Application of Advanced Multi-Parameter Monitoring in Concrete Structure Defect Detection: Integrating Thermal Integrity Profiling and Strain Analysis

Thermal Integrity Profiling (TIP) effectively monitors concrete integrity. TIP detects structural defects and locates them through anomalies in hydration–temperature curves. However, TIP alone cannot accurately identify the defect types. To resolve this limitation, strain monitoring is integrated with TIP. A dual-parameter temperature–strain monitoring system using fiber-optic sensing was implemented in a diaphragm wall of Weizishan Station, Jinan. This study investigated the spatial distribution and variation patterns of concrete temperature–strain during the different stages of hydration. A thermal–mechanical–chemical multi-field coupling model was established based on the concrete mix ratio and the theoretical thermal parameters, and its feasibility was verified. This study also analyzed the impact mechanisms of four defect types—voids, mud inclusions, necking, and widening—on the surrounding concrete’s heat release and deformation during hydration. It presents specific hydration–temperature–strain characteristic curves that can accurately differentiate the defect types and established the correspondence between the defect types and these characteristic patterns. Finally, a rapid and accurate defect identification process is proposed for practical application, improving efficiency and precision in detecting anomalies. The findings provide a reference for implementing appropriate defect prevention and remediation measures on-site and hold promise for enhancing the prediction and control of defects during the hydration period of concrete structures.