Anti-erosion ability and water retention of spreading PAM powder granules and spraying PAM gum liquid on inner dump

Inner dumps formed by mining activities were prone to soil erosion. Slope improvement is an effective means to control soil erosion and ecological restoration. However, little research has been done on the effect of improver application methods on the effectiveness of amendments. This paper combined similar theory to build an indoor inner dump model, used simulated rainfall tests and microstructural analysis to investigate the erosion resistance and water retention of the inner dump under different methods of PAM. The results showed thattrace source erosion and side erosion didn’t occur in the inner dump model without PAM applied. Spreading PAM powder granules and spraying PAM gum liquid could reduce the internal earth pressure and pore water pressure of the inner dump to rainfall. Spraying PAM gum liquid could form a uniform film that can more effectively prevent rainfall infiltration. The carboxyl groups generated by the reaction of PAM and water could enhance the adhesion of clay minerals in the inner dump. The hydrogen bonds in the PAM gum liquid could connect water molecules, thereby forming interlocking soil particle aggregates, which enhance the anti-erosion ability of the inner dump. Spreading PAM powder granules and spraying PAM gum liquid can reduce the porosity of the improved soil, but spraying PAM gum liquid could reduce the porosity by 56.44%, which can effectively reduce water loss and had the best water retention. Therefore, spraying PAM gum liquid had better anti-erosion ability, which could lay the foundation for the ecological restoration of the inner dump.