ABSTRACT

In Rio de Janeiro, Brazil, a 17 km long pipeline had been in use since early nineties to transport heated (95°C) oil from the main local refinery to ships. In January 2000 a large-scale environmental accident occurred when this pipeline failed and 1 million litters of oil spilled into Guanabara Bay. Detailed studies confirmed the integrity of the steel used and no evidences of corrosion. In situ piezocone and vane tests were carried out, as well as laboratory studies included triaxial and oedometer tests and soil characterization. Numerical analyses carried out took into account physical and geometrical nonlinearities. It was concluded that the cause of the failure was plastic local buckling of the free pipeline supported at the offshore extremity by the silted soil layer and at the onshore extremity by the remaining soft clay cover.