Effect of Bio-Cementation Level and Rainfall Intensity on Surface Erosion Resistance of Biotreated Slope Using PEICP Method

Biomineralization technology is a promising method for soil cementation, enhancing its mechanical properties. However, its application in mitigating slope surface erosion caused by rainfall has not been fully explored. This study experimentally examined the feasibility of using plant-based enzyme-induced carbonate precipitation (PEICP) to reduce slope surface rainfall erosion through simulated rainfall tests. The effects of biotreatment cycles (<i>N</i>) and rainfall intensity (<i>R</i>_i) on erosion resistance were evaluated. The results demonstrated that increasing the biotreatment cycles improved the bio-cementation level, as evidenced by enhanced surface strength, increased calcium carbonate content (<i>CCC</i>) and thicker crust layers. Specifically, as the biotreatment cycles (<i>N</i>) increased from 2 to 6, the crust layer thickness expanded from 5.2 mm to 15.7 mm, with surface strength rising from 38.3 kPa to 244.3 kPa. Likewise, the <i>CCC</i> increased significantly from 1.09% to 5.32%, further reinforcing the soil structure and enhancing erosion resistance. Slopes treated with six biotreatment cycles exhibited optimal erosion resistance across rainfall intensities ranging from 45 to 100 mm/h. Compared to untreated slopes, biotreated slopes showed significant reductions in soil loss, with a decrease to below 10% at <i>N</i> = 4 and near-complete erosion resistance at <i>N</i> = 6. These findings highlight the potential of PEICP technology for improving slope stability under rainfall conditions.