In this paper, the penetration of a high-speed conical rigid projectile into a rock mass was simulated using the 3D discrete element method with particle flow capability. In order to simulate the rock mass and the projectile, discrete spherical elements were used, and a parallel bond behavioral model with force and moment transfer capability was used to connect the spherical particles. The values ​​of the microparameters of the parallel bond model were calibrated by performing numerical simulations of a uniaxial compression test of the rock mass. In the projectile impact simulation for the rock mass of the Bakhtiari Power Plant's Moghar construction site, the crushing of the rock mass and the ejection of its pieces at high speed were well modeled. The results showed that large compressive and shear stresses are induced by the impact on the rock mass. The effect of parameters such as the initial velocity of the projectile, the shape of the nose, its weight, and its slenderness ratio (diameter/length) on the penetration of the projectile was also investigated. In order to validate the method used, the results were compared with analytical relations, and a very good agreement was observed between the results.