2024 年 10 巻 32 号 p. 1212-1217
The rising world demand for minerals and metals that can only be obtained through mining is increasing the number and size of tailings deposits, which may pose serious social, economic and environmental risks if unproperly managed. This is particularly true in seismically active regions, where the dynamic loading imposed to these structures may result in dramatic failures. In order to clarify the behaviour of these unconventional geotechnical materials under different loading conditions that may occur in situ, advanced geotechnical experiments must be carried out on representative samples. Because undisturbed samples are seldom available, reconstituted samples usually provide an appropriate mean to prepare comparable samples for testing. This paper discusses the effects of sample reconstitution procedures on the mechanical behaviour of iron ore tailings, with particular focus on the undrained cyclic behaviour. The reconstituted samples are prepared using a slurry-based method using different water content values representing possible field depositional conditions found in tailings dams, to assess the effect of the slurries’ water content on the characteristics and undrained mechanical behaviour of the samples. The behaviour of undisturbed samples from a Portuguese iron mine is used to evaluate if the behaviour of the reconstituted samples replicates, at least qualitatively, the real behaviour of the tailings. The research suggests that the characteristics and the undrained mechanical behaviour of reconstituted samples depend on the value of the slurry water content used in the reconstitution, larger water content values possibly promoting particle segregation during reconstitution and producing samples with mechanical behaviour which is less comparable to the behaviour shown by undisturbed samples.
