Particle size and splitting displacement on particle motion in dynamic water flow crack filling slurry

The fluid physical mechanism of particle size and crack opening affecting cement slurry flow and particle deposition in cracks was studied. Through the dynamic water grouting experiment and numerical simulation of mixed slurry, the verified model shows that compared with the smaller particle (0.03 mm), the larger particle (0.05 mm) increases the deposition amount in the grouting matrix by 34.8%. It is worth noting that the particle deposition concentration increases sharply when the splitting displacement is 1.25 and 2.5 mm. It can be intuitively shown that for 2 s, the particle settlement concentration increases by 69.8% and 81.5% when the splitting displacement is 1.25 mm and the non-splitting displacement is not 1.25 mm, respectively. It is further shown that the grouting flow accelerates when the crack width decreases, accompanied by the increase in turbulence intensity and the significant increase in the collision frequency between the particles and the crack wall. These effects cooperate and intensify the particle deposition in the crack under the combined action of particle size and crack width changes.