Dewatering Design for the Excavation of a Ship Lock Under Uncertainty from Karst-Conduit Dominated Groundwater Flow

摘要

The presence of Karst-conduits at the ship lock excavation site in Bolzum led to highly uncertainrnpredictions of the groundwater inflows and drawdown evolution during dewatering of the pit. Tornasses the impact of the Karst-conduit-system on the dewatering operations at the relevant scale pumpingrntest was carried out. These conditions demanded for the Observational Method Approach in which therndrawdown is constantly recorded during dewatering and continuously interpreted by a transient groundwaterrnmodel. Injection-schemes outside the pit were developed which allowed limiting a critical drawdownrnbeneath a near by built-up area. The integrated approach of dewatering, iterative updating of therngroundwater model according to observed drawdown and inflow along with previously established contingencyrnactions led to a robust excavation pit without compromising safety.