Increasing the soil erosion resistance is one of the core issues in slope erosion control and ecological environmental restoration of open-pit coal mine (OPCM) dumps. In this study, fly ash (FA) and polyacrylamide (PAM) were used to improve the soil quality of an OPCM dump, and an indoor physical model was constructed to investigate the water and soil loss characteristics of the improved soil via simulated rainfall experiments. Scanning electron microscopy and Pore and Crack Analysis System software were employed to systematically investigate the erosion resistance mechanisms of the improved soil qualitatively and quantitatively. Finally, the improved technique for order preference by similarity to an ideal solution (TOPSIS) method was adopted to evaluate the reclamation potential of the improved soil. The results revealed that under the action of PAM (PAM and PAM–FA), the average erosion rate of the slope decreased by more than 90 %. Compared with that in the control group, when FA was applied alone, the slope erosion rate first decreased and then increased with increasing FA content. Upon PAM addition, the erosion pattern changed from the splash erosion stage, cave erosion stage, gully erosion stage, and tensile slip stage to the splash erosion stage and cave erosion stage. However, no obvious change in the runoff pattern. Erosion and runoff patterns are generally affected by the amendment type, addition concentration, porosity, pore shape, pore direction and hydrological environment. The erosion resistance mechanism of the improved soil entailed the formation of more stable soil aggregates via filling, cementation, skeleton support generation, and flocculation of FA and PAM. In addition, the optimal soil improvement was achieved when FA and PAM were added at levels of 16 % and 0.01 %, respectively. The obtained research results could be used for erosion control and ecological environmental protection of coarse-grained soil slopes in mining areas, highways and other fields and could be widely applied.

中文翻译：

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粉煤灰和聚丙烯酰胺改良露天煤矿排土降雨侵蚀机理及复垦潜力模型试验研究


提高土壤抗侵蚀能力是露天煤矿排土场边坡侵蚀治理和生态环境修复的核心问题之一。本研究采用粉煤灰 （FA） 和聚丙烯酰胺 （PAM） 改善 OPCM 垃圾场的土壤质量，并构建室内物理模型，通过模拟降雨实验研究改良土壤的水分和土壤流失特性。采用扫描电子显微镜和孔隙和裂纹分析系统软件对改良土的抗侵蚀机制进行了定性和定量研究。最后，采用改进的理想解相似顺序优先技术 （TOPSIS） 方法评价改良土壤的复垦潜力。结果表明，在 PAM （PAM 和 PAM-FA） 的作用下，边坡的平均侵蚀率降低了 90 % 以上。与对照组相比，单独施用 FA 时，随着 FA 含量的增加，斜坡侵蚀率先降低后增加。添加PAM后，侵蚀模式由飞溅侵蚀阶段、洞穴侵蚀阶段、沟壑侵蚀阶段和拉伸滑移阶段转变为飞溅侵蚀阶段和洞穴侵蚀阶段。然而，径流模式没有明显变化。侵蚀和径流模式通常受改良类型、添加浓度、孔隙度、孔隙形状、孔向和水文环境的影响。改良土壤的抗侵蚀机制需要通过填充、胶结、骨架支撑的产生以及 FA 和 PAM 的絮凝形成更稳定的土壤团聚体。 此外，当 FA 和 PAM 的添加量分别为 16 % 和 0.01 % 时，实现了最佳的土壤改良。所得研究成果可用于矿区、公路等领域粗粒土边坡的侵蚀控制和生态环境保护，具有广泛的应用价值。