Documents disponibles écrits par cet auteur

Experimental and modeling studies of permanent strains of subgrade soils / Anand J. Puppala in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 10 (Octobre 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 10 (Octobre 2009) . - pp. 1379–1389 Titre : Experimental and modeling studies of permanent strains of subgrade soils Type de document : texte imprimé Auteurs : Anand J. Puppala, Auteur ; Sireesh Saride, Auteur ; Suppakit Chomtid, Auteur Année de publication : 2009 Article en page(s) : pp. 1379–1389 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : StrainSubgradesModelsRepeated  loadTriaxial  testsExperimentation Résumé : Mechanistic-empirical pavement design guide for flexible pavements as per the AASHTO design guide requires characterization of subgrade soils using the resilient modulus (MR) property. This property, however, does not fully account for the plastic or permanent strain or rutting of subgrade soils, which often distress the overlying pavements. Soils such as silts exhibit moderate to high resilient moduli properties but they still undergo large permanent deformations under repeated loading. This explains the fallacy in the current pavement material characterization practice. A comprehensive research study was performed to measure permanent deformation properties of subgrade soils by subjecting various soils under repeated cycles of deviatoric loads. This paper describes test procedure followed and results obtained on three soils including clay, silt, and sandy soils. The influence of compaction moisture content, confining pressure, and deviatoric stresses applied on the measured permanent deformations of all three soils are addressed. A four-parameter permanent strain model formulation as a function of stress states in soils and the number of loading cycles was used to model and analyze the present test results. The model constants of all three soils were first determined and these results were used to explain the effects of various soil properties on permanent deformations of soils. Validation studies were performed to address the adequacy of the formulated model to predict rutting or permanent strains in soils. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000163 [article] Experimental and modeling studies of permanent strains of subgrade soils [texte imprimé] / Anand J. Puppala, Auteur ; Sireesh Saride, Auteur ; Suppakit Chomtid, Auteur . - 2009 . - pp. 1379–1389. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 10 (Octobre 2009) . - pp. 1379–1389 Mots-clés : StrainSubgradesModelsRepeated  loadTriaxial  testsExperimentation Résumé : Mechanistic-empirical pavement design guide for flexible pavements as per the AASHTO design guide requires characterization of subgrade soils using the resilient modulus (MR) property. This property, however, does not fully account for the plastic or permanent strain or rutting of subgrade soils, which often distress the overlying pavements. Soils such as silts exhibit moderate to high resilient moduli properties but they still undergo large permanent deformations under repeated loading. This explains the fallacy in the current pavement material characterization practice. A comprehensive research study was performed to measure permanent deformation properties of subgrade soils by subjecting various soils under repeated cycles of deviatoric loads. This paper describes test procedure followed and results obtained on three soils including clay, silt, and sandy soils. The influence of compaction moisture content, confining pressure, and deviatoric stresses applied on the measured permanent deformations of all three soils are addressed. A four-parameter permanent strain model formulation as a function of stress states in soils and the number of loading cycles was used to model and analyze the present test results. The model constants of all three soils were first determined and these results were used to explain the effects of various soil properties on permanent deformations of soils. Validation studies were performed to address the adequacy of the formulated model to predict rutting or permanent strains in soils. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000163

