Dépouillements

Diffusive transport of VOCs through LLDPE and two coextruded geomembranes / Rebecca S. McWatters in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1167-1177 Titre : Diffusive transport of VOCs through LLDPE and two coextruded geomembranes Type de document : texte imprimé Auteurs : Rebecca S. McWatters, Auteur ; R. Kerry Rowe, Auteur Année de publication : 2010 Article en page(s) : pp. 1167-1177 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Geomembranes  Diffusion  Permeability  Volatile  organic  chemicals  Barrier Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : The diffusive properties of two coextruded geomembranes, one with a polyamide inner core and the other with an ethylene vinyl-alcohol (EVOH) inner core, and a standard 0.53-mm (20-mil) linear low-density polyethylene (LLDPE) geomembrane were examined. Diffusion and sorption laboratory tests were performed to estimate the parameters controlling diffusive migration, including the partitioning, diffusion, and permeation coefficients of the geomembrane in both the aqueous and vapor phases. Results indicate a significant reduction in mass flux through the coextruded geomembranes compared to conventional LLDPE. The EVOH coextruded geomembrane had the lowest permeation coefficients (Pg) with a range of (2–6)×10−12 m2 s−1 for diffusion from the aqueous phase. These values for EVOH are upper bounds and the actual values may be lower than as stated. The polyamide (nylon) coextruded geomembrane had higher values than for EVOH, with a Pg range of (0.7–2.2)×10−11 m2 s−1 from the aqueous phase. The highest permeation coefficients were for the standard 20-mil LLDPE, which ranged from (0.6–1.1)×10−10 m2 s−1. Thus the permeation coefficient for LLDPE was about one order of magnitude greater than for the nylon coextruded and at least two orders of magnitudes higher than for the EVOH coextruded geomembrane. Both coextruded geomembranes showed decreased Pg values and therefore improved diffusive resistance to volatile organic compounds over traditional 0.56-mm PVC geomembranes. The EVOH geomembrane showed a 5–12-fold decrease in Pg in comparison to a 2.0-mm high density polyethylene geomembrane. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1167_s1?isAuthorized=no [article] Diffusive transport of VOCs through LLDPE and two coextruded geomembranes [texte imprimé] / Rebecca S. McWatters, Auteur ; R. Kerry Rowe, Auteur . - 2010 . - pp. 1167-1177. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1167-1177 Mots-clés : Geomembranes  Diffusion  Permeability  Volatile  organic  chemicals  Barrier Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : The diffusive properties of two coextruded geomembranes, one with a polyamide inner core and the other with an ethylene vinyl-alcohol (EVOH) inner core, and a standard 0.53-mm (20-mil) linear low-density polyethylene (LLDPE) geomembrane were examined. Diffusion and sorption laboratory tests were performed to estimate the parameters controlling diffusive migration, including the partitioning, diffusion, and permeation coefficients of the geomembrane in both the aqueous and vapor phases. Results indicate a significant reduction in mass flux through the coextruded geomembranes compared to conventional LLDPE. The EVOH coextruded geomembrane had the lowest permeation coefficients (Pg) with a range of (2–6)×10−12 m2 s−1 for diffusion from the aqueous phase. These values for EVOH are upper bounds and the actual values may be lower than as stated. The polyamide (nylon) coextruded geomembrane had higher values than for EVOH, with a Pg range of (0.7–2.2)×10−11 m2 s−1 from the aqueous phase. The highest permeation coefficients were for the standard 20-mil LLDPE, which ranged from (0.6–1.1)×10−10 m2 s−1. Thus the permeation coefficient for LLDPE was about one order of magnitude greater than for the nylon coextruded and at least two orders of magnitudes higher than for the EVOH coextruded geomembrane. Both coextruded geomembranes showed decreased Pg values and therefore improved diffusive resistance to volatile organic compounds over traditional 0.56-mm PVC geomembranes. The EVOH geomembrane showed a 5–12-fold decrease in Pg in comparison to a 2.0-mm high density polyethylene geomembrane. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1167_s1?isAuthorized=no

Dynamic compaction of collapsible soils based on U.S. case histories / Kyle M. Rollins in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1178-1186 Titre : Dynamic compaction of collapsible soils based on U.S. case histories Type de document : texte imprimé Auteurs : Kyle M. Rollins, Auteur ; Jihyoung Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 1178-1186 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Collapsible  soils  Compaction  Dynamic  compaction  Soil  improvement  Vibration Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Dynamic compaction (DC) is an economical approach for mitigating the hazard posed by collapsible soils particularly when they are deeper than 3–4 m. In this paper, case histories are provided for 15 projects at 10 locations in the United States where collapsible soils were treated with DC. For each site the soil properties, compaction procedures, and subsequent improvement are summarized. Although cohesionless and low-plasticity collapsible soils were successfully compacted, clay layers in the profile appeared to absorb energy and severely reduced compaction effectiveness. Correlations are presented for estimating the maximum depth of improvement, the degree of improvement versus depth, the depth of craters, and the level of vibration based on measurements made at the various sites. The compactive energy per volume was typically higher than for noncollapsible soils because collapsible soils are usually loose but relatively stiff. The maximum depth of improvement was similar to that for noncollapsible soils; however, significant scatter was observed about the best-fit line. Improvement was nonuniform with nearly 80% of the total improvement occurring within the top 60% of the improvement zone. The crater depth was related to a number of factors besides the drop energy including the number of drops, drop spacing, and contact pressure. The peak particle velocities were typically lower than those for noncollapsible soils at shorter distances, but the vibrations attenuated more slowly with distance. