Characterizing the deep pumping-induced subsidence against metro tunnel using vertically distributed fiber-optic sensing

Continuous pumping of groundwater will induce uneven ground settlement, which may adversely affect the nearby metro tunnels. In this paper, taking Nantong Metro Line 1 crossing Port Water Plant as an example, surface level measurement and subsurface deformation monitoring using vertically distributed fiber-optic sensing are implemented to acquire settlement emergency water supply conditions. The cable buried in constant-temperature layer is used measure strain field deduce amount each stratum. results show that, during pumping, aquifer linearly compressed with time; after continues settle at a slower rate for about 50 days, followed by slow linear rebound, logarithmically rebounded. addition, deep causes aquifers be much greater than settlement; lags behind 1–2 months; rebound recovery also exhibits similar delay. Fitting models were derived predict maximum curvature radius site, indicates that adverse effects against tunnel not negligible once continuous exceeds 15 days. Those insights can referred practitioners control urban subsidence.