Modal parameters are of great significance in civil engineering because they can characterize the properties of structures and be used for vibration control and structural health monitoring.Subway tunnels are long lin...Modal parameters are of great significance in civil engineering because they can characterize the properties of structures and be used for vibration control and structural health monitoring.Subway tunnels are long linear truss structures combined with the mutual cou-pling of the surrounding soil.Therefore,the operational modal analysis of a mutual coupling tunnel is complicate,as is the modal iden-tification of shield tunnels in a time–frequency domain,and these are hot civil engineering topics.Using the shield tunnel of Shanghai metro line No.12 project as a case study,we carried out the vibration response monitoring of a subway tunnel during operation and presented methods to identify structural modal parameters.The modal parameters of lower vibration modes were estimated using response measurements.Modal frequencies and shapes were identified with high precision and accuracy using the orthogonal polynomial clustering algorithm under hammer excitation conditions and the autoregressive-moving-average model under ambient excitation con-ditions.The dynamic behavior of a mutual coupling tunnel presented obvious low frequency characteristics,and the first 9th order mode frequencies were less than 100 Hz.The diagonal values of the modal assurance criteria were all greater than 0.85.The modal parameters can be used for the health monitoring of operational subway tunnels.展开更多
基金supported by National Key R&D Program of China(Grant No.2019YFC0605103)National Natural Science Foundation of China(Grant Nos.51978431,52008214)Science and Technology Foundation of Jiangxi Provincial Transportation Department(Grant No.2020Z0003),China.
文摘Modal parameters are of great significance in civil engineering because they can characterize the properties of structures and be used for vibration control and structural health monitoring.Subway tunnels are long linear truss structures combined with the mutual cou-pling of the surrounding soil.Therefore,the operational modal analysis of a mutual coupling tunnel is complicate,as is the modal iden-tification of shield tunnels in a time–frequency domain,and these are hot civil engineering topics.Using the shield tunnel of Shanghai metro line No.12 project as a case study,we carried out the vibration response monitoring of a subway tunnel during operation and presented methods to identify structural modal parameters.The modal parameters of lower vibration modes were estimated using response measurements.Modal frequencies and shapes were identified with high precision and accuracy using the orthogonal polynomial clustering algorithm under hammer excitation conditions and the autoregressive-moving-average model under ambient excitation con-ditions.The dynamic behavior of a mutual coupling tunnel presented obvious low frequency characteristics,and the first 9th order mode frequencies were less than 100 Hz.The diagonal values of the modal assurance criteria were all greater than 0.85.The modal parameters can be used for the health monitoring of operational subway tunnels.