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1178_s1?isAuthorized=no [article] Dynamic compaction of collapsible soils based on U.S. case histories [texte imprimé] / Kyle M. Rollins, Auteur ; Jihyoung Kim, Auteur . - 2010 . - pp. 1178-1186. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1178-1186 Mots-clés : Collapsible  soils  Compaction  Dynamic  compaction  Soil  improvement  Vibration Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Dynamic compaction (DC) is an economical approach for mitigating the hazard posed by collapsible soils particularly when they are deeper than 3–4 m. In this paper, case histories are provided for 15 projects at 10 locations in the United States where collapsible soils were treated with DC. For each site the soil properties, compaction procedures, and subsequent improvement are summarized. Although cohesionless and low-plasticity collapsible soils were successfully compacted, clay layers in the profile appeared to absorb energy and severely reduced compaction effectiveness. Correlations are presented for estimating the maximum depth of improvement, the degree of improvement versus depth, the depth of craters, and the level of vibration based on measurements made at the various sites. The compactive energy per volume was typically higher than for noncollapsible soils because collapsible soils are usually loose but relatively stiff. The maximum depth of improvement was similar to that for noncollapsible soils; however, significant scatter was observed about the best-fit line. Improvement was nonuniform with nearly 80% of the total improvement occurring within the top 60% of the improvement zone. The crater depth was related to a number of factors besides the drop energy including the number of drops, drop spacing, and contact pressure. The peak particle velocities were typically lower than those for noncollapsible soils at shorter distances, but the vibrations attenuated more slowly with distance. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1178_s1?isAuthorized=no

Seismic behavior of batter piles / A. Giannakou in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1187-1199 Titre : Seismic behavior of batter piles : elastic response Type de document : texte imprimé Auteurs : A. Giannakou, Auteur ; N. Gerolymos, Auteur ; G. Gazetas, Auteur Année de publication : 2010 Article en page(s) : pp. 1187-1199 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Batter  piles  Lateral  loading  Seismic  response  Numerical  modeling  Kinematic  response  Inertial  response  Soil-structure  interaction Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Several aspects of the seismic response of groups containing nonvertical piles are studied, including the lateral pile-head stiffnesses, the “kinematic” pile deformation, and the “inertial” soil-pile-structure response. A key goal is to explore the conditions under which the presence of batter piles is beneficial, indifferent, or detrimental. Parametric analyses are carried out using three-dimensional finite-element modeling, assuming elastic behavior of soil, piles, and superstructure. The model is first used to obtain the lateral stiffnesses of single batter piles and to show that its results converge to the available solutions from the literature. Then, real accelerograms covering a broad range of frequency characteristics are employed as base excitation of simple fixed-head two-pile group configurations, embedded in homogeneous, inhomogeneous, and layered soil profiles, while supporting very tall or very short structures. Five pile inclinations are considered while the corresponding vertical-pile group results serve as reference. It is found that in purely kinematic seismic loading, batter piles tend to confirm their negative reputation, as had also been found recently for a group subjected to static horizontal ground deformation. However, the total (kinematic plus inertial) response of structural systems founded on groups of batter piles offers many reasons for optimism. Batter piles may indeed be beneficial (or detrimental) depending on, among other parameters, the relative size of the overturning moment versus the shear force transmitted onto them from the superstructure. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1187_s1?isAuthorized=no [article] Seismic behavior of batter piles : elastic response [texte imprimé] / A. Giannakou, Auteur ; N. Gerolymos, Auteur ; G. Gazetas, Auteur . - 2010 . - pp. 1187-1199. