96 publications from this institution
Due to the heterogeneity of rocks, their tensile strength is around 10% of their compressive strength, which means that breakage is mainly caused by tensile stress. The measure of tensile stress is very difficult due to rock fragility, so it has usually been measured by indirect measurement methods , including the Brazilian test. However, recent works indicate that the tensile strength values obtained through the Brazilian test must be increased by almost 26%. To understand this divergence, indirect tensile tests have been monitored. The aim is to know the material deformation and load increase by means of stepwise regression. Stress fields in slightly deformed samples are analyzed and modeled (3D finite differences) with loads applied on flat and curved plates and different Young's modulus. Finally, the results are analyzed and compared with strength values reported using Timoshenko theory and Hondros' approximation.
En la actualidad, son cada vez mas las canteras de roca ornamental ?explotadas tradicionalmente a cielo abierto? que, debido a condicionantes de tipo tecnico, ambiental, social o economico, estan planteando la posibilidad de ser explotadas mediante labores de interior. Este es el caso de Pizarras Gallegas, S.A. que, en colaboracion con el grupo de Ingenieria del Terreno de la Universidad de Oviedo, esta llevando a cabo una serie de proyectos de investigacion para determinar la idoneidad de explotar su yacimiento de pizarra del Barco de Valedoras (Orense) mediante laboreo subterraneo. En este articulo se describen las caracteristicas del proyecto.
Being thermal coal such an abundant resource in Spain, we are looking for alternative uses for it. This would enable its future use in different fields, same of them already classic, such as: new materials (graphene, activated carbon, molecular sieves, etc.), nano-technology, in situ energy use (gasification and liquefaction), CBM (coal bed methane), ECBM (coal bed methane with CO2 injection) and CMM (coal mine methane). It could also be used in other innovative areas with high added value, such as gastronomy and biomedicine.
Fractured rock masses below the water table are a problem in underground excavations because of their low strength and high permeability. Nowadays, these negative connotations can be reduced with techniques such as injection of cement, microcement, or resins grouts. These materials increase the rock mass cohesion while reducing the flow of water through the discontinuities. This paper describes the work carried out to design a waterproofing screen for a three-storey underground basement located in a building near the Bilbao estuary (Northern Spain) and with problems of water seepage from the river. First, a survey of the rock mass is carried out. This survey shows the presence of highly fractured zones and the variability of the permeability as functions of the fractures. Subsequently, the effect on permeability caused by the injection of cement grouts and microcement is studied by means of two pilot injection boreholes and eight control boreholes. Finally, a behavioural model is proposed to explain the heterogeneity observed in the radius of influence of the injection. As a result, a waterproofing screen with three types of treatment is designed: An ordinary treatment with cement grouts, an intensive treatment with microcement grouts, and an isolation treatment with cement-bentonite grouts.
