Enhancing rainwater erosion resistance of black soil slopes in erosion gullies through microbially induced carbonate mineralization

Erosion gullies represent the most severe manifestation and prominent hazard of soil and water loss in the black soil regions of Northeast China, where slope management is crucial for controlling slope collapse and gully expansion. In response to the need for managing the slopes of large and medium-sized cut gullies in the black soil region, this paper proposes a new method of slope protection using Microbially Induced Calcium Carbonate Precipitation (MICP). Through a series of tests including penetration, calcium carbonate content, slaking, rainwater erosion, Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), and compatibility with slope protection plants, the effects of MICP treatment on the strength, water stability, rainwater erosion resistance, and growth of slope protection plants in black soil were evaluated. The results showed that under optimal conditions, MICP significantly increased the strength of black soil by 22.22 %. Additionally, MICP improved the water stability of black soil, reducing slaking mass by 11.36 %, and the mass loss caused by rainwater erosion by 88.55 %. By adjusting the concentration of the binding solution and considering soil depth, compatibility with slope protection plants can be achieved, with 0.5 mol/L binding solution treatment having minimal impact on the growth of ryegrass, a slope protection plant. SEM and XRD confirmed that MICP effectively enhanced the rainwater erosion resistance of black soil by altering its microstructure and crystal forms. This study demonstrates the potential application of MICP technology in controlling the expansion of slopes in black soil erosion gullies, offering a novel approach to the management of such erosion gullies.