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1187-1199 Mots-clés : Batter  piles  Lateral  loading  Seismic  response  Numerical  modeling  Kinematic  response  Inertial  response  Soil-structure  interaction Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Several aspects of the seismic response of groups containing nonvertical piles are studied, including the lateral pile-head stiffnesses, the “kinematic” pile deformation, and the “inertial” soil-pile-structure response. A key goal is to explore the conditions under which the presence of batter piles is beneficial, indifferent, or detrimental. Parametric analyses are carried out using three-dimensional finite-element modeling, assuming elastic behavior of soil, piles, and superstructure. The model is first used to obtain the lateral stiffnesses of single batter piles and to show that its results converge to the available solutions from the literature. Then, real accelerograms covering a broad range of frequency characteristics are employed as base excitation of simple fixed-head two-pile group configurations, embedded in homogeneous, inhomogeneous, and layered soil profiles, while supporting very tall or very short structures. Five pile inclinations are considered while the corresponding vertical-pile group results serve as reference. It is found that in purely kinematic seismic loading, batter piles tend to confirm their negative reputation, as had also been found recently for a group subjected to static horizontal ground deformation. However, the total (kinematic plus inertial) response of structural systems founded on groups of batter piles offers many reasons for optimism. Batter piles may indeed be beneficial (or detrimental) depending on, among other parameters, the relative size of the overturning moment versus the shear force transmitted onto them from the superstructure. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1187_s1?isAuthorized=no

Effects of the source on wave propagation in pile integrity testing / Hua-You Chai in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1200-1208 Titre : Effects of the source on wave propagation in pile integrity testing Type de document : texte imprimé Auteurs : Hua-You Chai, Auteur ; Phoon, Kok-Kwang, Auteur ; Dian-Ji Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 1200-1208 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Longitudinal  mode  Rayleigh  waves  Dispersion  Low-strain  integrity  testing  of  piles  Pulse  echo  method Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : One-dimensional stress wave theory is widely used to analyze quantitatively the reflections in low-strain integrity testing of piles. However, a point or disk loading produces body and Rayleigh waves near the pile top. The multireflections of these waves from the lateral surface of a pile are present in the wave field near the pile top. Effects of three-dimensional waves on the near field responses are obvious. These effects can be interpreted erroneously by an inexperienced user as “noises” or “pile anomalies.” To investigate wave propagation in the longitudinal direction, the behavior of the waves in the far field (some distance below the pile top) is studied by theoretical analysis of the longitudinal modes in free cylinders and numerical simulations. The wave pattern at the pile top is analyzed based on the response of an elastic half-space to a harmonic disk loading. The results show that when the ratio of the characteristic length of an impact pulse to the cylinder radius is large enough, the components of Rayleigh waves in the wave field at the pile top are diminished; the waves in the far field behave approximately as plane waves; the responses at positions between 1/2R and 3/4R from the pile axis are less affected by the multireflections. The results from numerical simulations support the practical recommendation to use a ratio of characteristic wavelength to pile radius larger than four. Under this condition, the reflections from the far field (say deeper than two pile diameters) can be analyzed from the responses at receiver positions about 0.6R from the pile axis based on one-dimensional stress wave theory. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1200_s1?isAuthorized=no [article] Effects of the source on wave propagation in pile integrity testing [texte imprimé] / Hua-You Chai, Auteur ; Phoon, Kok-Kwang, Auteur ; Dian-Ji Zhang, Auteur . - 2010 . - pp. 1200-1208. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1200-1208 Mots-clés : Longitudinal  mode  Rayleigh  waves  Dispersion  Low-strain  integrity  testing  of  piles  Pulse  echo  method Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : One-dimensional stress wave theory is widely used to analyze quantitatively the reflections in low-strain integrity testing of piles. However, a point or disk loading produces body and Rayleigh waves near the pile top. The multireflections of these waves from the lateral surface of a pile are present in the wave field near the pile top. Effects of three-dimensional waves on the near field responses are obvious. These effects can be interpreted erroneously by an inexperienced user as “noises” or “pile anomalies.” To investigate wave propagation in the longitudinal direction, the behavior of the waves in the far field (some distance below the pile top) is studied by theoretical analysis of the longitudinal modes in free cylinders and numerical simulations. The wave pattern at the pile top is analyzed based on the response of an elastic half-space to a harmonic disk loading. The results show that when the ratio of the characteristic length of an impact pulse to the cylinder radius is large enough, the components of Rayleigh waves in the wave field at the pile top are diminished; the waves in the far field behave approximately as plane waves; the responses at positions between 1/2R and 3/4R from the pile axis are less affected by the multireflections. The results from numerical simulations support the practical recommendation to use a ratio of characteristic wavelength to pile radius larger than four. Under this condition, the reflections from the far field (say deeper than two pile diameters) can be analyzed from the responses at receiver positions about 0.6R from the pile axis based on one-dimensional stress wave theory. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1200_s1?isAuthorized=no

