The effect of new curing agent on the erosion resistance of reclaimed soil in open pit slope of desert mining area in Xinjiang

The northern foothills of the Tianshan Mountains in Xinjiang are rich in mineral resources. However, the ecological environment is relatively fragile and has a poor self-recovery capacity. Characterized by frequent wind-blown sand and short-duration heavy rainfall, the climate has led to severe soil erosion. As a non-traditional chemical soil stabilization material, polymers among various types of soil stabilizers are receiving increasing attention due to their environmental friendliness, effectiveness, and low dosage requirements. Therefore, the erosion resistance of reclaimed soil was enhanced using polyacrylamide and nano - SiO₂ as additives. A physical slope model test was conducted under different freeze–thaw and dry–wet cycle counts (0, 1, 3, 6, 9, 12, and 15 cycles) to evaluate the erosion resistance of reclaimed soil mixed with various ratios of polyacrylamide and nano - SiO₂ (2∶1, 1∶1, 0∶1, 1∶0, 1∶2, and 0∶0). The improvement mechanism was investigated using scanning electron microscopy (SEM), accompanied by a vegetation comparison experiment. The results showed that: (1) Three-dimensional laser scanning of the slope model surface indicated that with the fewest abnormal color and morphological variations, the surface of the 3D color scale map appeared smoother when the ratio of polyacrylamide to nano - SiO₂ was 1∶1. In contrast, the color scale maps of other mixing ratios showed more varied colors and surface morphologies, indicating that the 1∶1 ratio resulted in the fewest cracks on the slope model. New color regions appeared in the color scale maps as the number of cycles increased. This indicates that more pores and cracks developed within the interior of the slope. During scanning, these regions may exhibit different colors , thereby increasing the color diversity of the scale map. (2) The mechanism by which polyacrylamide improves reclaimed soil primarily involves adsorption, flocculation, and water retention. The improvement mechanism of nano - SiO₂ mainly involves the filling effect and surface energy effect. In the plant growth experiment, the plants in the untreated soil showed signs of withering by day 28, while those in the improved soil continued to grow vigorously. This indicates that the addition of polyacrylamide and nano - SiO₂ not only improved the germination rate but also extended the lifespan of the plants. The combination of polyacrylamide and nano - SiO₂ at a 1∶1 ratio, based on the above experimental results, showed the best improvement effect on the erosion resistance of reclaimed soil in the northern foothills of the Tianshan Mountains. A new approach for ecological restoration of mines in the northern foothills of the Tianshan Mountains is provided by adding environmentally friendly novel stabilizers. In addition, it is low in cost and holds great potential for practical application.