<p>The D-shaped tunnels are widely adopted in underground rock engineering, by considering their efficient spatial utilization and mature construction methodology. A series of experiments were conducted on the granite specimens containing a D-shaped hole to investigate the failure process and underlying mechanisms under combined biaxial compression and low-frequency and moderate-amplitude (LFMA) dynamic disturbances with various principal stress inclinations (<i>θ</i>). The results reveal that the tunnel failure zones gradually migrate from the sidewalls to the springs and corners, and ultimately to the roof and floor as the stress inclination increases from 0° to 90°. Concurrently, the stress threshold of the initial damage increases progressively. The shear behavior is dominant during the disturbance period; however, the tensile fracturing replaces shear to become dominant at the ultimate failure stage, revealed by AE signals. Furthermore, the DIC monitoring shows that the dominant fracture pattern consists primarily of wing-shaped cracks, arc-shaped bands, and secondary cracks. Compared to the straight-walled structure, the arched tunnel exhibits a lower threshold for initial failure stress, making it more susceptible to crack initiation and subsequent fracture. Rockburst events in arched tunnels are also associated with broader damage zones and higher severity. The experimental results from physical model tests demonstrated great consistency with field observations of the deep rock excavation engineering.</p>