Experimental study on viscosity transient modified cement-based magnetic slurry and multi-inclination grouting of fractures

The existence of fractures poses a huge challenge to the stability and safety of the surrounding rock of underground engineering. However, conventional grouting materials are prone to loss in inclined fractures, resulting in poor grouting filling effects. Based on the self - developed polymer - modified cement - based magnetic slurry (EMCM), this paper uses testing methods such as SEM (scanning electron microscope), digital viscometer, and digital tensiometer to analyze the solidification mechanism of the EMCM slurry, study the chain - formation evolution process of magnetic particles and the force conditions of magnetic particles under a magnetic field, and clarify the influence mechanism of magnetic field strength on the transient effect of dynamic viscosity. The grouting diffusion of the EMCM slurry in fractures under the action of a magnetic field is systematically studied. The results show that the core reaction of the modification of the cement - based EMCM slurry by epoxy resin is the reaction between free calcium ions and - OH. Using calcium ions as nodes, a complex polymer cross - linked network structure is formed. The main reason why the EMCM slurry has the characteristic of transient viscosity change is the change in the force between the magnetic particles in the slurry under the magnetic field. The action of the magnetic field helps to increase the diffusion area of the EMCM slurry in fractures and the slurry retention rate. Compared with pure cement slurry, the EMCM slurry under the action of a magnetic field has obvious advantages in fracture grouting and has broad research potential and application prospects. • Revealed the modification mechanism of polymers on cement-based magnetic slurries. • Elucidation the chain-formation evolution of magnetic particles in EMCM under a gradient magnetic field. • Increase in magnetic field strength helps to enhance the diffusion area of EMCM slurry.