Dépouillements

Performance of a PRB for the remediation of acidic groundwater in acid sulfate soil terrain / Buddhima Indraratna in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 897-906 Titre : Performance of a PRB for the remediation of acidic groundwater in acid sulfate soil terrain Type de document : texte imprimé Auteurs : Buddhima Indraratna, Auteur ; Gyanendra Regmi, Auteur ; Long Duc Nghiem, Auteur Année de publication : 2010 Article en page(s) : pp. 897-906 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Acid  sulfate  soils  Armoring  effects  Contaminated  groundwater  Permeable  reactive  barrier Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Contaminated groundwater resulting from pyrite oxidation of acid sulfate soils (ASSs) is a major environmental problem in coastal Australia. A column test was carried out for an extended period with recycled concrete to study the efficiency of the reactive materials for neutralizing acidic groundwater. Results show that the actual acid neutralization capacity of the recycled concrete could decrease to less than 50% of the theoretical value due to armoring effects. Nevertheless, the performance is good as a spot treatment in ASS Terrain using a near-zero cost waste product. Based on the test results and site characterization, a permeable reactive barrier (PRB) with recycled concrete was designed and installed in ASS terrain on the Shoalhaven River floodplain, southeastern, Australia in October 2006. The performance of the PRB was studied over two and half years to assess the potential of recycled concrete (1) to neutralize the groundwater acidity and (2) to remove the dissolved heavy metals such as iron and aluminum from in situ acidic groundwater. To date, performance monitoring of the PRB shows that recycled concrete can successfully improve the pH of groundwater from acidic to mildly alkaline. In addition, it successfully removes groundwater iron and aluminum. Results reported here also reveal a slow decrease in the performance of the PRB due to armoring effects probably caused by precipitation of iron and aluminum on the surface of the reactive recycled concrete materials. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p897_s1?isAuthorized=no [article] Performance of a PRB for the remediation of acidic groundwater in acid sulfate soil terrain [texte imprimé] / Buddhima Indraratna, Auteur ; Gyanendra Regmi, Auteur ; Long Duc Nghiem, Auteur . - 2010 . - pp. 897-906. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 897-906 Mots-clés : Acid  sulfate  soils  Armoring  effects  Contaminated  groundwater  Permeable  reactive  barrier Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Contaminated groundwater resulting from pyrite oxidation of acid sulfate soils (ASSs) is a major environmental problem in coastal Australia. A column test was carried out for an extended period with recycled concrete to study the efficiency of the reactive materials for neutralizing acidic groundwater. Results show that the actual acid neutralization capacity of the recycled concrete could decrease to less than 50% of the theoretical value due to armoring effects. Nevertheless, the performance is good as a spot treatment in ASS Terrain using a near-zero cost waste product. Based on the test results and site characterization, a permeable reactive barrier (PRB) with recycled concrete was designed and installed in ASS terrain on the Shoalhaven River floodplain, southeastern, Australia in October 2006. The performance of the PRB was studied over two and half years to assess the potential of recycled concrete (1) to neutralize the groundwater acidity and (2) to remove the dissolved heavy metals such as iron and aluminum from in situ acidic groundwater. To date, performance monitoring of the PRB shows that recycled concrete can successfully improve the pH of groundwater from acidic to mildly alkaline. In addition, it successfully removes groundwater iron and aluminum. Results reported here also reveal a slow decrease in the performance of the PRB due to armoring effects probably caused by precipitation of iron and aluminum on the surface of the reactive recycled concrete materials. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p897_s1?isAuthorized=no

Field assessment of the performance of a ballasted rail track with and without geosynthetics / Buddhima Indraratna in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 907-917 Titre : Field assessment of the performance of a ballasted rail track with and without geosynthetics Type de document : texte imprimé Auteurs : Buddhima Indraratna, Auteur ; Sanjay Nimbalkar, Auteur ; David Christie, Auteur Année de publication : 2010 Article en page(s) : pp. 907-917 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Railroad  tracks  Ballast  Cyclic  loads  Deformation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Understanding the complex mechanisms of stress transfer and strain accumulation in layers of track substructure under repeated wheel loading is essential to predict the desirable track maintenance cycle as well as the