The estimation of rock pressure induced by an excavation/cut in sedimentary rocks is addressed in this study. A simplified stochastic model is proposed to model this rock pressure to account for sliding along parallel bedding planes as well as random friction angles on these bedding planes. Simulations show that the classical Rankine and Coulomb theories typically give active pressures much larger than those predicted by the proposed model. A simplified reliability-based design approach is developed to calibrate the required partial factors for the determination of design rock pressure. The proposed approach is demonstrated over a case study for northern Taiwan. Design charts are developed to facilitate the determination of design rock pressures induced by excavation/cut in sedimentary rocks.