Anhui Province Engineering Laboratory for Mine Ecological Remediation, Anhui University
Institute of Energy, Hefei Comprehensive National Science Center
State Key Laboratory of Deep Coal Mining and Environmental Protection

煤矸石是煤矿沉陷区土地充填复垦的关键材料。但煤矸石质地较为粗糙，持水性较差，煤矸石重构土壤的孔隙结构和水盐运移都会与原状土壤产生一定差异。为研究煤矸石充填土壤孔隙结构变化以及对水盐运移的影响，利用CT扫描技术和图像分析方法，分析覆土、泥矸混合、矸石与原状土样品的孔隙结构差异，同时设计一种室内重构土壤水盐运移模拟装置，通过在实验装置不同深度布设传感器，连续记录重构土壤剖面水分与盐分的运移情况。结果表明，在原状土、覆土、泥矸混合与矸石4份样品中，矸石样品孔隙率高于其他样品，达到8.299%，导致其持水能力较差；泥矸混合样品小孔隙占比高，达到58.73%，孔隙连通性较差，缺乏水分运移通道，导致层间障碍带的形成；覆土样品与原状土样品孔隙结构非常接近。在土柱模拟实验中，土壤盐分含量随水分运移而变化，各土壤层含盐量均先升高后降低，入渗结束后，表层土壤完成脱盐，深层土壤呈现积盐状态。在注水6 d内，土壤层含盐量均先降低后升高，50 cm土壤层变化幅度最大，为38.34%。深层土壤盐分借助毛管力作用向上运移，表层土壤含盐量逐渐回升。由于层间障碍带的存在，矸石层水分与盐分均难以向上运移，其含量逐渐下降。研究结果可为沉陷区土地充填复垦和矿区生态修复提供参考。

Coal gangue serves as a critical material for landfilling and reclamation in the subsidence areas of coal mines. However, due to its rough textures and poor water-holding capacity, soils reconstructed using coal gangue exhibit somewhat different pore structures and water-salt transport from undisturbed soils. To explore the changes in the pore structure of the reconstructed soils and their effects on water and salt transport, this study analyzed the differences in the pore structures between four samples from undisturbed soils, the overburden, mud-gangue mixtures, and gangue using CT scanning and image analysis. Furthermore, an indoor experimental device was designed to simulate the water and salt transport in reconstructed soil. The sensors arranged at different depths of the device allowed for the continuous recording of the water and salt transport along the profile of the reconstructed soil. The results are as follows: (1) Among the four samples, the gangue sample exhibited the highest porosity, reaching 8.299%, resulting in poor water-holding capacity. The mud-gangue mixture sample manifested a high proportion (58.73%) of small pores, low pore connectivity, and a lack of water transport pathways, leading to the formation of an interlayer barrier zone. The overburden and undisturbed soil samples displayed similar pore structures. (2) In the simulation experiment of a soil column, the salt content in the soils varied with water migration, presenting a trend of a first increase followed by a decrease across all soil layers. Post-infiltration, the topsoils were desalted, while the deep soils showed salt accumulation. (3) Within six days after water injection, the salt content in all soil layers first decreased and then increased, with the most significant changing amplitude, 38.34%, emerging at the 50-cm-deep soil layer. As the salt in the deep soils migrated upward under the action of capillary force, the salt content in the topsoils gradually increased. (4) The presence of the interlayer barrier zone hindered the upward transport of water and salt in the gangue layer, resulting in gradually decreasing contents. The results of this study can serve as a reference for the landfilling and reclamation of mining subsidence areas and the ecological restoration of mining areas.

安徽省高校协同创新项目(GXXT-2021-017)；国家自然科学基金项目(42072201)；安徽省绿色矿山工程研究中心开放基金项目(CXY-2023-0101)；安徽省自然科学基金项目(2208085ME123)

李华焜，郑刘根，陈永春，等. 基于CT扫描的重构土壤孔隙结构及其对水盐运移影响[J]. 煤田地质与勘探，2024，52(4)：1−8.

LI Huakun，ZHENG Liugen，CHEN Yongchun，et al. Exploring the pore structure of reconstructed soils and its effects on water and salt transport based on CT scanning[J]. Coal Geology & Exploration，2024，52(4)：1−8.