design of the new track. Various finite element and analytical techniques have been developed in the past to understand the behavior of composite track layers subjected to repeated wheel loads. The mechanical behavior of ballast is influenced by several factors, including the track confining pressure, type of aggregates, and the number of loading cycles. A field trial was conducted on an instrumented track at Bulli, New South Wales, Australia, with the specific aims of studying the benefits of a geocomposite installed at the ballast-capping interface, and to evaluate the performance of moderately graded recycled ballast in comparison to traditionally very uniform fresh ballast. It was found that recycled ballast can be effectively reused if reinforced with a geocomposite. It was also found that geocomposite can effectively reduce vertical and lateral strains of the ballast with obvious implications for improved track stability and reduced maintenance costs. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p907_s1?isAuthorized=no [article] Field assessment of the performance of a ballasted rail track with and without geosynthetics [texte imprimé] / Buddhima Indraratna, Auteur ; Sanjay Nimbalkar, Auteur ; David Christie, Auteur . - 2010 . - pp. 907-917. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 907-917 Mots-clés : Railroad  tracks  Ballast  Cyclic  loads  Deformation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Understanding the complex mechanisms of stress transfer and strain accumulation in layers of track substructure under repeated wheel loading is essential to predict the desirable track maintenance cycle as well as the design of the new track. Various finite element and analytical techniques have been developed in the past to understand the behavior of composite track layers subjected to repeated wheel loads. The mechanical behavior of ballast is influenced by several factors, including the track confining pressure, type of aggregates, and the number of loading cycles. A field trial was conducted on an instrumented track at Bulli, New South Wales, Australia, with the specific aims of studying the benefits of a geocomposite installed at the ballast-capping interface, and to evaluate the performance of moderately graded recycled ballast in comparison to traditionally very uniform fresh ballast. It was found that recycled ballast can be effectively reused if reinforced with a geocomposite. It was also found that geocomposite can effectively reduce vertical and lateral strains of the ballast with obvious implications for improved track stability and reduced maintenance costs. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p907_s1?isAuthorized=no

Centrifuge testing to evaluate and mitigate liquefaction-induced building settlement mechanisms / Shideh Dashti in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 918-929 Titre : Centrifuge testing to evaluate and mitigate liquefaction-induced building settlement mechanisms Type de document : texte imprimé Auteurs : Shideh Dashti, Auteur ; Bray, Jonathan D., Auteur ; Juan M. Pestana, Auteur Année de publication : 2010 Article en page(s) : pp. 918-929 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Centrifuge  Earthquakes  Liquefaction  Mitigation  Settlement  Shallow  foundation  Soil  structure  interaction Résumé : The effective application of liquefaction mitigation techniques requires an improved understanding of the development and consequences of liquefaction. Centrifuge experiments were performed to study the dominant mechanisms of seismically induced settlement of buildings with rigid mat foundations on thin deposits of liquefiable sand. The relative importance of key settlement mechanisms was evaluated by using mitigation techniques to minimize some of their respective contributions. The relative importance of settlement mechanisms was shown to depend on the characteristics of the earthquake motion, liquefiable soil, and building. The initiation, rate, and amount of liquefaction-induced building settlement depended greatly on the rate of ground shaking. Engineering design procedures should incorporate this important feature of earthquake shaking, which may be represented by the time rate of Arias intensity (i.e., the shaking intensity rate). In these experiments, installation of an independent, in-ground, perimetrical, stiff structural wall minimized deviatoric soil deformations under the building and reduced total building settlements by approximately 50%. Use of a flexible impermeable barrier that inhibited horizontal water flow without preventing shear deformation also reduced permanent building settlements but less significantly. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p918_s1?isAuthorized=no [article] Centrifuge testing to evaluate and mitigate liquefaction-induced building settlement mechanisms [texte imprimé] / Shideh Dashti, Auteur ; Bray, Jonathan D., Auteur ; Juan M. Pestana, Auteur . - 2010 . - pp. 918-929. