Estabilización mecánica del saprolito para uso como núcleo de baja permeabilidad de una presa de relaves bajo un entorno de selva tropical

November 19, 2024

Saprolite soils typically have a natural moisture content between 10% to 25% greater than the optimum moisture content of Standard Proctor tests. This natural condition results in low workability, reduced shear strength, and compaction density, especially in high-rainfall environments. Traditional methods of aeration or mixing with lower moisture content soils can be complex or not applicable due to the climate and humidity in tropical regions. Additionally, reworking saprolite worsens their workability as these soils release trapped water from the chemical weathering bond, resulting in an even higher percentage of moisture. Mentioned adverse conditions were encountered on a project located in the Amazon rainforest region in the northern Andes of South America, which are tied to sustained rainfall throughout the year in an environment with no established "dry" season. The design of the tailings dam considered the saprolite as a low permeability core upstream; the construction of this component was identified as the critical activity to complete the dam on schedule. At the beginning of the dam construction, one of the decisions to improve the strength and workability of the saprolite was to mix this material with low percentages of cement. This article summarizes field observations using cement as an additive for mechanical stabilization of the saprolite to maintain the progress of the dam construction. Furthermore, this report describes and associates as follows: the relationship between results of in situ and laboratory tests, criteria for future guidance in a similar climatic environment, a general description of fill mixture performance, challenges for the borrow area, in situ material mixing, surface water management, equipment, construction techniques, and compaction control for quality assurance.

Barquero, G. and R. Robles. 2024. “Estabilización Mecánica del Saprolito para Uso como Núcleo de Naja Permeabilidad de una Presa de Relaves Bajo un Entorno de Selva Tropical. Mechanical Stabilisation of Saprolite for Use as a Low Permeability Core of a Tailings Dam Under a Rainforest Environment,” in Proceedings of the 17th Pan-American Conference on Soil Mechanics and Geotechnical Engineering (XVII PCSMGE), and 2nd Latin-American Regional Conference of the International Association for Engineering Geology and the Environment (IAEG), La Serena Chile, 2024.