Documents disponibles écrits par cet auteur

Analysis of extensible reinforcement subject to oblique pull / J. T. Shahu in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 5 (Mai 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 5 (Mai 2009) . - pp. 623–634 Titre : Analysis of extensible reinforcement subject to oblique pull Type de document : texte imprimé Auteurs : J. T. Shahu, Auteur ; S. Hayashi, Auteur Année de publication : 2009 Article en page(s) : pp. 623–634 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Geosynthetics  Pull-out  resistance  Failure  Subgrades  Finite  element  method Résumé : A rational analysis of extensible sheet reinforcement subjected to an oblique end force has been presented that properly accounts for complex soil-reinforcement interaction and involves stress-deformation relationship implicitly. The results can be used for internal design of geosynthetic reinforced soil walls against pullout failure and tension failure. The pullout force and the end displacement at pullout for an extensible reinforcement are found to be almost the same as those for an inextensible reinforcement if the ratio of the reinforcement stiffness to the axial pullout capacity J∗ is greater than 15. With decrease in J∗ below 15, the maximum strain increases, the pullout failure becomes irrelevant, the tension failure dominates and the maximum allowable oblique force decreases. A minimum stiffness of about 25 times the axial pullout capacity is required to avoid the tension failure before the pullout provided the failure strain is 0.1. The predicted results have been calibrated against the finite-element analysis of pullout tests and detailed back analyses of published test data on model reinforced walls constructed with a wide range of extensible materials. The present analysis gives better predictions of the critical height against the pullout and the tension failure in model reinforced soil walls constructed with extensible reinforcements as compared to that of Rankine’s method. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000019 [article] Analysis of extensible reinforcement subject to oblique pull [texte imprimé] / J. T. Shahu, Auteur ; S. Hayashi, Auteur . - 2009 . - pp. 623–634. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 5 (Mai 2009) . - pp. 623–634 Mots-clés : Geosynthetics  Pull-out  resistance  Failure  Subgrades  Finite  element  method Résumé : A rational analysis of extensible sheet reinforcement subjected to an oblique end force has been presented that properly accounts for complex soil-reinforcement interaction and involves stress-deformation relationship implicitly. The results can be used for internal design of geosynthetic reinforced soil walls against pullout failure and tension failure. The pullout force and the end displacement at pullout for an extensible reinforcement are found to be almost the same as those for an inextensible reinforcement if the ratio of the reinforcement stiffness to the axial pullout capacity J∗ is greater than 15. With decrease in J∗ below 15, the maximum strain increases, the pullout failure becomes irrelevant, the tension failure dominates and the maximum allowable oblique force decreases. A minimum stiffness of about 25 times the axial pullout capacity is required to avoid the tension failure before the pullout provided the failure strain is 0.1. The predicted results have been calibrated against the finite-element analysis of pullout tests and detailed back analyses of published test data on model reinforced walls constructed with a wide range of extensible materials. The present analysis gives better predictions of the critical height against the pullout and the tension failure in model reinforced soil walls constructed with extensible reinforcements as compared to that of Rankine’s method. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000019

