Penetration behavior of rock mass under complex geostress conditions: Experimental and numerical study

Acoustic emission technology was used to evaluate geostress and gather information about the rock mass around the test area, after which a rock mass penetration test was performed. In the LS-DYNA software, the initial geostress was incorporated into the model via the dynain file method to calculate the projectile's penetration depth while accounting for this initial stress. The difference between the numerical simulation results and the experimental data was 9%. As geostress increases, the projectile's penetration depth decreases. At lower initial stress levels, changes in initial stress have a significant effect on penetration depth, but as geostress becomes higher, its influence on penetration depth lessens. Within a relatively low range of geostress, the effect on projectile deflection follows a consistent pattern, wherein the extent of deflection corresponds to the differential stress exerted on either side of the projectile during penetration. When the target inclination angle is below 20°, variations in ballistic deviation across different geostress levels are negligible. Conversely, for target angles exceeding 20°, an increase in ground stress markedly intensifies the divergence between the projectile’s trajectory and its original penetration path.