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 918-929 Mots-clés : Centrifuge  Earthquakes  Liquefaction  Mitigation  Settlement  Shallow  foundation  Soil  structure  interaction Résumé : The effective application of liquefaction mitigation techniques requires an improved understanding of the development and consequences of liquefaction. Centrifuge experiments were performed to study the dominant mechanisms of seismically induced settlement of buildings with rigid mat foundations on thin deposits of liquefiable sand. The relative importance of key settlement mechanisms was evaluated by using mitigation techniques to minimize some of their respective contributions. The relative importance of settlement mechanisms was shown to depend on the characteristics of the earthquake motion, liquefiable soil, and building. The initiation, rate, and amount of liquefaction-induced building settlement depended greatly on the rate of ground shaking. Engineering design procedures should incorporate this important feature of earthquake shaking, which may be represented by the time rate of Arias intensity (i.e., the shaking intensity rate). In these experiments, installation of an independent, in-ground, perimetrical, stiff structural wall minimized deviatoric soil deformations under the building and reduced total building settlements by approximately 50%. Use of a flexible impermeable barrier that inhibited horizontal water flow without preventing shear deformation also reduced permanent building settlements but less significantly. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p918_s1?isAuthorized=no

Antioxidant depletion from a high density polyethylene geomembrane under simulated landfill conditions / R. Kerry Rowe in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 930-939 Titre : Antioxidant depletion from a high density polyethylene geomembrane under simulated landfill conditions Type de document : texte imprimé Auteurs : R. Kerry Rowe, Auteur ; M. Z. Islam, Auteur ; R. W. I. Brachman, Auteur Année de publication : 2010 Article en page(s) : pp. 930-939 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Durability  Geomembranes  Landfills  Liners  Service  life  Temperature  HDPE  Municipal  solid  waste Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Accelerated aging tests to evaluate the depletion of antioxidants from a high density polyethylene geomembrane are described. The effects of temperature, high pressure, and continuous leachate circulation on the aging of geomembranes in composite liner systems are examined. The antioxidant depletion rates (0.05, 0.19, and 0.41 month−1 at 55, 70, and 85°C, respectively) obtained for the simulated landfill liner at 250 kPa vertical pressure are consistently lower than that obtained from traditional leachate immersion tests on the same geomembrane (0.12, 0.39, and 1.1 month−1 at 55, 70, and 85°C). This difference leads to a substantial increase in antioxidant depletion times at a typical landfill liner temperature (35°C) with 40 years predicted based on the data from the landfill liner simulators tests, compared to 15 years predicted for the same geomembrane based on leachate immersion tests. In these tests, the crystallinity and tensile yield strain of the geomembrane increased in the early stages of aging and then remained relatively constant over the testing period. There was no significant change in other geomembrane properties within the testing period. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p930_s1?isAuthorized=no [article] Antioxidant depletion from a high density polyethylene geomembrane under simulated landfill conditions [texte imprimé] / R. Kerry Rowe, Auteur ; M. Z. Islam, Auteur ; R. W. I. Brachman, Auteur . - 2010 . - pp. 930-939. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 930-939 Mots-clés : Durability  Geomembranes  Landfills  Liners  Service  life  Temperature  HDPE  Municipal  solid  waste Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Accelerated aging tests to evaluate the depletion of antioxidants from a high density polyethylene geomembrane are described. The effects of temperature, high pressure, and continuous leachate circulation on the aging of geomembranes in composite liner systems are examined. The antioxidant depletion rates (0.05, 0.19, and 0.41 month−1 at 55, 70, and 85°C, respectively) obtained for the simulated landfill liner at 250 kPa vertical pressure are consistently lower than that obtained from traditional leachate immersion tests on the same geomembrane (0.12, 0.39, and 1.1 month−1 at 55, 70, and 85°C). This difference leads to a substantial increase in antioxidant depletion times at a typical landfill liner temperature (35°C) with 40 years predicted based on the data from the landfill liner simulators tests, compared to 15 years predicted for the same geomembrane based on leachate immersion tests. In these tests, the crystallinity and tensile yield strain of the geomembrane increased in the early stages of aging and then remained relatively constant over the testing period. There was no significant change in other geomembrane properties within the testing period. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p930_s1?isAuthorized=no

