China Coal Energy Research Institute Co., Ltd., Xi'an, China.
School of Energy and Mining Engineering, China University of Mining and Technology(Beijing), Beijing, China.
PLoS One. 2023 Feb 24;18(2):e0282190. doi: 10.1371/journal.pone.0282190. eCollection 2023.
The filtration effect significantly affects the gangue slurry velocity and concentration, making it difficult to evaluate the gangue slurry diffusion range. Based on the Darcy seepage law, a seepage theoretical calculation model is established considering the filtration time and space effect. And the "water-cement ratio change matrix" in the seepage process of coal gangue slurry is deduced, revealing the basic mechanism of the porous media filtration effect, and the water-cement ratio gradually increases in the seepage process of gangue slurry. The visual test platform for slurry diffusion in goaf was independently developed for testing. The active heating optical fiber method (AHFO) was used to monitor the flow and diffusion of coal gangue slurry in the collapse zone of goaf, and the gravity gradient and water cement ratio of slurry in goaf were measured. The law of particle sedimentation in the gangue slurry flow process under the filtration effect was revealed, and engineering verification was carried out. The results show that the average slope of the gangue slurry in the gangue accumulation is 6.34%, and the overall flow law of the gangue slurry in the goaf is the first longitudinal expansion and then transverse diffusion. The water-cement ratio near the grouting mouth is smaller than the initial water-cement ratio, the near-end water-cement ratio is smaller, and the far-end water-cement ratio is larger. During on-site filling, the accumulated grouting volume of a single hole is 700 m3, and the gangue slurry diffusion distance is greater than 45m, indicating that the gangue slurry has good fluidity.
过滤效应显著影响了矸石浆的流速和浓度，难以评估矸石浆的扩散范围。基于达西渗流定律，考虑过滤时间和空间效应，建立了渗流理论计算模型。并推导了煤矸石浆渗流过程中的“水灰比变化矩阵”，揭示了多孔介质过滤效应的基本机理，水灰比在矸石浆渗流过程中逐渐增加。自主开发了用于测试的采空区浆液扩散可视化测试平台。采用主动加热光纤法（AHFO）监测采空区冒落带中煤矸石浆的流动和扩散，并测量了采空区中浆体的重力梯度和水灰比。揭示了过滤效应下矸石浆流动过程中颗粒沉降规律，并进行了工程验证。结果表明，矸石堆积处矸石浆的平均坡度为 6.34%，采空区矸石浆的整体流动规律为先纵向膨胀再横向扩散。注浆口附近的水灰比小于初始水灰比，近端点水灰比较小，远端水灰比较大。在现场充填过程中，单孔累计注浆量为 700m3，矸石浆扩散距离大于 45m，表明矸石浆具有良好的流动性。
