Documents disponibles écrits par cet auteur

Effect of soil conditioners on the pressure and rate-dependent shear strength of different clays / R. Zumsteg in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 9 (Septembre 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 9 (Septembre 2012) . - pp.1138–1146. Titre : Effect of soil conditioners on the pressure and rate-dependent shear strength of different clays Type de document : texte imprimé Auteurs : R. Zumsteg, Auteur ; M. Plotze, Auteur ; A. M. Puzrin, Auteur Année de publication : 2012 Article en page(s) : pp.1138–1146. Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Soil  conditioning  Clay  pastes  Vane  shear  test  Viscosity  of  clays  Clay-polymer  mixtures  Earth  pressure  balance Résumé : Tunneling using the earth pressure balance machines method in clayey soils requires the addition of conditioning chemicals to reduce the torque moment of the machine and to guarantee a safe and economical excavation process. Injection of foams and polymers at the cutter head of the tunnel boring machine with subsequent remolding in the pressure chamber transforms the excavated material into a deformable soil paste with preferably low strength and adhesion. The soil becomes more compressible and can develop viscous properties, such that the pressure and rate dependency of the shear strength of the mixtures are of major importance for the proper design and analysis of the tunneling processes. In this paper, the results of vane shear strength measurements on various conditioned clays and clay-sand mixtures at various shearing velocities and applied pressures are presented and analyzed. The results clearly show the effects of the chemicals used and also point out the differences in their efficiency depending on the clay mineralogy. This allows for an improved understanding of the working mechanisms of the chemicals. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000681 [article] Effect of soil conditioners on the pressure and rate-dependent shear strength of different clays [texte imprimé] / R. Zumsteg, Auteur ; M. Plotze, Auteur ; A. M. Puzrin, Auteur . - 2012 . - pp.1138–1146. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 9 (Septembre 2012) . - pp.1138–1146. Mots-clés : Soil  conditioning  Clay  pastes  Vane  shear  test  Viscosity  of  clays  Clay-polymer  mixtures  Earth  pressure  balance Résumé : Tunneling using the earth pressure balance machines method in clayey soils requires the addition of conditioning chemicals to reduce the torque moment of the machine and to guarantee a safe and economical excavation process. Injection of foams and polymers at the cutter head of the tunnel boring machine with subsequent remolding in the pressure chamber transforms the excavated material into a deformable soil paste with preferably low strength and adhesion. The soil becomes more compressible and can develop viscous properties, such that the pressure and rate dependency of the shear strength of the mixtures are of major importance for the proper design and analysis of the tunneling processes. In this paper, the results of vane shear strength measurements on various conditioned clays and clay-sand mixtures at various shearing velocities and applied pressures are presented and analyzed. The results clearly show the effects of the chemicals used and also point out the differences in their efficiency depending on the clay mineralogy. This allows for an improved understanding of the working mechanisms of the chemicals. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000681

Engineered use of microbial gas production to decrease primary consolidation settlement in clayey soils / A. M. Puzrin in Géotechnique, Vol. 61 N° 9 (Septembre 2011) 

Public ISBD [article]  in Géotechnique > Vol. 61 N° 9 (Septembre 2011) . - pp. 785-794 Titre : Engineered use of microbial gas production to decrease primary consolidation settlement in clayey soils Type de document : texte imprimé Auteurs : A. M. Puzrin, Auteur ; J. Tront, Auteur ; A. Schmid, Auteur Année de publication : 2011 Article en page(s) : pp. 785-794 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Consolidation  Settlement Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This feasibility study examines the use of in situ microbial gas production to engineer the consolidation properties of clayey soils by changing the settlement–time profile. A simple analytical model has been proposed to assess the swelling of the soil during the steady-state gas production, and to predict immediate settlements due to loading at the end of this process. For experimental validation of the suggested technique, Clostridium acetobutylicum, an anaerobic fermentative microorganism, was mixed into clayey-sand samples, fed with a nutrient-rich medium, and allowed to produce gas in situ. A series of standard oedometer tests was performed on gas-containing and gas-free soil specimens. Results showed that, in agreement with the model predictions, in situ gas production caused negligible swelling of the samples, while shifting a significant portion (up to 50%) of total displacement from primary consolidation settlement to immediate settlement without changing total displacements or the coefficient of consolidation. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.t.023 [article] Engineered use of microbial gas production to decrease primary consolidation settlement in clayey soils [texte imprimé] / A. M. Puzrin, Auteur ; J. Tront, Auteur ; A. Schmid, Auteur . - 2011 . - pp. 785-794. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 61 N° 9 (Septembre 2011) . - pp. 785-794 Mots-clés : Consolidation  Settlement Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This feasibility study examines the use of in situ microbial gas production to engineer the consolidation properties of clayey soils by changing the settlement–time profile. A simple analytical model has been proposed to assess the swelling of the soil during the steady-state gas production, and to predict immediate settlements due to loading at the end of this process. For experimental validation of the suggested technique, Clostridium acetobutylicum, an anaerobic fermentative microorganism, was mixed into clayey-sand samples, fed with a nutrient-rich medium, and allowed to produce gas in situ. A series of standard oedometer tests was performed on gas-containing and gas-free soil specimens. Results showed that, in agreement with the model predictions, in situ gas production caused negligible swelling of the samples, while shifting a significant portion (up to 50%) of total displacement from primary consolidation settlement to immediate settlement without changing total displacements or the coefficient of consolidation. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.t.023