Parametric solutions for slide impact on pipelines / Mark F. Randolph in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 940-949 Titre : Parametric solutions for slide impact on pipelines Type de document : texte imprimé Auteurs : Mark F. Randolph, Auteur ; Donghee Seo, Auteur ; David J. White, Auteur Année de publication : 2010 Article en page(s) : pp. 940-949 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Pipeline  design  Submarine  pipelines  Soil-pipe  interactions  Landslides  Lateral  loads Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Pipelines are frequently subjected to active loading from slide events both on land and in the offshore environment. Whether the pipeline is initially buried or lying close to the surface, and whether it crosses the unstable region or lies in the path of debris originating from further away, the main principles are unchanged. The pipeline will be subjected to active loading over some defined length, related to the width of the slide, and as it deforms will be restrained by transverse and longitudinal resistance in adjacent passive zones. Ultimately the pipeline may come to a stable deformed shape where the continued active loading from the slide is equilibrated by the membrane tension in the pipeline in addition to the passive resistance. This problem has been explored by various writers and these principles are well established. However, to date no attempt has been made to develop a standard set of parametric solutions, which is the purpose of the current paper. Both analytical and numerical solutions of the problem have been developed, initially for slides acting normal to the pipeline but later extended to general conditions with the slide impacting the pipeline at some angle. It is shown that analytical solutions based on certain idealizations maintain their accuracy over a wide parameter range, and the net effect of the slide in terms of stresses induced in the pipe wall and maximum displacement of the pipeline may be captured in appropriate dimensionless groups. Design charts are presented for slide widths of up to 10,000 times the pipeline diameter for a practical range of other parameters such as the ratios of passive normal and frictional resistance to the active loading. Although the solutions are limited by some of the idealizations, they should provide a useful starting point in design, providing a framework for a more detailed numerical analysis for the particular governing conditions. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p940_s1?isAuthorized=no [article] Parametric solutions for slide impact on pipelines [texte imprimé] / Mark F. Randolph, Auteur ; Donghee Seo, Auteur ; David J. White, Auteur . - 2010 . - pp. 940-949. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 940-949 Mots-clés : Pipeline  design  Submarine  pipelines  Soil-pipe  interactions  Landslides  Lateral  loads Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Pipelines are frequently subjected to active loading from slide events both on land and in the offshore environment. Whether the pipeline is initially buried or lying close to the surface, and whether it crosses the unstable region or lies in the path of debris originating from further away, the main principles are unchanged. The pipeline will be subjected to active loading over some defined length, related to the width of the slide, and as it deforms will be restrained by transverse and longitudinal resistance in adjacent passive zones. Ultimately the pipeline may come to a stable deformed shape where the continued active loading from the slide is equilibrated by the membrane tension in the pipeline in addition to the passive resistance. This problem has been explored by various writers and these principles are well established. However, to date no attempt has been made to develop a standard set of parametric solutions, which is the purpose of the current paper. Both analytical and numerical solutions of the problem have been developed, initially for slides acting normal to the pipeline but later extended to general conditions with the slide impacting the pipeline at some angle. It is shown that analytical solutions based on certain idealizations maintain their accuracy over a wide parameter range, and the net effect of the slide in terms of stresses induced in the pipe wall and maximum displacement of the pipeline may be captured in appropriate dimensionless groups. Design charts are presented for slide widths of up to 10,000 times the pipeline diameter for a practical range of other parameters such as the ratios of passive normal and frictional resistance to the active loading. Although the solutions are limited by some of the idealizations, they should provide a useful starting point in design, providing a framework for a more detailed numerical analysis for the particular governing conditions. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p940_s1?isAuthorized=no