Time effects relate to crushing in sand / Hamid Karimpour in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1209-1219 Titre : Time effects relate to crushing in sand Type de document : texte imprimé Auteurs : Hamid Karimpour, Auteur ; Poul V. Lade, Auteur Année de publication : 2010 Article en page(s) : pp. 1209-1219 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Creep  Crushing  Granular  materials  Sand,  Soil  properties  Strain  rate  Time  dependence  Triaxial  tests Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Based on previously obtained experimental results, a mechanistic picture of time effects in granular materials is presented. Accordingly, time effects are caused by grain crushing, which in turn is time dependent, as indicated by static fatigue of brittle materials. Triaxial compression tests have been performed on Virginia Beach sand at high pressures, where grain crushing is prevalent, to study effects of initial loading strain rates on subsequent amounts of creep and stress relaxation. Grain size distribution curves were determined after each test and the amount of crushing, as characterized by Hardin’s breakage factor, is related to the energy input to the triaxial specimens. A pattern emerges that indicates the importance of crushing for the axial and volumetric strains, while rearrangement and frictional sliding between intact grains play much smaller roles in the stress-strain and volume change behaviors of granular materials at high stresses and shear strains. Because particle crushing is a time-dependent phenomenon described as static fatigue or delayed fracture, the close relation between time effects and crushing in granular materials is established. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1209_s1?isAuthorized=no [article] Time effects relate to crushing in sand [texte imprimé] / Hamid Karimpour, Auteur ; Poul V. Lade, Auteur . - 2010 . - pp. 1209-1219. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1209-1219 Mots-clés : Creep  Crushing  Granular  materials  Sand,  Soil  properties  Strain  rate  Time  dependence  Triaxial  tests Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Based on previously obtained experimental results, a mechanistic picture of time effects in granular materials is presented. Accordingly, time effects are caused by grain crushing, which in turn is time dependent, as indicated by static fatigue of brittle materials. Triaxial compression tests have been performed on Virginia Beach sand at high pressures, where grain crushing is prevalent, to study effects of initial loading strain rates on subsequent amounts of creep and stress relaxation. Grain size distribution curves were determined after each test and the amount of crushing, as characterized by Hardin’s breakage factor, is related to the energy input to the triaxial specimens. A pattern emerges that indicates the importance of crushing for the axial and volumetric strains, while rearrangement and frictional sliding between intact grains play much smaller roles in the stress-strain and volume change behaviors of granular materials at high stresses and shear strains. Because particle crushing is a time-dependent phenomenon described as static fatigue or delayed fracture, the close relation between time effects and crushing in granular materials is established. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1209_s1?isAuthorized=no

Groundwater modeling for the analysis of active slow-moving landslides / Leonardo Cascini in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1220-1230 Titre : Groundwater modeling for the analysis of active slow-moving landslides Type de document : texte imprimé Auteurs : Leonardo Cascini, Auteur ; Michele Calvello, Auteur ; Giuseppe M. Grimaldi, Auteur Année de publication : 2010 Article en page(s) : pp. 1220-1230 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Active  slow-moving  landslides  Groundwater  modeling  Landslides  displacement  scenarios Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Active slow-moving landslides in clayey soils exhibit continuous movements generally controlled both in the accelerating and decelerating phases by the pore-water pressure regime that, in turn, is strictly correlated to the net rainfall regime. The paper stresses the importance of a reliable groundwater model to predict these types of movements. To this aim a procedure is proposed to define the transient groundwater regime in the slope on the basis of recorded rainfall and monitoring data; the model is then used to derive the time-dependent shear strength along the main slip surfaces. The displacements at selected points along the slip surface are computed using a phenomenological (i.e., empirical) relationship between the local factor of safety and the displacement rate at those points. The procedure is employed for the analysis of a well-documented case history: the Porta Cassia landslide (central Italy). DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1220_s1?isAuthorized=no [article] Groundwater modeling for the analysis of active slow-moving landslides [texte imprimé] / Leonardo Cascini, Auteur ; Michele Calvello, Auteur ; Giuseppe M. Grimaldi, Auteur . - 2010 . - pp. 1220-1230. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1220-1230 Mots-clés : Active  slow-moving  landslides  Groundwater  modeling  Landslides  displacement  scenarios Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Active slow-moving landslides in clayey soils exhibit continuous movements generally controlled both in the accelerating and decelerating phases by the pore-water pressure regime that, in turn, is strictly correlated to the net rainfall regime. The paper stresses the importance of a reliable groundwater model to predict these types of movements. To this aim a procedure is proposed to define the transient groundwater regime in the slope on the basis of recorded rainfall and monitoring data; the model is then used to derive the time-dependent shear strength along the main slip surfaces. The displacements at selected points along the slip surface are computed using a phenomenological (i.e., empirical) relationship between the local factor of safety and the displacement rate at those points. The procedure is employed for the analysis of a well-documented case history: the Porta Cassia landslide (central Italy). DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1220_s1?isAuthorized=no

