华北型煤田深部开采过程中受底板灰岩含水层水害威胁程度高，通过合理布设注浆孔向直接威胁煤层安全开采的含水层大量灌注浆液，使强含水层成为弱含水层或隔水层，是解决此类水害问题的主要手段。在微裂隙注浆工程中，浆液–岩体耦合效应对浆液扩散过程影响显著。为此，开展煤层底板裂隙含水层高压注浆过程中浆液–岩体相互作用及浆液扩散机制问题研究，基于黏度时变性宾汉流体浆液扩散运动方程和裂隙开度控制方程，建立了考虑浆液流动与岩体变形耦合作用的裂隙注浆扩散理论模型，分析了浆液压力和裂隙开度在浆液扩散方向上的空间分布特征，揭示了浆液–岩体耦合作用对浆液扩散的影响规律，并利用恒定裂隙开度注浆模型进行了对比分析。结果表明：浆液压力和裂隙开度变化在浆液扩散方向上衰减趋势一致且均具有明显的非线性特征，在裂隙入口区域衰减较快；浆液–岩体耦合作用程度随裂隙开度增加而减小，裂隙开度较小时不考虑浆液–岩体耦合作用将导致注浆压力设计值偏大；随着裂隙开度增加，注浆压力逐渐成为影响浆液扩散距离的主控因素。最后，结合鲁西煤矿下组煤底板灰岩含水层注浆改造工程实例，验证了理论模型的正确性。

The deep mining process of North China type coalfields is highly threatened by the threat of water damage from the floor limestone aquifer. By arranging grouting holes reasonably to inject a large amount of slurry into the aquifer that directly threatens the safety of coal seam mining, making the strong aquifer a weak aquifer or an impermeable layer is the main means to solve such water damage problems. In microfracture grouting engineering, the slurry-rock mass coupling effect has a significant impact on the diffusion process of slurry. To this end, the interaction between slurry and rock mass and the diffusion mechanism of slurry during high-pressure grouting of coal seam floor aquifers was studied, a single fracture grouting diffusion theoretical model was established that considers the slurry flow-rock mass deformation coupling effect, based on the viscosity time varying Bingham slurry diffusion equation and fracture aperture control equation. The spatial distribution characteristics of slurry pressure and fracture aperture in the slurry diffusion direction were analyzed, and the effect rules of slurry-rock mass coupling effect on slurry diffusion was revealed, and the results were compared with the grouting model with constant fracture aperture. The results showed that the attenuation trend of slurry pressure and fracture aperture in the slurry diffusion direction was consistent, and both had obvious nonlinear characteristics, and the attenuation was faster in the fracture entrance area. The degree of slurry-rock mass coupling effect decreased with the increase of fracture aperture, and the design value of grouting pressure will be too high if fracture aperture was small and the slurry-rock mass coupling effect was not considered. The grouting pressure became the main controlling factor affecting the slurry diffusion distance gradually as the fracture aperture increased. By comparing the theoretical results with an example of grouting transformation of the limestone aquifer in the lower coal seam floor of Luxi coal mine, the validity of the theoretical model was verified.