Experimental and numerical analysis of desiccation of a mining waste

Abstract

The paper presents an analysis of the desiccation process in mining materials, based on physical laws. Due to the process complexity, most of the previous approaches used have an empirical basis. In this case, however, a formulation using coupled hydromechanical equations has been considered. To show the capabilities of the theoretical framework, several laboratory tests were performed, and afterwards a numerical simulation of the measured variables was attempted. The material tested was a metallurgical waste in tailings form and it was exposed to atmospheric desiccation. Further cracking will eventually change its properties, and this may have an environmental impact. Some of the experiments were devoted to material characterization, including the water retention curve, the hydraulic conductivity, and the tensile strength. In addition, laboratory drying tests open to the atmosphere or in hermetically closed containers were also performed. The numerical analyses carried out attempted to simulate some of these tests. One of the main outcomes of the analyses was the prediction of the time and the location of crack initiation. Finally, it should be pointed out that good agreement between the experiments and numerical simulations indicates that the formulation is taking into account the fundamental mechanisms involved in the desiccation process.Key words: desiccation, drying cracks, unsaturated soils, waste material, coupled phenomena, modelling.