Physical modeling of lateral clay-pipe interaction / José R. M. S. Oliveira in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 950-956 Titre : Physical modeling of lateral clay-pipe interaction Type de document : texte imprimé Auteurs : José R. M. S. Oliveira, Auteur ; Marcio S. S. Almeida, Auteur ; Maria C. F. Almeida, Auteur Année de publication : 2010 Article en page(s) : pp. 950-956 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Soft  soils  Pipelines  Soil-structure  interaction  Model  tests Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents results from physical model testing of lateral clay-pipe interaction. The main reason for this research was the accident in Rio de Janeiro in January 2000 when more than 1×106 l of crude oil was spilled into Guanabara Bay due to thermal buckling of a pipeline. A set of centrifuge tests was performed for a model pipeline at shallow burial depths in order to assess the lateral resistance of the soft clay from the incident site. In addition, a set of 1-g model tests was also performed to observe the failure mechanism in more detail. These tests permitted the development of an analytical model, based on geotechnical and geometrical parameters, able to evaluate the soil resistance when subjected to lateral pipe movements for shallow burial depths. The centrifuge data are then compared with the proposed analytical model and with literature data, revealing good agreement in both cases. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p950_s1?isAuthorized=no [article] Physical modeling of lateral clay-pipe interaction [texte imprimé] / José R. M. S. Oliveira, Auteur ; Marcio S. S. Almeida, Auteur ; Maria C. F. Almeida, Auteur . - 2010 . - pp. 950-956. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 950-956 Mots-clés : Soft  soils  Pipelines  Soil-structure  interaction  Model  tests Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents results from physical model testing of lateral clay-pipe interaction. The main reason for this research was the accident in Rio de Janeiro in January 2000 when more than 1×106 l of crude oil was spilled into Guanabara Bay due to thermal buckling of a pipeline. A set of centrifuge tests was performed for a model pipeline at shallow burial depths in order to assess the lateral resistance of the soft clay from the incident site. In addition, a set of 1-g model tests was also performed to observe the failure mechanism in more detail. These tests permitted the development of an analytical model, based on geotechnical and geometrical parameters, able to evaluate the soil resistance when subjected to lateral pipe movements for shallow burial depths. The centrifuge data are then compared with the proposed analytical model and with literature data, revealing good agreement in both cases. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p950_s1?isAuthorized=no

Shear strength in preexisting landslides / Timothy D. Stark in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 957-962 Titre : Shear strength in preexisting landslides Type de document : texte imprimé Auteurs : Timothy D. Stark, Auteur ; Manzoor Hussain, Auteur Année de publication : 2010 Article en page(s) : pp. 957-962 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Soil  mechanics  Landslides  Overconsolidated  clays  Shear  strength  Strength  recovery  Slope  stability  Ring  shear  test Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Drained residual shear strength is used for the analysis of slopes containing preexisting shear surfaces. Some recent research suggests that preexisting shear surfaces in prior landslides can gain strength with time. Torsional ring and direct shear tests performed during this study show that the recovered shear strength measured in the laboratory is only noticeably greater than the drained residual strength at effective normal stress of 100 kPa or less. The test results also show that the recovered strength even at effective normal stresses of 100 kPa or less is lost after a small shear displacement, i.e., slope movement. An effective normal stress of 100 kPa corresponds to a shallow depth so the observed strength gain has little, if any, impact on the analysis of deep landslides. This paper describes the laboratory strength recovery testing and the results for soils with different plasticities at various rest periods and effective normal stresses. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p957_s1?isAuthorized=no [article] Shear strength in preexisting landslides [texte imprimé] / Timothy D. Stark, Auteur ; Manzoor Hussain, Auteur . - 2010 . - pp. 957-962. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 957-962 Mots-clés : Soil  mechanics  Landslides  Overconsolidated  clays  Shear  strength  Strength  recovery  Slope  stability  Ring  shear  test Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Drained residual shear strength is used for the analysis of slopes containing preexisting shear surfaces. Some recent research suggests that preexisting shear surfaces in prior landslides can gain strength with time. Torsional ring and direct shear tests performed during this study show that the recovered shear strength measured in the laboratory is only noticeably greater than the drained residual strength at effective normal stress of 100 kPa or less. The test results also show that the recovered strength even at effective normal stresses of 100 kPa or less is lost after a small shear displacement, i.e., slope movement. An effective normal stress of 100 kPa corresponds to a shallow depth so the observed strength gain has little, if any, impact on the analysis of deep landslides. This paper describes the laboratory strength recovery testing and the results for soils with different plasticities at various rest periods and effective normal stresses. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p957_s1?isAuthorized=no

