Abstract
This paper presents a case study on the use of Ralph Peck’s observational method on a historic upstream-raised tailings dam, which was identified as vulnerable to flow liquefaction. The dam is 75 m high from toe to crest, with the upper 25 m constructed using the upstream raise method. To mitigate the risk of failure, a reinforcing earth buttress was designed and built on the downstream face of the dam. The application of Peck’s method in both design and construction involved several key principles, including the assessment of the most probable and most unfavorable conditions, the development of the design, selecting specific quantities to monitor during construction, evaluating the selected quantities under different hypothetical conditions, the development of an alternative plan in case observed values diverge from the predictions, and monitoring of the selected quantities for the actual conditions during construction. Numerical simulations using the finite element method were employed to predict the dam’s performance during buttress construction. Construction was completed successfully, with observed deformations and pore pressures generally lower than anticipated. The paper highlights the effectiveness of this approach in managing tailings storage facilities at risk of flow liquefaction.
