煤矸石保水性差是影响植物生长的主要障碍因子，为提高煤矸石基质的保水性，以SOCO–SAP(高分子聚合物常用作保水材料，以下简称SAP)质量分数、容重、煤矸石粒径级配3个方面研究重构煤矸石基质水分及披碱草生长特性，筛选出适宜于高寒矿区保水层重构的材料参数规格。结果表明：SAP的使用极显著地提高了煤矸石的饱和含水量、毛管含水量、田间持水量，在容重和级配相同的条件下，其含量与SAP的使用量呈正相关；SAP可降低煤矸石的入渗速率，使用量越高，抑制水分入渗能力越强，在同一质量分数下，不同级配煤矸石的湿润锋到达土柱底部所用时间从短到长依次为偏砂 < 偏壤 < 偏黏；SAP质量分数为0.1%与0.2%时，不同级配煤矸石各深度体积含水率提升较小，但使用量为0.3%和0.4%作用效果明显，且2者无明显差异，表明SAP适量使用时，对煤矸石的水分运移效果最佳；随SAP使用量的提高，不同级配煤矸石基质所表现出的披碱草生物量为(偏壤 > 偏砂 > 偏黏)，且在偏壤级配下，SAP使用量为0.3%时，生物量最大。因此，建议首选容重为1.3 g/cm³、偏壤级配(2∶2∶2∶2∶2)、SAP质量分数为0.3%，来作为高寒矿区保水层构建的主要基质配比，其次是容重为1.3 g/cm³、偏壤或偏砂级配、SAP使用量为0.3%或0.4%，这些配比基质保水性能较好，但植生性较前者较弱。该结果可为高寒无土矿区生态修复提供理论依据和技术支撑，同时为类似典型矿区土地复垦和固废资源化利用提供参考。

The poor water-holding capacity of coal gangue is the main obstacle factor affecting plant growth. In order to improve the water-holding capacity of coal gangue matrix, the water content of reconstructed coal gangue matrix and the growth characteristics of Elymus dahuricus are studied from three aspects: SOCO–SAP (Polymers are commonly used as water-retaining materials, hereinafter referred to as SAP) mass fraction, bulk density and particle size distribution of coal gangue, and the material parameters suitable for the reconstruction of water-holding layer in the alpine mining area are selected. The results show that: The use of SAP significantly increases the saturated water content, capillary water content and field water holding capacity of coal gangue. Under the same bulk density and gradation, the content is positively correlated with the use of SAP. The SAP can reduce the infiltration rate of coal gangue. The higher the amount of SAP used, the stronger the ability to inhibit water infiltration. At the same mass fraction, the wetting front of different graded coal gangue reaches the bottom of the soil column. The time from short to long is partial sand < partial soil < partial viscosity. When the mass fraction of SAP is 0.1% and 0.2%, the volumetric water content of coal gangue with different gradations at each depth increases slightly, but the effect of using 0.3% and 0.4% is obvious, And there is no significant difference between the two, indicating that when the SAP is used appropriately, the water migration effect of coal gangue is the best. With the increase of SAP dosage, the biomass of Elymus dahuricus in different graded coal gangue substrates is in the order of partial soil > partial sand > partial viscosity. Under a partial soil gradation, when the SAP dosage is 0.3%, the biomass is the largest. Therefore, it is suggested that the bulk density of 1.3 g/cm³, partial soil gradation (2∶2∶2∶2∶2), and the SAP mass fraction of 0.3% should be the main matrix ratio for the construction of water-retaining layer in the alpine mining area, followed by the bulk density of 1.3 g/cm³, partial soil or partial sand gradation, and the SAP usage of 0.3% or 0.4%. These ratios have a better water retention performance, but the plantability is weaker than the former. The results can provide a theoretical basis and technical support for the ecological restoration of alpine soilless mining areas, and provide a reference for land reclamation and solid waste resource utilization in similar typical mining areas.