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Geomechanics and Engineering
  Volume 8, Number 2, February 2015 , pages 153-171
DOI: https://doi.org/10.12989/gae.2015.8.2.153
 


Methodology for real-time adaptation of tunnels support using the observational method
Tiago Miranda, Daniel Dias, Marisa Pinheiro and St&$233;phanie Eclaircy-Caudron

 
Abstract
    The observational method in tunnel engineering allows the evaluation in real time of the actual conditions of the ground and to take measures if its behavior deviates considerably from predictions. However, it lacks a consistent and structured methodology to use the monitoring data to adapt the support system in real time. The definition of limit criteria above which adaptation is required are not defined and complex inverse analysis procedures (Rechea et al. 2008, Levasseur et al. 2010, Zentar et al. 2001, Lecampion et al. 2002, Finno and Calvello 2005, Goh 1999, Cui and Pan 2012, Deng et al. 2010, Mathew and Lehane 2013, Sharifzadeh et al. 2012, 2013) may be needed to consistently analyze the problem. In this paper a methodology for the real time adaptation of the support systems during tunneling is presented. In a first step limit criteria for displacements and stresses are proposed. The methodology uses graphics that are constructed during the project stage based on parametric calculations to assist in the process and when these graphics are not available, since it is not possible to predict every possible scenario, inverse analysis calculations are carried out. The methodology is applied to the "Bois de Peu" tunnel which is composed by two tubes with over 500 m long. High uncertainty levels existed concerning the heterogeneity of the soil and consequently in the geomechanical design parameters. The methodology was applied in four sections and the results focus on two of them. It is shown that the methodology has potential to be applied in real cases contributing for a consistent approach of a real time adaptation of the support system and highlight the importance of the existence of good quality and specific monitoring data to improve the inverse analysis procedure.
 
Key Words
    tunnel; observational method; inverse analysis; numerical modeling
 
Address
(1) Tiago Miranda, Marisa Pinheiro:
ISISE, University of Minho, Department of Civil Engineering, Campus de Azurém 4800-058 Guimarães, Portugal;
(2) Daniel Dias:
Grenoble Alpes University, 3SR, UMR 5521, 38041 Grenoble Cedex 9, France;
(3) St&$233;phanie Eclaircy-Caudron:
EDF, Division RTE, Lyon, France.
 

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