Applying biomineralization technology to study the effects of rainfall induced soil erosion

The rainless days and drought seasons reveal a tendency to lengthen the wet and dry period in recent years in Taiwan. In the bare riverbeds in central Taiwan, such as the Dajia and Zhuoshui rivers, fugitive dust is the common problem during the winter's dry period with northeast monsoon. The study aims to use the biological method, Microbial-induced carbonate precipitation (MICP), to solidify the soil and implement a series of rainfall simulator experiments to reduce the Aeolian dust emission problems. Accordingly, the relationship between rainfall-induced soil erosion and its soil specimens are also discussed. The soil conducted the MICP for seven days as the curing age, and then be analyzed the degree of soil solidification under different conditions, rainfall intensity of 41 mm/h and 61 mm/h by the soil erosion experiment. The effect of soil solidification with various relative density of soils of 60%, 70%, and 80%, and hillside slopes of 5°, 10°, 20° were tested. The result indicated that, the higher the relative density of soils, the better the effect of soil solidification would be. The relative density of soils from 60% to 80% all kept the effect of soil solidification as applying to MICP. Therefore, it was important to select the curing age with the matching relative density of soils. Moreover, the most appropriate condition for the effects of soil solidification by MICP was the slopes below 10° and the curing age for seven days. The effect of soil solidification was still preserved in that with the high intensity rainfall (66 mm/h) due to the Aeolian dust emission commonly happening in the bare riverbeds with mild slopes.