Physical characterization of municipal solid waste for geotechnical purposes / Dimitrios Zekkos in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1231-1241 Titre : Physical characterization of municipal solid waste for geotechnical purposes Type de document : texte imprimé Auteurs : Dimitrios Zekkos, Auteur ; Edward Jr Kavazanjian, Auteur ; Bray, Jonathan D., Auteur Année de publication : 2010 Article en page(s) : pp. 1231-1241 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Municipal  solid  waste  Organic  content  Water  content  Waste  classification  Waste  Landfills  Geotechnical  characterization Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A procedure to characterize municipal solid waste (MSW) for geotechnical engineering purposes is developed based on experience with waste characterization and testing. Existing MSW classification systems are reviewed briefly, and the field and laboratory waste characterization programs of two important projects are presented. Findings on the influence of the waste’s physical composition on its mechanical response from these projects and recent studies of MSW are integrated to develop a waste characterization procedure for efficient collection of the relevant information on landfill operation and waste physical characteristics that are most likely to affect the geotechnical properties of MSW. A phased approach to implementation of this procedure is proposed as a best practice for the physical characterization of MSW for geotechnical purposes. The scope of the phased procedure can be adjusted to optimize the effort required to collect relevant information on a project-specific basis. The procedure includes a systematic evaluation of the moisture and organic content of MSW, because they are important factors in the geotechnical characterization of MSW. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1231_s1?isAuthorized=no [article] Physical characterization of municipal solid waste for geotechnical purposes [texte imprimé] / Dimitrios Zekkos, Auteur ; Edward Jr Kavazanjian, Auteur ; Bray, Jonathan D., Auteur . - 2010 . - pp. 1231-1241. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1231-1241 Mots-clés : Municipal  solid  waste  Organic  content  Water  content  Waste  classification  Waste  Landfills  Geotechnical  characterization Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A procedure to characterize municipal solid waste (MSW) for geotechnical engineering purposes is developed based on experience with waste characterization and testing. Existing MSW classification systems are reviewed briefly, and the field and laboratory waste characterization programs of two important projects are presented. Findings on the influence of the waste’s physical composition on its mechanical response from these projects and recent studies of MSW are integrated to develop a waste characterization procedure for efficient collection of the relevant information on landfill operation and waste physical characteristics that are most likely to affect the geotechnical properties of MSW. A phased approach to implementation of this procedure is proposed as a best practice for the physical characterization of MSW for geotechnical purposes. The scope of the phased procedure can be adjusted to optimize the effort required to collect relevant information on a project-specific basis. The procedure includes a systematic evaluation of the moisture and organic content of MSW, because they are important factors in the geotechnical characterization of MSW. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1231_s1?isAuthorized=no

Method for estimating the deformability of heavily jointed rock masses / Lianyang Zhang in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1242-1250 Titre : Method for estimating the deformability of heavily jointed rock masses Type de document : texte imprimé Auteurs : Lianyang Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 1242-1250 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Jointed  rock  mass  Deformability  Equivalent  continuum  Analytical  expression Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Determination of the deformability of jointed rock masses is an important and challenging task in rock mechanics and rock engineering. In this paper, simple expressions are derived for estimating the equivalent isotropic deformation properties of heavily jointed rock masses using the methodology of equivalent continuum approach. The derived expressions are compared with two analytical relations in the literature and the field test data relating rock quality designation (RQD) and deformation modulus ratio Em/Er, where Em and Er are the deformation modulus of the rock mass and the intact rock, respectively. The derived expressions are in reasonable agreement with the existing analytical relations in the literature and satisfactorily predict the range of the field RQD versus modulus ratio Em/Er data. Finally two examples are presented to demonstrate the application of the derived expressions by applying them to estimate the deformation modulus of jointed rock mass at two sites. The results of the paper can be of help in predicting the deformation behavior of jointed rock masses when the properties of the intact rock and discontinuities are available. