Non-conclusive time series analyses-what can we learn on the behavior of the groundwater system? Understanding what caused the collapse of an abandoned drainage tunnel

摘要

Time series analysis was used as an attempt to identify a potential accidental hydro-geological trigger to the collapse of an abandoned mine drainage tunnel in Belgium. Correlation, spectral and wavelet analyses were applied to piezometric data in order to characterize regional-scale hydraulic connections between groundwater bodies, but failed to provide direct insight into regional hydrogeology. No correlation between data collected in the hydrogeological unit of the collapsed area could be identified, showing that the piezometers were tapping isolated sand lenses. As a conclusion, the collapse was rather attributed to a slow increase in water pressure linked to a limited recharge.