LIQUEFACTION FLOW SLIDES AT VALE’S ORE EXPORT TERMINAL, BRAZIL

摘要

Vale is currently completing construction of Pier IV which is a two berth extension to their marine export facility at Ponta da Madeira in northern Brazil. Ongoing monitoring of bathymetry through frequent hydrographic surveys of the project area has provided evidence for frequent and large slope failures inshore of the berths at Pier IV in the form of large scour areas on the slope of the retro area and large depositional zones (of similar quantity) offshore of the pier. Examination of the surveys and other evidence point to liquefaction flow slide events that occur in a matter of minutes without prior warning. This paper describes the development of a Liquefaction Risk Mitigation Dredging Plan for the Pier IV facility through an in-depth analysis of historic cases and the monthly bathymetric surveys. Numerical modelling of liquefaction flow runout was also completed to investigate the extent of sediment runout and its interaction with the structure and berthing operations.