Dépouillements

Analysis of factors influencing soil classification using normalized piezocone tip resistance and pore pressure parameters / James A. Schneider in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1569–1586 Titre : Analysis of factors influencing soil classification using normalized piezocone tip resistance and pore pressure parameters Type de document : texte imprimé Auteurs : James A. Schneider, Auteur ; Mark F. Randolph, Auteur ; Paul W. Mayne, Auteur Année de publication : 2009 Article en page(s) : pp. 1569–1586 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil  classification  Cone  penetration  tests  Silts  Clays  Overconsolidated  soils Résumé : This paper discusses the development of a framework for classifying soil using normalized piezocone test (CPTU) data from the corrected tip resistance (qt) and penetration pore-water pressure at the shoulder (u2) . Parametric studies for normalized cone tip resistance (Q=qcnet/σ′v0) and normalized excess pressures (Δu2/σ′v0) as a function of overconsolidation ratio (OCR=σ′vy/σ′v0) during undrained penetration are combined with piezocone data from clay sites, as well as results from relatively uniform thick deposits of sands, silts, and varietal clays from around the globe. The study focuses on separating the influence of yield stress ratio from that of partial consolidation on normalized CPTU parameters, which both tend to increase Q and decrease the pore pressure parameter (Bq=Δu2/qcnet) . The resulting recommended classification chart is significantly different from existing charts, and implies that assessment of data in Q–Δu2/σ′v0 space is superior to Q–Bq space when evaluating piezocone data for a range of soil types. Still, there are zones of overlap for silty soils and heavily overconsolidated clays, thus requiring that supplementary information to Q and Δu2/σ′v0 be obtained in unfamiliar geologies, including variable rate penetration tests, dissipation tests, CPT friction ratio, or soil sampling. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Analysis of factors influencing soil classification using normalized piezocone tip resistance and pore pressure parameters [texte imprimé] / James A. Schneider, Auteur ; Mark F. Randolph, Auteur ; Paul W. Mayne, Auteur . - 2009 . - pp. 1569–1586. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1569–1586 Mots-clés : Soil  classification  Cone  penetration  tests  Silts  Clays  Overconsolidated  soils Résumé : This paper discusses the development of a framework for classifying soil using normalized piezocone test (CPTU) data from the corrected tip resistance (qt) and penetration pore-water pressure at the shoulder (u2) . Parametric studies for normalized cone tip resistance (Q=qcnet/σ′v0) and normalized excess pressures (Δu2/σ′v0) as a function of overconsolidation ratio (OCR=σ′vy/σ′v0) during undrained penetration are combined with piezocone data from clay sites, as well as results from relatively uniform thick deposits of sands, silts, and varietal clays from around the globe. The study focuses on separating the influence of yield stress ratio from that of partial consolidation on normalized CPTU parameters, which both tend to increase Q and decrease the pore pressure parameter (Bq=Δu2/qcnet) . The resulting recommended classification chart is significantly different from existing charts, and implies that assessment of data in Q–Δu2/σ′v0 space is superior to Q–Bq space when evaluating piezocone data for a range of soil types. Still, there are zones of overlap for silty soils and heavily overconsolidated clays, thus requiring that supplementary information to Q and Δu2/σ′v0 be obtained in unfamiliar geologies, including variable rate penetration tests, dissipation tests, CPT friction ratio, or soil sampling. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Reliability index for serviceability limit state of building foundations / Yu Wang in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1587–1594 Titre : Reliability index for serviceability limit state of building foundations Type de document : texte imprimé Auteurs : Yu Wang, Auteur ; Fred H. Kulhawy, Auteur Année de publication : 2009 Article en page(s) : pp. 1587–1594 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Reliability  Serviceability  Limit  states  foundations  Cast  in  place  Piles Résumé : Extensive research has been conducted on reliability-based design (RBD) for the ultimate limit state (ULS). Several RBD codes have been developed and implemented around the world that calibrate the ULS design for a target ULS reliability index (βuls) . However, the serviceability limit-state (SLS) design still is considered using conventional deterministic approaches with an unknown SLS reliability index (βsls) . This paper presents a relationship between βsls and the βuls that is specified already in the RBD codes. This relationship is linear, and a key variable in it is the ratio (R) of the SLS capacity (Qsls) to the ULS capacity (Quls) . Both closed-form approximations and Monte Carlo simulations are used to characterize R probabilistically. For illustration, the relationship then is used to estimate βsls for augered cast-in-place piles designed in accordance with the RBD methodologies in the National Building Code of Canada. The results are highly dependent on the statistics of the limiting tolerable foundation settlement (ylt) . For larger ylt values, the calculated βsls>βuls , which means that ULS designs automatically satisfy SLS criteria. For smaller ylt values, SLS criteria begin to control the design. The importance of sound ylt criteria is stressed. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Reliability index for serviceability limit state of building foundations [texte imprimé] / Yu Wang, Auteur ; Fred H. Kulhawy, Auteur . - 2009 . - pp. 1587–1594. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1587–1594 Mots-clés : Reliability  Serviceability  Limit  states  foundations  Cast  in  place  Piles Résumé : Extensive research has been conducted on reliability-based design (RBD) for the ultimate limit state (ULS). Several RBD codes have been developed and implemented around the world that calibrate the ULS design for a target ULS reliability index (βuls) . However, the serviceability limit-state (SLS) design still is considered using conventional deterministic approaches with an unknown SLS reliability index (βsls) . This paper presents a relationship between βsls and the βuls that is specified already in the RBD codes. This relationship is linear, and a key variable in it is the ratio (R) of the SLS capacity (Qsls) to the ULS capacity (Quls) . Both closed-form approximations and Monte Carlo simulations are used to characterize R probabilistically. For illustration, the relationship then is used to estimate βsls for augered cast-in-place piles designed in accordance with the RBD methodologies in the National Building Code of Canada. The results are highly dependent on the statistics of the limiting tolerable foundation settlement (ylt) . For larger ylt values, the calculated βsls>βuls , which means that ULS designs automatically satisfy SLS criteria. For smaller ylt values, SLS criteria begin to control the design. The importance of sound ylt criteria is stressed. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Cyclic softening of low-plasticity clay and its effect on seismic foundation performance / Daniel B. Chu in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1595–1608 Titre : Cyclic softening of low-plasticity clay and its effect on seismic foundation performance Type de document : texte imprimé Auteurs : Daniel B. Chu, Auteur ; Stewart, Jonathan P., Auteur ; Ross W. Boulanger, Auteur Année de publication : 2009 Article en page(s) : pp. 1595–1608 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil  liquefaction  Seismic  effects  Soil  structure  interaction  Shallow  foundations  In  situ  tests  Taiwan  Earthquakes Résumé : During the 1999 Chi-Chi Earthquake (Mw=7.6) , significant incidents of ground failure occurred in Wufeng, Taiwan, which experienced peak accelerations ∼0.7g . This paper describes the results of field investigations and analyses of a small region within Wufeng along an E–W trending line 350m long. The east end of the line has single-story structures for which there was no evidence of ground failure. The west end of the line had three to six-story reinforced concrete structures that underwent differential settlement and foundation bearing failures. No ground failure was observed in the free field. Surficial soils consist of low-plasticity silty clays that extend to 8–12m depth in the damaged area (west side), and 3–10m depth in the undamaged area (east side). A significant fraction of the foundation soils at the site are liquefaction susceptible based on several recently proposed criteria, but the site performance cannot be explained by analysis in existing liquefaction frameworks. Accordingly, an alternative approach is used that accounts for the clayey nature of the foundation soils. Field and laboratory tests are used to evaluate the monotonic and cyclic shear resistance of the soil, which is compared to the cyclic demand placed on the soil by ground response and soil–structure interaction. Results of the analysis indicate a potential for cyclic softening and associated strength loss in foundation soils below the six-story buildings, which contributes to bearing capacity failures at the edges of the foundation. Similar analyses indicate high factors of safety in foundation soils below one-story buildings as well in the free field, which is consistent with the observed field performance. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Cyclic softening of low-plasticity clay and its effect on seismic foundation performance [texte imprimé] / Daniel B. Chu, Auteur ; Stewart, Jonathan P., Auteur ; Ross W. Boulanger, Auteur . - 2009 . - pp. 1595–1608. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1595–1608 Mots-clés : Soil  liquefaction  Seismic  effects  Soil  structure  interaction  Shallow  foundations  In  situ  tests  Taiwan  Earthquakes Résumé : During the 1999 Chi-Chi Earthquake (Mw=7.6) , significant incidents of ground failure occurred in Wufeng, Taiwan, which experienced peak accelerations ∼0.7g . This paper describes the results of field investigations and analyses of a small region within Wufeng along an E–W trending line 350m long. The east end of the line has single-story structures for which there was no evidence of ground failure. The west end of the line had three to six-story reinforced concrete structures that underwent differential settlement and foundation bearing failures. No ground failure was observed in the free field. Surficial soils consist of low-plasticity silty clays that extend to 8–12m depth in the damaged area (west side), and 3–10m depth in the undamaged area (east side). A significant fraction of the foundation soils at the site are liquefaction susceptible based on several recently proposed criteria, but the site performance cannot be explained by analysis in existing liquefaction frameworks. Accordingly, an alternative approach is used that accounts for the clayey nature of the foundation soils. Field and laboratory tests are used to evaluate the monotonic and cyclic shear resistance of the soil, which is compared to the cyclic demand placed on the soil by ground response and soil–structure interaction. Results of the analysis indicate a potential for cyclic softening and associated strength loss in foundation soils below the six-story buildings, which contributes to bearing capacity failures at the edges of the foundation. Similar analyses indicate high factors of safety in foundation soils below one-story buildings as well in the free field, which is consistent with the observed field performance. