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Fernandez E.,Dragados | Sauer G.,Dr Sauer Corporation
Proceedings - Rapid Excavation and Tunneling Conference | Year: 2013

Tunneling is one of the industry's solutions to improve our environment and consequently Quality of Life. Putting infrastructures and services underground definitely contributes to a more pleasant urban surface. But how to minimize its long-term construction impact and the "high risk/cost" myth? The authors are trying to identify preconceptions in this particular industry and offering more reliable approaches in terms of cost and schedule based on an overall control mechanism.

Parrilla P.R.,Zona Cono Sur DRAGADOS | Espinoza J.,Besalco Construcciones | Palma A.,SRK Consulting Chile S.A. | Gonzalez E.F.,Dragados
Revista de Obras Publicas | Year: 2012

In 2008 a new type of TBM system (Double Shield Compact) was developed for the excavation of tunnels in variable rock conditions. This type of TBM was selected to excavate the 8 km long exploration tunnel in Chile for Los Bronces mine, one of the largest copper mines in the world owned by Anglo American. The 4.5 m diameter tunnel runs at an elevation of 3.600 m a.s.l. and crosses a series of geological formations of hard, compact rock crossed by several faults. The restricted area for the tunnel entrance, the climate and the required flexibility in rock support design posed the main challenges for this project.

Alcaniz P.J.R.,MBA | Gracian F.T.,Dragados
Revista de Obras Publicas | Year: 2013

The article describes the design and construction of the Arroyofresno Stormwater Deposit (the largest of its kind in Europe) and the associated pipework, a 7.40 m diameter tunnel built by EPB TBM. A description is given of the design criteria as well as the soil treatment required for the passing of the pipeline through a river, alongside various installations (in quaternary soils) and below motorways, as well as those necessary to connect the tunnel to the service wells.

Vazquez M.,Dragados | Negro V.,Technical University of Madrid | Lopez J.S.,Technical University of Madrid | Monso J.L.,Institute Hidrodinamica Aplicada INHA
Coasts, Marine Structures and Breakwaters 2013: From Sea to Shore - Meeting the Challenges of the Sea | Year: 2014

This paper presents a novel type of caisson as an integrating element in a new concept of vertical breakwater. The solution combines the advantages of cylindrical geometry with stepped wave energy dissipation, which results in a reduction of maximum wave forces, loads transmitted to foundations and a reduction in crest level in comparison with a conventional vertical breakwater. Also, substantially less materials are used. Whilst the system is complex and depends on multiple geometric, hydraulic, construction and economic variables, this article centres on its hydrodynamic aspects and summarises the most important results of a reduced model testing programme with regular wave action in the first instance, as undertaken to validate the solution in a general fashion.

Moreno-Navarro F.,University of Granada | Sol-Sanchez M.,University of Granada | Rubio-Gamez M.C.,University of Granada | Segarra-Martinez M.,Dragados
Construction and Building Materials | Year: 2014

The high stiffness provided by high modulus asphalt mixes significantly decreases the loads transmitted by the traffic to the road foundation whilst at the same time increases their resistance against plastic deformations. Thus, the use of these types of mixtures can be an effective solution in road construction, due to the fact that they can reduce the thickness of the pavement, saving economic and material resources. Nevertheless, in some cases this high stiffness constitutes a drawback because it could reduce the fatigue resistance offered by these materials, leading to a premature appearance of cracks in the pavement, which decreases its service life. Due to this fact, the use of high modulus asphalt mixes is limited, especially in cold climates. In order to solve this problem, this research has been focused on the improvement of the mechanical performance of high modulus asphalt mixtures through the use of additives (crumb rubber and acrylic fibers), which could increase their fatigue resistance by maintaining the stiffness required. Different tests have been carried out under different temperatures for the mixtures assessment. The results obtained have shown that the incorporation of these additives could lead to a better mechanical behavior of high modulus asphalt mixes, and thus it could improve their performance. © 2014 Elsevier Ltd. All rights reserved.

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