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Modeling ground-Ssell contact forces in NATM tunneling based on three-dimensional displacement measurements / Shafi Ullah in Journal of geotechnical and geoenvironmental engineering, Vol. 139 N° 3 (Mars 2013) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 444–457 Titre : Modeling ground-Ssell contact forces in NATM tunneling based on three-dimensional displacement measurements Type de document : texte imprimé Auteurs : Shafi Ullah, Auteur ; Bernhard Pichler, Auteur ; Christian Hellmich, Auteur Année de publication : 2013 Article en page(s) : pp. 444–457 Note générale : geotechnique Langues : Anglais (eng) Mots-clés : monitoring;  displacement;  micromechanics;  hydration;  measurement;  tunneling;  creep Résumé : Based on an advanced micromechanics-based nonlinear creep model for shotcrete and thin shell kinematics, measured displacement data are first converted into in-plane stress fields throughout a shotcrete tunnel shell driven according to the New Austrian Tunneling Method (NATM). Subsequently, the partial differential equations for the local force equilibrium in the cylindrical coordinate directions are solved for out-of-plane shell stresses, inclusive of the tractions at the ground-shell interface. Results obtained for an NATM-tunnel driven through clayey ground at moderate depth show that the maximum shear tractions at the ground-shell interface may even exceed the maximum normal tractions (ground pressure). At the same time, even a young top heading tunnel shell may act as an arching thrust. The authors regard this method as a further step in the continously refined of interpretation of displacement measurements stemming from tunnel monitoring systems for the NATM, on a well-defined mechanical basis. This results in two structural models for top heading excavation stages, which might have the potential to support NATM predesign activities in the future. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000791 [article] Modeling ground-Ssell contact forces in NATM tunneling based on three-dimensional displacement measurements [texte imprimé] / Shafi Ullah, Auteur ; Bernhard Pichler, Auteur ; Christian Hellmich, Auteur . - 2013 . - pp. 444–457. geotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 444–457 Mots-clés : monitoring;  displacement;  micromechanics;  hydration;  measurement;  tunneling;  creep Résumé : Based on an advanced micromechanics-based nonlinear creep model for shotcrete and thin shell kinematics, measured displacement data are first converted into in-plane stress fields throughout a shotcrete tunnel shell driven according to the New Austrian Tunneling Method (NATM). Subsequently, the partial differential equations for the local force equilibrium in the cylindrical coordinate directions are solved for out-of-plane shell stresses, inclusive of the tractions at the ground-shell interface. Results obtained for an NATM-tunnel driven through clayey ground at moderate depth show that the maximum shear tractions at the ground-shell interface may even exceed the maximum normal tractions (ground pressure). At the same time, even a young top heading tunnel shell may act as an arching thrust. The authors regard this method as a further step in the continously refined of interpretation of displacement measurements stemming from tunnel monitoring systems for the NATM, on a well-defined mechanical basis. This results in two structural models for top heading excavation stages, which might have the potential to support NATM predesign activities in the future. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000791