Application of excavation compensation method for enhancing stability and efficiency in shallow large-span rock tunnels

Engineering shallow, large-span rock tunnels challenges deformation control and escalates construction costs. This study investigates the excavation compensation method (ECM) and its associated technologies to address these issues. Utilizing five key technologies, the ECM effectively modulates radial stress post-excavation, redistributes stress in the surrounding rock, and eliminates tensile stress at the excavation face. Pre-tensioning measures further enhance the rock's residual strength, establishing a new stability equilibrium. Field tests corroborate the method's effectiveness, demonstrating a crown settlement reduction of 3-8 mm, a nearly 50% decrease compared to conventional construction approaches. Additionally, material consumption and construction duration were reduced by approximately 30%-35% and 1.75 months per 100 m, respectively. Thus, the ECM represents a significant innovation in enhancing the stability and construction efficiency of large-span rock tunnels, marking a novel contribution to the engineering field.