Dynamic response characteristics, load-bearing efficiency in multimaterial tunnel assemblies subjected to recurrent...

Area of Science:

• Civil Engineering
• Structural Engineering
• Materials Science

Background:

• Reinforced-concrete tunnels face risks of hydraulic leakage and reduced load capacity post-cracking.
• Metal liners can experience instability under high external pressures.

Purpose of the Study:

• To propose and evaluate a multilayer lining concept for reinforced-concrete tunnels.
• To mitigate hydraulic leakage and maintain load-carrying capacity after cracking.
• To reduce instability concerns associated with conventional liners.

Main Methods:

• Physical model tests were conducted on a multilayer lining (inner concrete, steel plate, outer concrete).
• Tests involved alternating external and internal pressurization cycles.
• Circumferential stress evolution and load-transfer paths were quantified.

Main Results:

• Under external pressure, concrete layers carried most hoop action, with the steel plate well below buckling limits.
• Internal pressurization and concrete cracking caused significant load redistribution to the steel plate.
• The steel plate effectively handled alternating tensile-compressive stresses, preserving global integrity post-damage.

Conclusions:

• The multilayer lining demonstrates enhanced resistance to hydraulic loading and improved structural robustness.
• This design is suitable for high-head conveyance tunnels, offering superior performance over conventional schemes.