Monitoring and assessment of mechanical response of large-scale prefabricated structures in underground subway stations during construction process

Abstract

Mechanical performance of prefabricated structural components during construction is critical for ensuring long-term safety and durability of prefabricated underground stations (PUS). This study aims to address the issues of structure mechanical performance of large-scale prefabricated components during assembling process. First, a strain transfer model for five-layered armored fiber optic is proposed and validated experimentally through test. Second a PUS-based distributed fiber optic sensors (DFOS) monitoring system was established. Third, a PUS based hierarchical performance assessment framework was constructed. Finally, a PUS based theoretical Construction Intelligent Monitoring Assessment Model (CIMAM) was established to quantitively assess structure safety level. A case study of Shenzhen Metro PUS was performed, and the results showed that: (a) PUS-based DFOS monitoring system presents high accuracy and high resolution, (b) The monitoring system reflects the PUS reactions during the whole construction process with good adaptability and intelligence, (c) PUS-CIMAM results show that the assembly process of components is a significant control link, particularly the performance of large-span roof during assembling process is a key controlling component, and (d) PUS-CIMAM reveals the adjacent ring construction has a disturbing effect.