Clayey soil reinforced with stone column group / J. T. Shahu in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 12 (Décembre 2011) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 12 (Décembre 2011) . - pp. 1265-1274 Titre : Clayey soil reinforced with stone column group : Model tests and analyses Type de document : texte imprimé Auteurs : J. T. Shahu, Auteur ; Y. R. Reddy, Auteur Année de publication : 2012 Article en page(s) : pp. 1265-1274 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Stone  columns  Clayey  soil  Foundation  Model  tests  Finite-element  analysis Résumé : Fully drained, load-controlled laboratory model tests and their numerical simulations are presented. The tests were performed on adequately instrumented, small scale physical models of floating stone column group foundations placed in slurry deposited clayey soil beds with known effective stress states. Effect of various group foundation parameters, such as area ratio, length of columns, relative density, and moisture content of the column material is evaluated. The numerical analyses consist of three-dimensional, elastoplastic, finite-element analyses of the model foundation. In the analyses, the clayey soil behavior is represented by the modified Cam-clay model, and the stone column and mat are represented by the elastic, fully plastic Mohr-Coulomb constitutive relationship. The finite-element analysis was successful in predicting the model test results with reasonable accuracy. The results are presented in nondimensional form. The major foundation parameters affecting the group response were identified as area ratio, normalized column length, Young’s modulus of column, overconsolidation ratio, initial geostatic stresses, and clayey soil parameters. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i12/p1265_s1?isAuthorized=no [article] Clayey soil reinforced with stone column group : Model tests and analyses [texte imprimé] / J. T. Shahu, Auteur ; Y. R. Reddy, Auteur . - 2012 . - pp. 1265-1274. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 12 (Décembre 2011) . - pp. 1265-1274 Mots-clés : Stone  columns  Clayey  soil  Foundation  Model  tests  Finite-element  analysis Résumé : Fully drained, load-controlled laboratory model tests and their numerical simulations are presented. The tests were performed on adequately instrumented, small scale physical models of floating stone column group foundations placed in slurry deposited clayey soil beds with known effective stress states. Effect of various group foundation parameters, such as area ratio, length of columns, relative density, and moisture content of the column material is evaluated. The numerical analyses consist of three-dimensional, elastoplastic, finite-element analyses of the model foundation. In the analyses, the clayey soil behavior is represented by the modified Cam-clay model, and the stone column and mat are represented by the elastic, fully plastic Mohr-Coulomb constitutive relationship. The finite-element analysis was successful in predicting the model test results with reasonable accuracy. The results are presented in nondimensional form. The major foundation parameters affecting the group response were identified as area ratio, normalized column length, Young’s modulus of column, overconsolidation ratio, initial geostatic stresses, and clayey soil parameters. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i12/p1265_s1?isAuthorized=no

Pasternak model for oblique pullout of inextensible reinforcement / Shantanu Patra in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 12 (Décembre 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 12 (Décembre 2012) . - pp. 1503–1513 Titre : Pasternak model for oblique pullout of inextensible reinforcement Type de document : texte imprimé Auteurs : Shantanu Patra, Auteur ; J. T. Shahu, Auteur Année de publication : 2013 Article en page(s) : pp. 1503–1513 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Reinforced  soil  structures  Pullout  analysis  Subgrade  soil  Pasternak  model  Model  tests  Finite-difference  method Résumé : An analysis is presented for evaluation of the pullout capacity of sheet reinforcement subjected to oblique pullout force considering that the subgrade soil is represented as a two-parameter linear-elastic Pasternak model and the reinforcement as inextensible. Use of the Pasternak model makes the oblique pullout analysis more realistic. The orientation of the reinforcement at the pullout end is found to be different from the direction of the pullout force and depends on the shear modulus of the subgrade soil. A parametric study is carried out to evaluate the effect of various factors, such as the modulus of the subgrade reaction, shear modulus of the subgrade, angle of interface shear resistance, and the obliquity of the pullout force on the magnitude and direction of the reinforcement force and the end displacement. For the first time, oblique pullout results have been compared with direct measurements of the reinforcement inclination in the vicinity of the failure surface available in the literature, and the experimental data compare well with the present analysis. Model tests on single and multiple sections of sheet and strip reinforcements are also performed to study the suitability and applicability of the present analysis in the design of reinforced soil walls. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000720 [article] Pasternak model for oblique pullout of inextensible reinforcement [texte imprimé] / Shantanu Patra, Auteur ; J. T. Shahu, Auteur . - 2013 . - pp. 1503–1513. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 12 (Décembre 2012) . - pp. 1503–1513 Mots-clés : Reinforced  soil  structures  Pullout  analysis  Subgrade  soil  Pasternak  model  Model  tests  Finite-difference  method Résumé : An analysis is presented for evaluation of the pullout capacity of sheet reinforcement subjected to oblique pullout force considering that the subgrade soil is represented as a two-parameter linear-elastic Pasternak model and the reinforcement as inextensible. Use of the Pasternak model makes the oblique pullout analysis more realistic. The orientation of the reinforcement at the pullout end is found to be different from the direction of the pullout force and depends on the shear modulus of the subgrade soil. A parametric study is carried out to evaluate the effect of various factors, such as the modulus of the subgrade reaction, shear modulus of the subgrade, angle of interface shear resistance, and the obliquity of the pullout force on the magnitude and direction of the reinforcement force and the end displacement. For the first time, oblique pullout results have been compared with direct measurements of the reinforcement inclination in the vicinity of the failure surface available in the literature, and the experimental data compare well with the present analysis. Model tests on single and multiple sections of sheet and strip reinforcements are also performed to study the suitability and applicability of the present analysis in the design of reinforced soil walls. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000720