Unsaturated infinite slope stability considering surface flux conditions / Quentin B. Travis in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 963-974 Titre : Unsaturated infinite slope stability considering surface flux conditions Type de document : texte imprimé Auteurs : Quentin B. Travis, Auteur ; Sandra L. Houston, Auteur ; Fernando A. M. Marinho, Auteur Année de publication : 2010 Article en page(s) : pp. 963-974 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Cohesive  soils  Embankment  stability  Equilibrium  Failures  Landslides  Limit  equilibrium  Pore  pressure  Pore  water  Pore-water  pressure  Slope  stability  Slopes  Soil  suction  Stability  Suction  Unsaturated  flow  Unsaturated  soils Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A slope stability model is derived for an infinite slope subjected to unsaturated infiltration flow above a phreatic surface. Closed form steady state solutions are derived for the matric suction and degree of saturation profiles. Soil unit weight, consistent with the degree of saturation profile, is also directly calculated and introduced into the analyzes, resulting in closed-form solutions for typical soil parameters and an infinite series solution for arbitrary soil parameters. The solutions are coupled with the infinite slope stability equations to establish a fully realized safety factor function. In general, consideration of soil suction results in higher factor of safety. The increase in shear strength due to the inclusion of soil suction is analogous to making an addition to the cohesion, which, of course, increases the factor of safety against sliding. However, for cohesive soils, the results show lower safety factors for slip surfaces approaching the phreatic surface compared to those produced by common safety factor calculations. The lower factor of safety is due to the increased soil unit weight considered in the matric suction model but not usually accounted for in practice wherein the soil is treated as dry above the phreatic surface. The developed model is verified with a published case study, correctly predicting stability under dry conditions and correctly predicting failure for a particular storm. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p963_s1?isAuthorized=no [article] Unsaturated infinite slope stability considering surface flux conditions [texte imprimé] / Quentin B. Travis, Auteur ; Sandra L. Houston, Auteur ; Fernando A. M. Marinho, Auteur . - 2010 . - pp. 963-974. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 963-974 Mots-clés : Cohesive  soils  Embankment  stability  Equilibrium  Failures  Landslides  Limit  equilibrium  Pore  pressure  Pore  water  Pore-water  pressure  Slope  stability  Slopes  Soil  suction  Stability  Suction  Unsaturated  flow  Unsaturated  soils Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A slope stability model is derived for an infinite slope subjected to unsaturated infiltration flow above a phreatic surface. Closed form steady state solutions are derived for the matric suction and degree of saturation profiles. Soil unit weight, consistent with the degree of saturation profile, is also directly calculated and introduced into the analyzes, resulting in closed-form solutions for typical soil parameters and an infinite series solution for arbitrary soil parameters. The solutions are coupled with the infinite slope stability equations to establish a fully realized safety factor function. In general, consideration of soil suction results in higher factor of safety. The increase in shear strength due to the inclusion of soil suction is analogous to making an addition to the cohesion, which, of course, increases the factor of safety against sliding. However, for cohesive soils, the results show lower safety factors for slip surfaces approaching the phreatic surface compared to those produced by common safety factor calculations. The lower factor of safety is due to the increased soil unit weight considered in the matric suction model but not usually accounted for in practice wherein the soil is treated as dry above the phreatic surface. The developed model is verified with a published case study, correctly predicting stability under dry conditions and correctly predicting failure for a particular storm. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p963_s1?isAuthorized=no

