Erosion of Biotreated Field-Scale Slopes under Rainfalls

Rainfall erosion in slopes is a common natural disaster threatening the safety of urban infrastructure and farmland and the full life cycle sustainability of construction. In this study, a large-scale field test was performed to investigate the effect of microbially induced calcite precipitation (MICP) on the mitigation of rainfall erosion. Slopes treated with 0, 3, 6, or 12 cycles of MICP were subjected to an artificial heavy rainfall test with an intensity of 175 mm/h. The test results showed that MICP could change the erosion pattern of the slopes significantly. The response time to rainfall and velocity of the wetting front could be increased and decreased with the increase of biotreatment level. The penetration resistance of the slopes could be enhanced with biotreatment level, corresponding to the increment of calcium carbonate (CaCO3) content. The scanning electron microscopy (SEM) images showed that CaCO3 could fill pores and bond soil grains effectively with the increase of the biotreatment level, leading to a decrease in the rain infiltration rate and an increase in soil strength. It is proposed that MICP is a highly potential method for mitigating rainfall erosion for slopes, whose technique should be further studied to improve the mitigation efficiency.