was also a clear correlation between the performance indexes after solidification. The parameters optimized by the response surface method were essentially the same as those obtained from the experiments, with a difference of less than 5 % between the repeated test results and the optimized results. Under conditions of high CSC (single treatment cycle) or low CSC (multiple treatment cycles), MICP-treated desert sands can achieve highly efficient sand fixation and long-lasting water retention. Microanalysis revealed that increasing CSC and T_c altered the mode of particle contact from point to surface, and a significant negative correlation was observed between pore parameters and surface strength. This proves that it improves the water retention and mechanical strength of desert sand.