Analysis and Countermeasures for Interlayer Pressure Issues in Double-Layer Metal Expansion Joints

To investigate the mechanisms of interlayer pressure issues in double-layer metal expansion joints and develop effective countermeasures, this study quantitatively analyzed the relationships between temperature variations, chamber water ingress, and interlayer pressure changes using the ideal gas law and the Antoine equation, based on practical observations. The study revealed the underlying mechanisms of three types of pressure issues: Elevated interlayer pressure during thermal operation stems from air expansion due to heating; post-shutdown pressure reduction results from gas contraction during cooling; and interlayer water ingress leads to significant pressure surges, posing overpressure risks to the expansion joint. Strategies such as preventive maintenance, interlayer pressure management, and measures to prevent water ingress were proposed, providing theoretical support and practical guidance to ensure the reliability and safe operation of expansion joints.