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Sant'Ambrogio di Torino, Italy

Sterpi D.,Polytechnic of Milan | Rizzo F.,GEODATA Engineering SpA | Renda D.,ANAS S.p.A | Aguglia F.,Impresa Pizzarotti and C. S.p.A. | Zenti C.L.,Elas Geotecnica S.r.l.
Tunnelling and Underground Space Technology | Year: 2013

In presence of difficult conditions in tunnelling, an adequate stabilization of the excavation boundary and face is required to ensure a safe progress of the construction. The stabilization of the tunnel face can be improved by fibreglass soil nailing, offering properties optimal to the purpose and versatility in use. This paper reports a tunnelling experience where difficult conditions, induced by poor mechanical properties of the rock mass and relevant pore water pressures, were faced adopting innovative soil nailing techniques. Some details about the site geological conditions allow to recognize the causes of the difficult conditions which drove towards specific choices about the features of soil nails, acting on both aspects of mechanical reinforcement and drainage. The soil nail mechanical contribution to the tunnel face stabilization is taken into account at the design stage by an equivalent increase of effective cohesion in the improved ground mass. The tunnel face stability is then assessed by analytical approach. The performance and the specific advantages of the innovative technique are discussed also on the basis of results from on site testing. © 2013 Elsevier Ltd. Source

Dematteis A.,GEODATA Engineering SpA | Soldo L.,GEODATA Engineering SpA
Georisk | Year: 2015

In this paper recent improvements of the R-Index method are presented, based on its application on several projects in various geological and geotechnical contexts. The R-Index derives from a probabilistic procedure conceived for estimating the reliability level of the Geological and Geotechnical Design Model used to design underground structures, especially tunnels. The R-Index takes into account the geological complexity of a site and recommended empirical scores (based on expert judgement) for different quality levels of geological surveys and geotechnical and geophysical investigations. © 2015 Geodata Engineering S.p.A. Source

Logarzo A.,University of Rome La Sapienza | Miliziano S.,University of Rome La Sapienza | Floria V.,GEODATA Engineering SpA | Pescara M.,GEODATA Engineering SpA
Geotechnical Aspects of Underground Construction in Soft Ground - Proceedings of the 7th International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground | Year: 2012

The paper deals with the main results of 3D numerical analyses carried out in order to simulate the tunnel construction for the real case of "Túneles aliviadores del emisario principal del arroyo Maldonado" in Buenos Aires. Full 3D numerical analyses are also developed to study the interaction between tunneling excavation and a tall concrete building. The numerical models take into account the main features of excavation process with Tunnel Boring Machine (presence of shield, face pressure, tail void grout injection); a realistic structural model of the building is also used. Due to the very small level of deformation expected, a simply elastic perfectly plastic with Mohr Coulomb strength criterion is adopted; values of stiffness parameters are selected at very small deformation level. Soil parameters were determined by means of in situ and in lab experimental test results. Comparison between the monitoring data and numerical results shows the good forecast capacity of the geotechnical model developed and encourages utilizing of 3D analysis as a valuable tool in tunnel design in urban areas. © 2012 Taylor & Francis Group. Source

Carrieri G.,GEODATA Engineering SpA | Poli A.,GEODATA Engineering SpA | Repetto L.,GEODATA Engineering SpA
Underground - The Way to the Future: Proceedings of the World Tunnel Congress, WTC 2013 | Year: 2013

The Udhampur-Srinagar-Baramulla Rail Link (USBRL) Project, among the most important infrastructure projects in India, will connect the Kashmir valley to the national transportation network. The T-74R Tunnel lays along the Udhampur-Qazigund section, which features the most complex geology in the USBRL. Having encountered severe difficulties during excavation of T-67, T-68, T-73 and T-74 tunnels (rock masses with poor geomechanical properties, related to landslides and fault zones) a new long and deep tunnel was proposed: the T-74R (L=8.6 km). In order to select the general tunnel layout, a Multi Criteria Analysis (MCA) has been applied and four alternative solutions (all with an intermediate adit) were investigated: 1) and 2) single tube - single track (with and without motorable escape way); 3) single tube - single track plus a parallel escape tunnel; 4) twin tube - single track. Taking into account construction and safety aspects as along with construction costs, the MCA results have shown the single tube - single track tunnel with a parallel escape tunnel is the best option. The construction of this tunnel started in the beginning of 2012. This paper describes the process of selecting the tunnel cross section and layout, the design criteria and the main characteristics of the T-74R tunnel, highlighting the typical sections of primary support to be applied along the whole tunnel. © 2013 Taylor & Francis Group. Source

Gaspari G.M.,GEODATA Engineering SpA | Quaglio G.,GEODATA Engineering SpA | Floria V.,GEODATA Engineering SpA
Geotechnical Aspects of Underground Construction in Soft Ground - Proceedings of the 7th International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground | Year: 2012

Historically, underground facilities have experienced a lower rate of damage than surface structures. Nevertheless, some underground structures registered significant damages in recent large earthquakes; the resultant database which can be found in literature, together with the quite slight overburden of many stretches of the Istanbul new metro line, required a particular care on the verification of the vulnerability of the underground structures under severe seismic events. This article describes briefly the main assessments on the approaches used by engineers in quantifying the seismic effect on an underground structure, both referring to deterministic either probabilistic methods. However, this study has the goal to propose a method that could be as more consistent as possible with the common procedures nowadays adopted to evaluate the effect of seismic motion on tunnels. In particular, as the complex geometry of most of the cross sections in Istanbul Metro underground structures is not simple enough to make proper use of the closed form solutions, a numerical method is recognized as the only one to assist the design process. However, a simple yet rational method of analysis for evaluating the ovaling effect was preferred than a complete coupled analysis, with an application of the time dependent acceleration spectrum, because the large number of different structures and geological conditions required to optimize the time cost of the procedure. © 2012 Taylor & Francis Group. Source

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