Probabilistic assessment of slope stability that considers the spatial variability of soil properties / Sung Eun Cho in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 975-984 Titre : Probabilistic assessment of slope stability that considers the spatial variability of soil properties Type de document : texte imprimé Auteurs : Sung Eun Cho, Auteur Année de publication : 2010 Article en page(s) : pp. 975-984 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Slope  stability  Monte  Carlo  method  Probability  Failures  Limit  equilibrium Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In this paper, a numerical procedure for probabilistic slope stability analysis is presented. This procedure extends the traditional limit equilibrium method of slices to a probabilistic approach that accounts for the uncertainties and spatial variation of the soil strength parameters. In this study, two-dimensional random fields were generated based on a Karhunen-Loève expansion in a fashion consistent with a specified marginal distribution function and an autocorrelation function. A Monte Carlo simulation was then used to determine the statistical response based on the generated random fields. This approach makes no assumption about the critical failure surface. Rather, the critical failure surface corresponding to the input random fields of soil properties is searched during the process of analysis. A series of analyses was performed to verify the application potential of the proposed method and to study the effects of uncertainty due to the spatial heterogeneity on the stability of slope. The results show that the proposed method can efficiently consider the various failure mechanisms caused by the spatial variability of soil property in the probabilistic slope stability assessment. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p975_s1?isAuthorized=no [article] Probabilistic assessment of slope stability that considers the spatial variability of soil properties [texte imprimé] / Sung Eun Cho, Auteur . - 2010 . - pp. 975-984. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 975-984 Mots-clés : Slope  stability  Monte  Carlo  method  Probability  Failures  Limit  equilibrium Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In this paper, a numerical procedure for probabilistic slope stability analysis is presented. This procedure extends the traditional limit equilibrium method of slices to a probabilistic approach that accounts for the uncertainties and spatial variation of the soil strength parameters. In this study, two-dimensional random fields were generated based on a Karhunen-Loève expansion in a fashion consistent with a specified marginal distribution function and an autocorrelation function. A Monte Carlo simulation was then used to determine the statistical response based on the generated random fields. This approach makes no assumption about the critical failure surface. Rather, the critical failure surface corresponding to the input random fields of soil properties is searched during the process of analysis. A series of analyses was performed to verify the application potential of the proposed method and to study the effects of uncertainty due to the spatial heterogeneity on the stability of slope. The results show that the proposed method can efficiently consider the various failure mechanisms caused by the spatial variability of soil property in the probabilistic slope stability assessment. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p975_s1?isAuthorized=no

Wall and ground movements due to deep excavations in Shanghai soft soils / J. H. Wang in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 985-994 Titre : Wall and ground movements due to deep excavations in Shanghai soft soils Type de document : texte imprimé Auteurs : J. H. Wang, Auteur ; Xu, Z. X., Auteur ; W. D. Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 985-994 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Database  Deep  excavation  Wall  deflection  Ground  settlement  Soft  soil  Shanghai Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : An extensive database of 300 case histories of wall displacements and ground settlements due to deep excavations in Shanghai soft soils were collected and analyzed. The mean values of the maximum lateral displacements of walls constructed by the top-down method, walls constructed by the bottom-up method (including diaphragm walls, contiguous pile walls, and compound deep soil mixing walls), sheet pile walls, compound soil nail walls, and deep soil mixing walls are 0.27%H, 0.4%H, 1.5%H, 0.55%H, and 0.91%H, respectively, where H is the excavation depth. The mean value of the maximum ground surface settlement is 0.42%H. The settlement influence zone reaches to a distance of about 1.5H to 3.5H from the excavation. The ratio between the maximum ground surface settlement and the maximum lateral displacement of a wall generally ranges from 0.4 to 2.0, with an average value of 0.9. The factors affecting the deformation of the wall were analyzed. It shows that there is a slight evidence of a trend for decreasing wall displacement with increasing system stiffness and the factor of safety against basal heave. Wall and ground movements were also compared with that observed in worldwide case histories. