As we develop more underground spaces and insert deeper piles, what effect does excavation-induced ground movement have on nearby tunnels?“Performance monitoring of a curved shield tunnel during adjacent excavations using a fiber optic nervous sensing system,” an article by Hong-Hu Zhu, De-Yang Wang, Bin Shi, Xing Wang, Guang-Qing Wei, describes how a fiber optic nervous system (FONS) based on Distributed Fiber Optic Sensing (DFOS) provided continuous monitoring of a curved tunnel during 22 months of adjacent deep excavations.
The tunnel health condition was monitored both longitudinally and circumferentially for strain changes. Those changes are described and classified into Tunnel risk assessment grades, indicating one item to be immediately repaired and an area to be monitored closely.
This valuable insight into the deformation in the tunnel linings is used pragmatically in the tunnel’s management. The conclusions include a glimpse into what else could be monitored by FONS.