Quality assessment and quality control of deep soil mixing construction for stabilizing expansive subsoils / Raja Sekhar Madhyannapu in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 1 (Janvier 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 119-128 Titre : Quality assessment and quality control of deep soil mixing construction for stabilizing expansive subsoils Type de document : texte imprimé Auteurs : Raja Sekhar Madhyannapu, Auteur ; Anand J. Puppala, Auteur ; Soheil Nazarian, Auteur Article en page(s) : pp. 119-128 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Expansive  soils  Lime  Cement  Soil  mixing  Shear  modulus  Nondestructive  tests Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents the process and results of a quality management program performed during and immediately after the construction of two deep soil mixing (DSM) test sections. The quality management program consisted of laboratory, in situ, and mineralogical tests to address the effectiveness of the treatment during and after construction. In situ investigations including the down-hole seismic and spectral analysis of surface waves (SASW) test methods were performed to evaluate the degree of improvement achieved through the measurement of compression and shear-wave velocities of the columns and surrounding soils. Scanning electron microscopy and electron dispersive x-ray analysis were performed on raw, laboratory treated and field-treated specimens for qualitative understanding of the degree of mixing achieved in the field and the compounds formed at particle level during stabilization, respectively. Laboratory tests results on field cores indicated that both field stiffness and strength are about 20 to 40% less than the corresponding laboratory prepared soil samples. The down-hole seismic and SASW tests showed considerable improvement in stiffness in and around the DSM columns. Mineralogical studies indicated the formation of silica and alumina hydrates along with interwoven structure of lime-cement treated clay particles in both laboratory and field specimens, suggesting adequate mixing of the soil and binder in both environments. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&smode=strres [...] [article] Quality assessment and quality control of deep soil mixing construction for stabilizing expansive subsoils [texte imprimé] / Raja Sekhar Madhyannapu, Auteur ; Anand J. Puppala, Auteur ; Soheil Nazarian, Auteur . - pp. 119-128. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 119-128 Mots-clés : Expansive  soils  Lime  Cement  Soil  mixing  Shear  modulus  Nondestructive  tests Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents the process and results of a quality management program performed during and immediately after the construction of two deep soil mixing (DSM) test sections. The quality management program consisted of laboratory, in situ, and mineralogical tests to address the effectiveness of the treatment during and after construction. In situ investigations including the down-hole seismic and spectral analysis of surface waves (SASW) test methods were performed to evaluate the degree of improvement achieved through the measurement of compression and shear-wave velocities of the columns and surrounding soils. Scanning electron microscopy and electron dispersive x-ray analysis were performed on raw, laboratory treated and field-treated specimens for qualitative understanding of the degree of mixing achieved in the field and the compounds formed at particle level during stabilization, respectively. Laboratory tests results on field cores indicated that both field stiffness and strength are about 20 to 40% less than the corresponding laboratory prepared soil samples. The down-hole seismic and SASW tests showed considerable improvement in stiffness in and around the DSM columns. Mineralogical studies indicated the formation of silica and alumina hydrates along with interwoven structure of lime-cement treated clay particles in both laboratory and field specimens, suggesting adequate mixing of the soil and binder in both environments. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&smode=strres [...]

Quantitative estimation of clay mineralogy in fine-grained soils / Bhaskar Chittoori in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 11 (Novembre 2011) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 997-1008 Titre : Quantitative estimation of clay mineralogy in fine-grained soils Type de document : texte imprimé Auteurs : Bhaskar Chittoori, Auteur ; Anand J. Puppala, Auteur Année de publication : 2012 Article en page(s) : pp. 997-1008 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Clay  mineralogy  Montmorillonite  Kaolinite  Expansive  soil  Mineral  quantification  Artificial  neural  networks Résumé : Stabilization design guidelines based on soil plasticity properties have certain limitations. Soils of similar plasticity properties can contain different dominant clay minerals, and hence, their engineering behavior can be different when stabilized with the same chemical additive and dosage. It is essential to modify stabilizer design guidelines by including clay mineralogy of the soil and its interactions with chemical additives used. Chemical properties of a soil including cation exchange capacity (CEC), specific surface area (SSA) and total potassium (TP) are dependent on clay mineral constituents, and an attempt is made in this study to develop a rational and practical methodology to determine both clay mineralogy distribution and dominant clay mineral in a soil by using three measured chemical soil properties and their analyses. This approach has been evaluated by determining and evaluating clay minerals present in artificial and natural clayey soils of known and unknown clay mineralogy. A total of twenty natural and six artificial soils were considered and used in the chemical analyses. Test results and subsequent analyses including the development of artificial neural network (ANN) based models are evaluated and described in this paper. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p997_s1?isAuthorized=no [article] Quantitative estimation of clay mineralogy in fine-grained soils [texte imprimé] / Bhaskar Chittoori, Auteur ; Anand J. Puppala, Auteur . - 2012 . - pp. 997-1008. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 997-1008 Mots-clés : Clay  mineralogy  Montmorillonite  Kaolinite  Expansive  soil  Mineral  quantification  Artificial  neural  networks Résumé : Stabilization design guidelines based on soil plasticity properties have certain limitations. Soils of similar plasticity properties can contain different dominant clay minerals, and hence, their engineering behavior can be different when stabilized with the same chemical additive and dosage. It is essential to modify stabilizer design guidelines by including clay mineralogy of the soil and its interactions with chemical additives used. Chemical properties of a soil including cation exchange capacity (CEC), specific surface area (SSA) and total potassium (TP) are dependent on clay mineral constituents, and an attempt is made in this study to develop a rational and practical methodology to determine both clay mineralogy distribution and dominant clay mineral in a soil by using three measured chemical soil properties and their analyses. This approach has been evaluated by determining and evaluating clay minerals present in artificial and natural clayey soils of known and unknown clay mineralogy. A total of twenty natural and six artificial soils were considered and used in the chemical analyses. Test results and subsequent analyses including the development of artificial neural network (ANN) based models are evaluated and described in this paper. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p997_s1?isAuthorized=no