Evolution of stabilised creeping landslides / A. M. Puzrin in Géotechnique, Vol. 62 N° 6 (Juin 2012) 

Public ISBD [article]  in Géotechnique > Vol. 62 N° 6 (Juin 2012) . - pp. 491–501 Titre : Evolution of stabilised creeping landslides Type de document : texte imprimé Auteurs : A. M. Puzrin, Auteur ; A. Schmid, Auteur Année de publication : 2012 Article en page(s) : pp. 491–501 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Creep  Soil  stabilisation  Landslides  Case  history Résumé : A simple analytical model is proposed to quantify evolution of a creeping landslide stabilised by a retaining wall, or by a natural barrier at the bottom of the sliding mass. Development in time of both the landslide displacements and the earth pressure acting on the retaining structure is obtained in the closed form, with the latter given by the classical Terzaghi expression for the average degree of consolidation. Depending on the value of the long-term safety factor, the landslide either eventually slows down, asymptotically approaching final displacements, or the soil behind the retaining wall comes to a passive failure, followed by a post-failure evolution of the landslide. The model is capable of quantifying both scenarios, with some of its features successfully validated against the monitoring and geotechnical data from the two case studies: the Combe Chopin and Ganter landslides in Switzerland. For the Combe Chopin landslide, which came to a standstill, the model has demonstrated its ability to predict final downhill displacements and their development in time. For the Ganter landslide, which failed and achieved steady-state velocity, the model correctly predicted the long-term landslide evolution and the effects of drainage and erosion on the displacement rates. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.11.P.041 [article] Evolution of stabilised creeping landslides [texte imprimé] / A. M. Puzrin, Auteur ; A. Schmid, Auteur . - 2012 . - pp. 491–501. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 62 N° 6 (Juin 2012) . - pp. 491–501 Mots-clés : Creep  Soil  stabilisation  Landslides  Case  history Résumé : A simple analytical model is proposed to quantify evolution of a creeping landslide stabilised by a retaining wall, or by a natural barrier at the bottom of the sliding mass. Development in time of both the landslide displacements and the earth pressure acting on the retaining structure is obtained in the closed form, with the latter given by the classical Terzaghi expression for the average degree of consolidation. Depending on the value of the long-term safety factor, the landslide either eventually slows down, asymptotically approaching final displacements, or the soil behind the retaining wall comes to a passive failure, followed by a post-failure evolution of the landslide. The model is capable of quantifying both scenarios, with some of its features successfully validated against the monitoring and geotechnical data from the two case studies: the Combe Chopin and Ganter landslides in Switzerland. For the Combe Chopin landslide, which came to a standstill, the model has demonstrated its ability to predict final downhill displacements and their development in time. For the Ganter landslide, which failed and achieved steady-state velocity, the model correctly predicted the long-term landslide evolution and the effects of drainage and erosion on the displacement rates. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.11.P.041

Simple approach to predicting ground displacements caused by tunnelling in undrained anisotropic elastic soil / A. M. Puzrin in Géotechnique, Vol. 62 N° 4 (Avril 2012) 

Public ISBD [article]  in Géotechnique > Vol. 62 N° 4 (Avril 2012) . - pp. 341–352 Titre : Simple approach to predicting ground displacements caused by tunnelling in undrained anisotropic elastic soil Type de document : texte imprimé Auteurs : A. M. Puzrin, Auteur ; J. B. Burland, Auteur ; J.R. Standing, Auteur Année de publication : 2012 Article en page(s) : pp. 341–352 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Anisotrop  Settlement  Tunnels Résumé : An attempt to develop a kinematically based approach to predicting ground settlements due to tunnelling is represented, by using the more reliable data of the commonly observed settlement troughs, rather than imposing the boundary conditions on the tunnel surface, which have a high level of uncertainty. The anisotropic elastic model used in this work is highly simplified, and the resulting analytical solution is of an approximate nature. Nevertheless, it seems to provide good agreement with both the shape and the magnitude of the observed settlement trough. Based on this solution, a modification is proposed for the widely used empirical Gaussian curve, by correlating the trough width parameter K with the ratio between the two anisotropic shear moduli, G hh/G vh. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/issue/geot/62/4# [article] Simple approach to predicting ground displacements caused by tunnelling in undrained anisotropic elastic soil [texte imprimé] / A. M. Puzrin, Auteur ; J. B. Burland, Auteur ; J.R. Standing, Auteur . - 2012 . - pp. 341–352. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 62 N° 4 (Avril 2012) . - pp. 341–352 Mots-clés : Anisotrop  Settlement  Tunnels Résumé : An attempt to develop a kinematically based approach to predicting ground settlements due to tunnelling is represented, by using the more reliable data of the commonly observed settlement troughs, rather than imposing the boundary conditions on the tunnel surface, which have a high level of uncertainty. The anisotropic elastic model used in this work is highly simplified, and the resulting analytical solution is of an approximate nature. Nevertheless, it seems to provide good agreement with both the shape and the magnitude of the observed settlement trough. Based on this solution, a modification is proposed for the widely used empirical Gaussian curve, by correlating the trough width parameter K with the ratio between the two anisotropic shear moduli, G hh/G vh. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/issue/geot/62/4#