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1242_s1?isAuthorized=no [article] Method for estimating the deformability of heavily jointed rock masses [texte imprimé] / Lianyang Zhang, Auteur . - 2010 . - pp. 1242-1250. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1242-1250 Mots-clés : Jointed  rock  mass  Deformability  Equivalent  continuum  Analytical  expression Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Determination of the deformability of jointed rock masses is an important and challenging task in rock mechanics and rock engineering. In this paper, simple expressions are derived for estimating the equivalent isotropic deformation properties of heavily jointed rock masses using the methodology of equivalent continuum approach. The derived expressions are compared with two analytical relations in the literature and the field test data relating rock quality designation (RQD) and deformation modulus ratio Em/Er, where Em and Er are the deformation modulus of the rock mass and the intact rock, respectively. The derived expressions are in reasonable agreement with the existing analytical relations in the literature and satisfactorily predict the range of the field RQD versus modulus ratio Em/Er data. Finally two examples are presented to demonstrate the application of the derived expressions by applying them to estimate the deformation modulus of jointed rock mass at two sites. The results of the paper can be of help in predicting the deformation behavior of jointed rock masses when the properties of the intact rock and discontinuities are available. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1242_s1?isAuthorized=no

State boundary surfaces for an aged compacted clay / Abraham C. F. Chiu in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1251-1262 Titre : State boundary surfaces for an aged compacted clay Type de document : texte imprimé Auteurs : Abraham C. F. Chiu, Auteur ; X. Zhao, Auteur ; J. P. Yuan, Auteur Année de publication : 2010 Article en page(s) : pp. 1251-1262 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Clays  Laboratory  tests  Suction  Structures  Unsaturated  soils Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : The yielding and the peak strength of an aged compacted clay were studied by conducting a series of suction-controlled triaxial tests. The test results were interpreted using the framework of intrinsic properties of reconstituted soil. The peak strength envelopes of undisturbed samples lie above those of reconstituted samples. The suction provides additional attractive forces to stabilize the soil structure, which result in the augmentation of the yield stress and peak strength envelope. The shear strength is normalized by the equivalent preconsolidation pressure (pe′) and Hvorslev surfaces are identified from undisturbed samples which expand with suction. A single peak strength envelope and Hvorslev surface will be emerged from the saturated and unsaturated (degree of saturation >80%) samples if the shear strength data are presented in terms of the average skeleton stress. The influence of the soil structure on the shear strength of the aged compacted clay may be measured by the ratio of normalized strengths at the intrinsic critical state which is about 1.26 DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1251_s1?isAuthorized=no [article] State boundary surfaces for an aged compacted clay [texte imprimé] / Abraham C. F. Chiu, Auteur ; X. Zhao, Auteur ; J. P. Yuan, Auteur . - 2010 . - pp. 1251-1262. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1251-1262 Mots-clés : Clays  Laboratory  tests  Suction  Structures  Unsaturated  soils Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : The yielding and the peak strength of an aged compacted clay were studied by conducting a series of suction-controlled triaxial tests. The test results were interpreted using the framework of intrinsic properties of reconstituted soil. The peak strength envelopes of undisturbed samples lie above those of reconstituted samples. The suction provides additional attractive forces to stabilize the soil structure, which result in the augmentation of the yield stress and peak strength envelope. The shear strength is normalized by the equivalent preconsolidation pressure (pe′) and Hvorslev surfaces are identified from undisturbed samples which expand with suction. A single peak strength envelope and Hvorslev surface will be emerged from the saturated and unsaturated (degree of saturation >80%) samples if the shear strength data are presented in terms of the average skeleton stress. The influence of the soil structure on the shear strength of the aged compacted clay may be measured by the ratio of normalized strengths at the intrinsic critical state which is about 1.26 DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1251_s1?isAuthorized=no

