<p>A multilayer lining concept is proposed to mitigate hydraulic leakage risk and loss of load-carrying capacity after cracking in reinforced-concrete tunnels, while also reducing instability concerns typical of metal liners under elevated external pressures. The configuration comprises an inner reinforced-concrete ring, an intermediate steel plate, and an outer concrete ring, forming a cooperative load-resisting assembly. Physical model tests were carried out under alternating external and internal pressurization to quantify circumferential stress evolution and the associated load-transfer path. Under external pressurization, the inner concrete, steel plate, and outer concrete sustained approximately 40%–42%, 13%–16%, and 43%–45% of the resultant hoop action, respectively, and the steel plate remained substantially below the buckling demand, indicating a stable compression regime within the tested range. Under internal pressurization, progressive cracking of the concrete rings triggered a marked redistribution of hoop force toward the steel plate; its load fraction increased from 15% to 25% following inner-ring cracking and from 14% to 26% following outer-ring cracking. Across the two pressurization cycles tested, the steel plate maintained the capacity to carry alternating tensile–compressive demands, thereby preserving global integrity after concrete damage. Overall, the proposed multilayer lining exhibits improved resistance to limited-cycle hydraulic loading and enhanced structural robustness relative to conventional lining schemes, supporting its applicability to high-head conveyance tunnels.</p>