Diffusion mechanism of cement-based slurry in frozen and thawed fractured rock mass in alpine region

The problem of slope stability after freeze-thaw damage in cold regions has become increasingly prominent. To explore the grouting diffusion mechanisms of different grouting materials in frozen and thawed rock masses, a true triaxial stress-state frozen and thawed rock mass fracture grouting experiment was conducted. Computed tomography (CT) and scanning electron microscopy (SEM) were performed on the grouted specimens to obtain the grouting diffusion patterns and three-dimensional reconstruction of the grout veins in different frozen and thawed rock masses under fracture grouting. The results show that Portland cement slurry with low viscosity has better diffusion performance in unfrozen rock mass and rock mass after 10 freeze-thaw cycles. In the case of cement slurry containing graphene oxide and microsilica powder additives, the reinforced area exceeded that of ordinary cement after 10 freeze-thaw cycles, with the reinforced area reaching its maximum after 25 cycles. The "slurry-rock" interface primarily forms three modes: contact, embedding, and covering. Graphene oxide and microsilica effectively fill the larger pores in the cement particles, with microsilica being particularly effective in promoting cement hydration and reducing microdefects in the transition zone between the slurry and rock interfaces.