Semi-empirical model for the prediction of modulus of elasticity for unsaturated soils / Won Taek Oh in Canadian geotechnical journal, Vol. 46 N° 8 (Août 2009) 

Public ISBD [article]  in Canadian geotechnical journal > Vol. 46 N° 8 (Août 2009) . - pp. 903-914 Titre : Semi-empirical model for the prediction of modulus of elasticity for unsaturated soils Type de document : texte imprimé Auteurs : Won Taek Oh, Auteur ; Sai K. Vanapalli, Auteur ; Anand J. Puppala, Auteur Article en page(s) : pp. 903-914 Note générale : Sciences de la Terre Langues : Anglais (eng) Mots-clés : Modulus  of  elasticity  Soil-water  characteristic  curve  Elastic  settlement  Matric  suction  Model  footing  tests  Module  d’élasticité  Courbe  de  rétention  d’eau  Tassement  Succion  matricielle  Essais  sur  semelles  modèles Index. décimale : 550 Sciences auxiliaires de la géologie. Résumé : A semi-empirical model is proposed in this paper to predict the variation of modulus of elasticity with respect to matric suction for unsaturated sandy soils using the soil-water characteristic curve (SWCC) and the modulus of elasticity under saturated conditions. Using this model, comparisons are provided between the predicted and measured moduli of elasticity and elastic settlements from model footing test results on three different sandy soils. The results of this study are encouraging as there is good agreement between the predicted and measured moduli of elasticity and settlements. Dans cet article, un modèle semi-empirique est proposé afin de prédire la variation du module d’élasticité en fonction de la succion matricielle dan des sols sableux non-saturés, en utilisant la courbe de rétention d’eau (CRE) et le module d’élasticité à saturation. Des comparaisons sont faites entre le modules d’élasticité prédits et mesurés ainsi que le tassement élastique en utilisant les résultats d’essais sur une semelle avec trois différents types de sable, et le modèle proposé. Les résultats de cette étude sont encourageants puisqu’il existe une bonne concordance entre les modules d’élasticité prédits et mesurés, ainsi qu’avec les valeurs de tassement. DEWEY : 550 ISSN : 0008-3674 En ligne : http://rparticle.web-p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?calyLang=f [...] [article] Semi-empirical model for the prediction of modulus of elasticity for unsaturated soils [texte imprimé] / Won Taek Oh, Auteur ; Sai K. Vanapalli, Auteur ; Anand J. Puppala, Auteur . - pp. 903-914. Sciences de la Terre Langues : Anglais (eng) in Canadian geotechnical journal > Vol. 46 N° 8 (Août 2009) . - pp. 903-914 Mots-clés : Modulus  of  elasticity  Soil-water  characteristic  curve  Elastic  settlement  Matric  suction  Model  footing  tests  Module  d’élasticité  Courbe  de  rétention  d’eau  Tassement  Succion  matricielle  Essais  sur  semelles  modèles Index. décimale : 550 Sciences auxiliaires de la géologie. Résumé : A semi-empirical model is proposed in this paper to predict the variation of modulus of elasticity with respect to matric suction for unsaturated sandy soils using the soil-water characteristic curve (SWCC) and the modulus of elasticity under saturated conditions. Using this model, comparisons are provided between the predicted and measured moduli of elasticity and elastic settlements from model footing test results on three different sandy soils. The results of this study are encouraging as there is good agreement between the predicted and measured moduli of elasticity and settlements. Dans cet article, un modèle semi-empirique est proposé afin de prédire la variation du module d’élasticité en fonction de la succion matricielle dan des sols sableux non-saturés, en utilisant la courbe de rétention d’eau (CRE) et le module d’élasticité à saturation. Des comparaisons sont faites entre le modules d’élasticité prédits et mesurés ainsi que le tassement élastique en utilisant les résultats d’essais sur une semelle avec trois différents types de sable, et le modèle proposé. Les résultats de cette étude sont encourageants puisqu’il existe une bonne concordance entre les modules d’élasticité prédits et mesurés, ainsi qu’avec les valeurs de tassement. DEWEY : 550 ISSN : 0008-3674 En ligne : http://rparticle.web-p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?calyLang=f [...]