<p> To gain an in-depth understanding of the failure characteristics and reinforcement mechanisms of the anchorage layer in tunnel, a series of loading failure experiments were conducted. By isolating the anchorage layer, its bearing capacity was effectively quantified. This study systematically examined the stress, deformation, and failure characteristics of the surrounding rock under unsupported conditions (surrounding rock layer, SRL), anchor bolt support (anchorage layer, AL), and pre-tensioned anchor bolt support (pre-tensioned anchorage layer, PAL). Furthermore, the incorporation of P-wave velocity (<i>V</i>_p) and PIV testing provided a robust framework for elucidating the reinforcement mechanisms of the anchorage layer. The failure of SRL initiated at the tunnel shoulders, whereas for AL and PAL, failure originated at the tunnel crown. The <i>V</i>_p at the tunnel crown of PAL and AL exhibited increases of approximately 11.0% and 7.6%, respectively, compared to SRL. The failure displacement of PAL and AL was observed to be 3.18 and 1.87 times greater than that of SRL. The installation of anchor bolts modulated the stress distribution within the surrounding rock, thereby enhancing its integrity and ultimately leading to a notable improvement in the ductility and overall bearing capacity of the surrounding rock.</p>