To reveal the flow characteristics of shotcrete during pneumatic transportation, the numerical simulation of the gas–solid flow of shotcrete in the pipeline transportation process was carried out based on a CFD-DEM coupling simulation method. When the particle diameter increased from 7 mm to 12 mm, the maximum wear depth of the pipeline increased from 1.48 × 10⁻⁶ mm to 4.58 × 10⁻⁶ mm. With an increase in particle diameter, the maximum wear depth of the pipeline increased. Moreover, the wear position gradually concentrated to a fixed area with the increase in particle diameter. In the wind speed range of this simulation study, when the wind speed increased from 42 m/s to 52 m/s, the maximum wear depth of the pipeline increased from 2.53 × 10⁻⁶ mm to 5.26 × 10⁻⁶ mm. The change in wind speed had little effect on the wear location of the pipeline. However, the wear depth of the pipeline increased with the increase in wind speed. When the curvature radius increased from 200 mm to 250 mm, the maximum wear depth decreased from 5.83 × 10⁻⁶ mm to 4.47 × 10⁻⁶ mm. When the curvature radius increased to 300 mm, the maximum wear depth increased to 6.58 × 10⁻⁶ mm. Finally, according to the law of pipeline wear and combined with the actual situation of pipeline wear in engineering, measures were put forward to prevent or reduce the degree of pipeline wear.

In the continuous development and application of underground spaces (such as roads, tunnels and underground caverns), safe and efficient support technology is an important means to maintain the stability and integrity of roadways