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Tran-Manh H.,ParisTech National School of Bridges and Roads | Sulem J.,ParisTech National School of Bridges and Roads | Subrin D.,Center dEtudes des Tunnels
Acta Geotechnica | Year: 2016

Time-dependent response of deep tunnels is studied considering the progressive degradation of the mechanical properties of the rock mass. The constitutive model is based on a rock-aging law for the uniaxial strength of the rock and for the Young’s modulus. A semi-analytical solution is developed for the stresses and displacements around a deep circular tunnel taking into account the face advance. The evolution of the plastic and damage zones over time is determined. Numerical examples are presented for the case of Saint-Martin-La-Porte access adit in France of the Lyon–Turin Base Tunnel. The computed results which are compared with the field data in terms of the convergence of tunnel wall and of the displacements inside the rock mass monitored by multi-point extensometers show the efficiency of the approach to simulate the time-dependent deformation of a tunnel excavated in squeezing ground. Simple relationships are proposed to evaluate the parameters of the constitutive model directly from those of the empirical convergence law presented in previous work. © 2016 Springer-Verlag Berlin Heidelberg

Kashef A.,National Research Council Canada | Viegas J.,National Laboratory for Civil Engineering | Mos A.,Center dEtudes des Tunnels | Harvey N.,Parsons Brinckerhoff
ASHRAE Transactions | Year: 2012

Design fires are an intrinsic part in designing tunnels for fires. They provide, quantitatively, the fire characteristics that are used to establish the sizing of equipment in tunnels and the scenarios to consider when developing emergency response plans. They are also used, indirectly, when considering the impact of fires on the structure. As such, design fires form the base input for emergency ventilation, evacuation, and structural design analyses. A design fire is generally defined in terms of heat release rate, and species output as functions of time. This paper summarizes efforts to develop a set of design fire curves as a useful tool for road tunnel fire risk assessment. The developed design fire curves include the following phases: (1) incubation phase, (2) growth phase, (3) fully-developed phase, and (4) decay phase. © 2012 ASHRAE.

Berthoz N.,Center Detudes Techniques Of Lequipement Mediterranee | Branque D.,National School of Public Civil Engineering | Wong H.,National School of Public Civil Engineering | Subrin D.,Center dEtudes des Tunnels
Canadian Geotechnical Journal | Year: 2013

The capacity of a commercially available miniature pressure sensor for measuring stress evolutions in a partially saturated soil under quasi-static loads is studied, in view of its later application in laboratory-scale physical models. An extensive calibration program is first performed on a triaxial cell under isotropic loadings. These calibration tests provide useful data for assessing the uncertainty in stress measurements, especially in the case of partially saturated granular materials. Notably, influences of soil density, water content, and average grain size on stress measurements are quantified. Following these tests, an example of stress measurements on an original reduced-scale model of "earth pressure balance shield" (EPBS) is presented, which involves three-dimensional arching effects developing around the shield during excavation.

Tailhan J.-L.,Laboratoire Central des Ponts et Chaussees | D'Aloia L.,Center dEtudes des Tunnels | Autuori P.,Bouygues Travaux Publics
Bulletin des Laboratoires des Ponts et Chaussees | Year: 2010

An effective control over early-age behavior in concrete serves to guarantee successful applications on civil engineering project sites. Numerical tools designed to assist decision-making during the critical phases of concrete structure design and execution are indeed available. This document provides a summary presentation of a simple numerical simulation model of the thermomechanical behavior of early-age concrete; it offers insight into both the temperature and stress fields that develop as of the first few hours of concreting within structures and moreover enables conducting a cracking risk analysis. An industrial application example using this tool is also proposed herein.

Taillefer N.,French Scientific and Technical Center for Building | Carlotti P.,French Scientific and Technical Center for Building | Larive C.,Center dEtudes des Tunnels | Lemerle C.,French Scientific and Technical Center for Building | And 2 more authors.
Fire Technology | Year: 2013

This paper recalls the genesis of the increased hydrocarbon temperature curve (HCinc) 10 years after its introduction in France. The statutory context, the role of the HCinc curve and the main issues raised are described. In the second section, results from fire resistance tests on concrete slabs exposed to the temperature curve in the framework of experimental research programs are presented and discussed. They are supplemented by a summary of a large number of commercial tests. An original test protocol allowing subjecting the slabs heated surface in compression is described. In the last section, current trends for fire resistance design in France are given. Assessment methodology for new and existing tunnels based on experiments and simulation are described. Recommendations are finally given in the utilization of passive protections. © 2012 Springer Science+Business Media, LLC.

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