Study on Influence Law of Key Factors of New Composite Slurry Spraying Technology

In this paper, a new type of water pressure and air pressure composite slurry is proposed to ensure the safety of spraying. Firstly, the air tightness, bending resistance and viscosity of the spraying material were measured in the laboratory. Secondly, the two-fluid VOF model was used to analyze the influence laws of the spraying process, the spraying area formed on the wall, the thickness of the spraying layer and the pressure at the nozzle (or initial flow rate), the spraying distance, the spraying time, and the spraying direction. The research shows that (1) the new composite slurry spraying material made of clay:cement:additive:engineering fiber = 84:14:1.85:0.15 has suitable sealing and bending resistance and adhesion. (2) The smaller the spraying distance is, the larger the spraying area formed on the side wall in a short time, and the shape is regular, but the spraying area is relatively small. The spraying area increases with the increase in spraying distance, and the slurry thickness becomes thinner with the increase in spraying distance. (3) When the initial spraying speed is high, the shape of the spraying area is regular, the spraying thickness is large and the uniformity is suitable, but the shape and uniformity of the spraying area are related to the time when the slurry reaches the side wall. The longer the time when the slurry reaches the side wall, the greater the influence of gravity and surrounding fluid, and the more changes along the process. (4) When the spraying surface is at the top, the spraying process is significantly affected by gravity, and discontinuous spraying areas will be formed on the top surface. Especially when the initial spraying speed is low, the amount of slurry reaching the top surface fluctuates due to rebound and increases with the increase in the initial spraying speed.