Effect of sand columns on the undrained load response of soft clays / Shadi S. Najjar in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1263-1277 Titre : Effect of sand columns on the undrained load response of soft clays Type de document : texte imprimé Auteurs : Shadi S. Najjar, Auteur ; Salah Sadek, Auteur ; Tarek Maakaroun, Auteur Année de publication : 2010 Article en page(s) : pp. 1263-1277 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Ground  improvement  Stone  columns  Sand  drains  Geotextiles Résumé : When sand columns are used as vertical drains in soil improvement schemes, the possible reinforcing role that these columns can play in regards to improving the bearing capacity is usually neglected in design. The objective of this paper is to evaluate the degree of improvement in the mechanical properties of soft clays in practical applications involving the use of sand drains or sand columns in clayey soils. For this purpose, 32 isotropically consolidated undrained triaxial tests were performed on normally consolidated kaolin specimens. The parameters that were varied were the diameter of the sand columns, the height of the columns, the type of columns (geotextile encased versus nonencased), and the effective confining pressure. Test results indicated that sand columns improved the undrained strength significantly even for area replacement ratios that were less than 18%. The increase in undrained strength was accompanied by a decrease in pore pressure generation during shear and an increase in Young’s modulus. The drained shear strength parameters were found to be relatively unaffected by the sand column reinforcement, except for fully penetrating columns with high area replacement ratios. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1263_s1?isAuthorized=no [article] Effect of sand columns on the undrained load response of soft clays [texte imprimé] / Shadi S. Najjar, Auteur ; Salah Sadek, Auteur ; Tarek Maakaroun, Auteur . - 2010 . - pp. 1263-1277. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1263-1277 Mots-clés : Ground  improvement  Stone  columns  Sand  drains  Geotextiles Résumé : When sand columns are used as vertical drains in soil improvement schemes, the possible reinforcing role that these columns can play in regards to improving the bearing capacity is usually neglected in design. The objective of this paper is to evaluate the degree of improvement in the mechanical properties of soft clays in practical applications involving the use of sand drains or sand columns in clayey soils. For this purpose, 32 isotropically consolidated undrained triaxial tests were performed on normally consolidated kaolin specimens. The parameters that were varied were the diameter of the sand columns, the height of the columns, the type of columns (geotextile encased versus nonencased), and the effective confining pressure. Test results indicated that sand columns improved the undrained strength significantly even for area replacement ratios that were less than 18%. The increase in undrained strength was accompanied by a decrease in pore pressure generation during shear and an increase in Young’s modulus. The drained shear strength parameters were found to be relatively unaffected by the sand column reinforcement, except for fully penetrating columns with high area replacement ratios. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1263_s1?isAuthorized=no

Flow pattern for a silo with two layers of materials with single or double openings / Y. M. Cheng in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1278-1286 Titre : Flow pattern for a silo with two layers of materials with single or double openings Type de document : texte imprimé Auteurs : Y. M. Cheng, Auteur ; Chau, K. T., Auteur ; L. J. Xiao, Auteur Année de publication : 2010 Article en page(s) : pp. 1278-1286 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Silo  Particle  flow  Discharging  Openings  Numerical  simulation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : For the silo flow of two materials with contrasting strengths, an automatic separation without mixing of the materials is observed during drawing. In the present paper, the writers observe that a columniform funnel flow will appear in a silo with a single opening while a uniform flow will occur for a silo with a double opening. The classical and popular Janssen equation is hence less suitable for a silo with a single opening than for a silo with a double opening. The development of the arch action arising from the contact force is investigated through the distinct element analysis for the two different types of silo. It is also found that there are significant differences in the velocity and stress fields between the two different types of silo, which are worth consideration in the design of the silo and the recovery of the mineral ore. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1278_s1?isAuthorized=no [article] Flow pattern for a silo with two layers of materials with single or double openings [texte imprimé] / Y. M. Cheng, Auteur ; Chau, K. T., Auteur ; L. J. Xiao, Auteur . - 2010 . - pp. 1278-1286. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1278-1286 Mots-clés : Silo  Particle  flow  Discharging  Openings  Numerical  simulation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : For the silo flow of two materials with contrasting strengths, an automatic separation without mixing of the materials is observed during drawing. In the present paper, the writers observe that a columniform funnel flow will appear in a silo with a single opening while a uniform flow will occur for a silo with a double opening. The classical and popular Janssen equation is hence less suitable for a silo with a single opening than for a silo with a double opening. The development of the arch action arising from the contact force is investigated through the distinct element analysis for the two different types of silo. It is also found that there are significant differences in the velocity and stress fields between the two different types of silo, which are worth consideration in the design of the silo and the recovery of the mineral ore. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1278_s1?isAuthorized=no