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p985_s1?isAuthorized=no [article] Wall and ground movements due to deep excavations in Shanghai soft soils [texte imprimé] / J. H. Wang, Auteur ; Xu, Z. X., Auteur ; W. D. Wang, Auteur . - 2010 . - pp. 985-994. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 985-994 Mots-clés : Database  Deep  excavation  Wall  deflection  Ground  settlement  Soft  soil  Shanghai Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : An extensive database of 300 case histories of wall displacements and ground settlements due to deep excavations in Shanghai soft soils were collected and analyzed. The mean values of the maximum lateral displacements of walls constructed by the top-down method, walls constructed by the bottom-up method (including diaphragm walls, contiguous pile walls, and compound deep soil mixing walls), sheet pile walls, compound soil nail walls, and deep soil mixing walls are 0.27%H, 0.4%H, 1.5%H, 0.55%H, and 0.91%H, respectively, where H is the excavation depth. The mean value of the maximum ground surface settlement is 0.42%H. The settlement influence zone reaches to a distance of about 1.5H to 3.5H from the excavation. The ratio between the maximum ground surface settlement and the maximum lateral displacement of a wall generally ranges from 0.4 to 2.0, with an average value of 0.9. The factors affecting the deformation of the wall were analyzed. It shows that there is a slight evidence of a trend for decreasing wall displacement with increasing system stiffness and the factor of safety against basal heave. Wall and ground movements were also compared with that observed in worldwide case histories. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p985_s1?isAuthorized=no

Reliability analysis of earth dams / G. L. Sivakumar Babu in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 995-1009 Titre : Reliability analysis of earth dams Type de document : texte imprimé Auteurs : G. L. Sivakumar Babu, Auteur ; Amit Srivastava, Auteur Année de publication : 2010 Article en page(s) : pp. 995-1009 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Reliability  Earthen  dams  Seismic  effects  Dam  safety Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In the present study, results of reliability analyses of four selected rehabilitated earth dam sections, i.e., Chang, Tapar, Rudramata, and Kaswati, under pseudostatic loading conditions, are presented. Using the response surface methodology, in combination with first order reliability method and numerical analysis, the reliability index (β) values are obtained and results are interpreted in conjunction with conventional factor of safety values. The influence of considering variability in the input soil shear strength parameters, horizontal seismic coefficient (αh), and location of reservoir full level on the stability assessment of the earth dam sections is discussed in the probabilistic framework. A comparison of results with those obtained from other method of reliability analysis, viz., Monte Carlo simulations combined with limit equilibrium approach, provided a basis for discussing the stability of earth dams in probabilistic terms, and the results of the analysis suggest that the considered earth dam sections are reliable and are expected to perform satisfactorily. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p995_s1?isAuthorized=no [article] Reliability analysis of earth dams [texte imprimé] / G. L. Sivakumar Babu, Auteur ; Amit Srivastava, Auteur . - 2010 . - pp. 995-1009. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 995-1009 Mots-clés : Reliability  Earthen  dams  Seismic  effects  Dam  safety Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In the present study, results of reliability analyses of four selected rehabilitated earth dam sections, i.e., Chang, Tapar, Rudramata, and Kaswati, under pseudostatic loading conditions, are presented. Using the response surface methodology, in combination with first order reliability method and numerical analysis, the reliability index (β) values are obtained and results are interpreted in conjunction with conventional factor of safety values. The influence of considering variability in the input soil shear strength parameters, horizontal seismic coefficient (αh), and location of reservoir full level on the stability assessment of the earth dam sections is discussed in the probabilistic framework. A comparison of results with those obtained from other method of reliability analysis, viz., Monte Carlo simulations combined with limit equilibrium approach, provided a basis for discussing the stability of earth dams in probabilistic terms, and the results of the analysis suggest that the considered earth dam sections are reliable and are expected to perform satisfactorily. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p995_s1?isAuthorized=no

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