96 publications from this institution
In the present research a new non-lineal failure criterion in rocks called GIT criterion is established. The new criterion has been developed by the Ground Engineering Group from the University of Oviedo (Spain), and it can be expressed in terms of both normal and shear stresses (σn,τ), and principal stresses (σ3, σ1 ). Three characteristic parameters define the criterion, which are estimated applying nonlinear least squares regression methods, using the Levenberg-Marquardt (LM) algorithm. The novelty of this new criterion is that its determination can be carried out only by using uniaxial compression tests, which are more economic and easier to implement than triaxial tests. The theoretical formulation is accompanied by set laboratory tests, and the results obtained are compared with the classical criteria employed in rock mechanics, such as those of Mohr-Coulomb and Hoek-Brown.
This paper shows the possibility that the mineral coal existing in the mining basins of northern Spain have a high added value.This would facilitate its future use in different fields such as new materials, nanotechnology, energy use in situ, coal bed methane, enhanced coal bed methane and coalmine methane.An analytical study of mineral coal samples is carried out.The samples come from two deposits located in coal basins of the Cantabrian Mountains.The duly prepared samples are subjected to an activation process.Within this transformation, different treatments are applied to different sub-samples.Some of the sub-samples suffer a previous demineralization by successive attacks with acids, followed by oxidation and pyrolysis.Finally, all of them are activated with CO 2 and H 2 O (steam) .The carbonaceous products resulting from each treatment are characterised.The results show that all the pre-treatments used were positive for the textural development of the materials.Likewise, proper management of the processes and of the different operating variables allows the procurement of carbonaceous materials with a "tailor-made" structural development of the coal type.This material receives the name "activated" and can be employed in specific processes.
In this work, the sup port of two general galleries located in poor quality rock mass and subjected to the influence of high thickness coal layer exploitations is designed and optimized.The process is carried out in four phases:A first preliminary support is defined employing different geomechanical classifications and applying the New Austrian Tunnelling Method (NATM) using bolts and shotcrete.An instrumentation campaign is carried out with the goal of analysing the behaviour of the support.The study noticed the failure of the support due to the time of placement of the different elements.A back-analysis using the Flac and Phases software has allowed the evaluation of the properties of the rock mass and the support, the study of the influence of the time of placement on the component elements (bolts and shotcrete), and the redefinition of that support.Subsequently, a new support is designed and optimized through numerical modeling after the start of mining without experience in these sizes of sublevel caving that caused the failure of the previously designed support.The new support is formed by yieldable steel arches that are more suitable to withstand the stresses generated by nearby mining work.
The combination of methane - air can cause potentially explosive mixtures, which in contact with an energy source can ignite, resulting not only in the destruction of infrastructure but also in the death of people. The aim of this paper is to study the ignition of methane - air mixtures with different concentration of methane, as a function of the ignition sources used and the volume and geometry of the explosion chamber. For this purpose, the 'Dynamic Behaviour of the Rock mass (DinRock)' research group of the University of Oviedo has designed and manufactured 3 explosion chambers of different sizes and shapes, instrumented with dynamic pressure sensors and accelerometers. In addition, the ignition process has been recorded with a high-speed camera. With the results obtained after a laboratory-scale experimental campaign, the maximum pressure reached, the pressure gradients and the acceleration of the pressure waves were analysed. Thus, it has been determined that the maximum pressure reached is independent of the ignition source used and the chamber volume, but not of the chamber geometry. Methane (CH4) concentrations between 8.0 and 9.0% generated the highest pressures between 1.5 and 2.5 MPa. A correlation between peak acceleration and peak pressure has also been established allowing to identify whether a deflagration or a detonation has occurred.
There is no doubt that additive manufacturing (AM) with mortars presents an opportunity within the framework of a circular economy that should not be overlooked. The concepts of reduce, reuse, and recycle are fully aligned with this technology. One of the less explored possibilities is the utilisation of mining tailings as aggregates in printing mortars. This idea not only incorporates the concept of recycling but also contributes to a reduction in the production of potentially hazardous waste that would otherwise require storage in dams, thereby decreasing long-term environmental risks and improving the management of mineral resources. We employed a mortar composed of 12.5% material derived from mining tailings to highlight aspects of AM that are typically not subject to analysis, such as the necessity of considering contact interfaces between layers in structural design, the stackability of layers during the construction process, and the behaviour under fire and seismic events, which must be taken into account during the operational phase. Without aiming for exhaustiveness, we conducted a series of tests and computational modelling to show the significance of these factors, with the intention of drawing the attention of different stakeholders—including construction companies, regulatory authorities, standardisation agencies, insurers, and end-users.