Numerical study of the effect of verification core hole on the point bearing capacity of drilled shafts / Heejung Youn in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1287-1297 Titre : Numerical study of the effect of verification core hole on the point bearing capacity of drilled shafts Type de document : texte imprimé Auteurs : Heejung Youn, Auteur ; Tonon, Fulvio, Auteur Année de publication : 2010 Article en page(s) : pp. 1287-1297 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Verification  core  hole  Drying-duration  Numerical  analysis  Drilled  shafts  Clay  shales  Point  bearing  capacity  Degradation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents a numerical investigation of the effect of a verification core hole on the point bearing capacity of drilled shafts installed in clay shales. The verification core extracted at the shaft tip may reduce the point bearing capacity of drilled shafts as a result of degradation of clay shales and imperfect core hole infill. Finite-element analyses were conducted using the Mohr-Coulomb model with total stress material parameters estimated from laboratory tests. A series of load-displacement curves was calculated for 1 cycle of air drying and wetting; different drying durations and different core hole conditions were considered; and the point bearing capacity was determined at 3 and 5% shaft diameter displacements. The numerical analyses indicate that the point bearing capacity of drilled shafts with a verification core hole does not decrease for most cases, and the maximum reduction merely reaches 5%. Recommendations are made to reduce the effect of the verification core extracted at the shaft bottom during construction. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1287_s1?isAuthorized=no [article] Numerical study of the effect of verification core hole on the point bearing capacity of drilled shafts [texte imprimé] / Heejung Youn, Auteur ; Tonon, Fulvio, Auteur . - 2010 . - pp. 1287-1297. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1287-1297 Mots-clés : Verification  core  hole  Drying-duration  Numerical  analysis  Drilled  shafts  Clay  shales  Point  bearing  capacity  Degradation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents a numerical investigation of the effect of a verification core hole on the point bearing capacity of drilled shafts installed in clay shales. The verification core extracted at the shaft tip may reduce the point bearing capacity of drilled shafts as a result of degradation of clay shales and imperfect core hole infill. Finite-element analyses were conducted using the Mohr-Coulomb model with total stress material parameters estimated from laboratory tests. A series of load-displacement curves was calculated for 1 cycle of air drying and wetting; different drying durations and different core hole conditions were considered; and the point bearing capacity was determined at 3 and 5% shaft diameter displacements. The numerical analyses indicate that the point bearing capacity of drilled shafts with a verification core hole does not decrease for most cases, and the maximum reduction merely reaches 5%. Recommendations are made to reduce the effect of the verification core extracted at the shaft bottom during construction. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1287_s1?isAuthorized=no

Shear-wave velocity correlations for puyallup river alluvium / Armin W. Stuedlein in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1298-1304 Titre : Shear-wave velocity correlations for puyallup river alluvium Type de document : texte imprimé Auteurs : Armin W. Stuedlein, Auteur Année de publication : 2010 Article en page(s) : pp. 1298-1304 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Shear  waves  Velocity  Reliability  Correlations  Regressions Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : The suitability of selected cone penetration test-based shear-wave velocity correlations is assessed for use with Puyallup River alluvium in Puget Sound, Washington. The correlation models are found to be biased for Puyallup River alluvium; however, the functional forms of selected correlations were found to be readily adapted to local site conditions. The calibration for Puyallup River alluvium is presented and is found to perform satisfactorily for both down-hole SCPTu- and boring-based down-hole shear-wave velocity derived measurements. The distributions of prediction bias are presented for use in reliability studies. Recommendations are made for calibration of geologic-specific correlations using the functional forms of selected statistical shear-wave velocity regression models. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1298_s1?isAuthorized=no [article] Shear-wave velocity correlations for puyallup river alluvium [texte imprimé] / Armin W. Stuedlein, Auteur . - 2010 . - pp. 1298-1304. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1298-1304 Mots-clés : Shear  waves  Velocity  Reliability  Correlations  Regressions Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : The suitability of selected cone penetration test-based shear-wave velocity correlations is assessed for use with Puyallup River alluvium in Puget Sound, Washington. The correlation models are found to be biased for Puyallup River alluvium; however, the functional forms of selected correlations were found to be readily adapted to local site conditions. The calibration for Puyallup River alluvium is presented and is found to perform satisfactorily for both down-hole SCPTu- and boring-based down-hole shear-wave velocity derived measurements. The distributions of prediction bias are presented for use in reliability studies. Recommendations are made for calibration of geologic-specific correlations using the functional forms of selected statistical shear-wave velocity regression models. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1298_s1?isAuthorized=no

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