Abstract: To investigate the distress mechanisms and remediation measures for the inverted arch structure of existing highway tunnels, this study takes the Yunling Tunnel as the engineering background. Through field investigations and FLAC 3D numerical simulations, the causes of inverted arch heave are systematically analyzed, and the stress distribution and safety factors at various locations of the inverted arch are evaluated. The results reveal that the existing inverted arch structure has already developed cracking and damage. On the basis of enhancing structural stability and safety, three remediation schemes are proposed: (1) reinforcing the inverted arch with strengthened connecting bars, (2) increasing the curvature radius of the inverted arch, and (3) an embedded secondary arch combined with tunnel invert grouting. The reinforcement effectiveness of each scheme is evaluated through numerical simulation. The results indicate that all three schemes reduce the heave displacement of the inverted arch by up to 64.4%, effectively controlling the deformation. Regarding plastic zone volume evolution, each scheme significantly mitigates tensile stress-induced damage to the inverted arch, thereby improving structural stability. Furthermore, all schemes yield varying degrees of improvement in the safety factors at different locations of the inverted arch, enhancing overall structural safety. These findings can serve as a reference for the treatment of inverted arch distress in similar tunnels.