Underground structures are becoming increasingly important in modern society, promoting the development of efficient and reliable infrastructure networks, especially in metropolises and densely populated areas. Given the growing mileage of underground structures designed for public transportation, such as metro tunnels, the development of Structural Health Monitoring (SHM) strategies capable of ensuring structural integrity, efficient operational conditions and user safety is paramount. Several monitoring techniques have already been proposed, both traditional and innovative, as well as static and dynamic approaches. However, the vibration-based methods developed for this type of structure are relatively few and often require the knowledge of a large amount of data from the monitored structure.