Enhancement of soil ecological self-repair using a polymer composite material

The surface soil of newly cut slopes used in ecological protection engineering has a loose structure, low strength, and an inadequate water amount and moisture conservation capacity. This results in weak vegetation growth, negative long-term effects, and high maintenance costs. For this reason, a novel type of polymer composite, namely, an aqua-dispersing-nano-hinder (ADNB), optimised using different ratios of polymer adhesive and resin, was used to carry out water retention, erosion, and plant growth tests on weathered silty clay in the red beds of southern China. In addition, ADNB soil treatments were compared with untreated soil, and the occurrence and mechanism of water retention and erosion resistance in ADNB-modified soil were determined. The results show that with an increase in the amount of resin, the dry density of the soil decreased, and the void ratio, field capacity, and water holding capacity increased. With an increase in the amount of applied polymer adhesive, the dry density of the soil increased, and the void ratio, field capacity, and water holding capacity decreased, but were higher than those of the untreated soil. The mechanism of the ADNB modifying soil structure and improvements in its ecological self-repair were analysed. The adsorption and storage of free water by resin in the soil was observed through NMR imaging. Adding ADNB material at an appropriate proportion to the soil not only enhances the soil strength and erosion resistance, but also increases the soil water holding capacity and promotes plant growth. Thus, the ecological self-repair of the soil and the ecological protection of the slope can be significantly improved.