In the field of tunnel construction, the relationship between the tunnel lining and the rock mass above plays a crucial role in maintaining the stability and security of the tunnel, particularly in cracked rock masses. The distribution of stress at the edge of the crack is subject to alteration due to variables such as the ambient rock stress levels, the angle at which the crack occurs, the length of the crack, and the coefficient of friction along the crack surfaces, all of which have a direct impact on the plastic zone’s distribution at the crack’s tip. A comprehensive understanding of the plastic zone is vital for comprehending and forecasting the interplay between the tunnel lining and the surrounding rock. This study primarily focuses on a theoretical examination of the plastic zone existing within the rock mass overlying tunnel linings, evaluating its dimensions, and applying the Von Mises yield criterion to characterize its shape. Furthermore, the study takes into account the impact of the ambient rock stress, crack inclination, crack length, and the friction between crack surfaces on the plastic zone’s configuration.