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Liquefaction-induced settlement of pile groups in liquefiable and laterally spreading soils / J. A. Knappett in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1609–1618 Titre : Liquefaction-induced settlement of pile groups in liquefiable and laterally spreading soils Type de document : texte imprimé Auteurs : J. A. Knappett, Auteur ; S. P. Madabhushi, Auteur Année de publication : 2009 Article en page(s) : pp. 1609–1618 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Earthquake  engineering  Liquefaction  Pile  groups  Pile  settlement  Lateral  displacement  Centrifuge  model  Seismic  design Résumé : The results of a series of dynamic centrifuge tests on model pile groups in (level) liquefied and laterally spreading soil profiles are presented. The piles are axially loaded at typical working loads, which has enabled liquefaction-induced settlements of the foundations to be studied. The development of excess pore pressures within the bearing layer (dense sand) was found to lead to a reduction in pile capacity and potentially damagingly large coseismic settlements. As the excess pore pressure increased, these settlements were observed to exceed postshaking downdrag-induced settlements, which occur due to the reconsolidation of liquefied sand around the pile shaft. In resisting settlement, the pile cap was found to play an important role by compensating for the capacity lost by the piles. This was shown to be achieved by the development of dilative excess pore pressures beneath the pile cap within the underlying loose liquefied sand which provide increasing bearing capacity with settlement. The centrifuge test data show good qualitative and quantitative agreement with the limited amount of model and full-scale data currently available in the literature. The implications of settlement for the design of piled foundations to serviceability conditions in both level and sloping ground are discussed, with settlement becoming an increasingly important consideration for laterally stiffer piles. Finally, empirical relationships have been derived from the test data to relate suitable static safety factors to given increases in excess pore pressure in the bearing layer within a performance-based design framework (i.e., based on limiting displacements). En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Liquefaction-induced settlement of pile groups in liquefiable and laterally spreading soils [texte imprimé] / J. A. Knappett, Auteur ; S. P. Madabhushi, Auteur . - 2009 . - pp. 1609–1618. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1609–1618 Mots-clés : Earthquake  engineering  Liquefaction  Pile  groups  Pile  settlement  Lateral  displacement  Centrifuge  model  Seismic  design Résumé : The results of a series of dynamic centrifuge tests on model pile groups in (level) liquefied and laterally spreading soil profiles are presented. The piles are axially loaded at typical working loads, which has enabled liquefaction-induced settlements of the foundations to be studied. The development of excess pore pressures within the bearing layer (dense sand) was found to lead to a reduction in pile capacity and potentially damagingly large coseismic settlements. As the excess pore pressure increased, these settlements were observed to exceed postshaking downdrag-induced settlements, which occur due to the reconsolidation of liquefied sand around the pile shaft. In resisting settlement, the pile cap was found to play an important role by compensating for the capacity lost by the piles. This was shown to be achieved by the development of dilative excess pore pressures beneath the pile cap within the underlying loose liquefied sand which provide increasing bearing capacity with settlement. The centrifuge test data show good qualitative and quantitative agreement with the limited amount of model and full-scale data currently available in the literature. The implications of settlement for the design of piled foundations to serviceability conditions in both level and sloping ground are discussed, with settlement becoming an increasingly important consideration for laterally stiffer piles. Finally, empirical relationships have been derived from the test data to relate suitable static safety factors to given increases in excess pore pressure in the bearing layer within a performance-based design framework (i.e., based on limiting displacements). En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Liquefaction-induced settlement of pile groups in liquefiable and laterally spreading soils / J. A. Knappett in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1609–1618 Titre : Liquefaction-induced settlement of pile groups in liquefiable and laterally spreading soils Type de document : texte imprimé Auteurs : J. A. Knappett, Auteur ; S. P. Madabhushi, Auteur Année de publication : 2009 Article en page(s) : pp. 1609–1618 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Earthquake  engineering  Liquefaction  Pile  groups  Pile  settlement  Lateral  displacement  Centrifuge  model  Seismic  design Résumé : The results of a series of dynamic centrifuge tests on model pile groups in (level) liquefied and laterally spreading soil profiles are presented. The piles are axially loaded at typical working loads, which has enabled liquefaction-induced settlements of the foundations to be studied. The development of excess pore pressures within the bearing layer (dense sand) was found to lead to a reduction in pile capacity and potentially damagingly large coseismic settlements. As the excess pore pressure increased, these settlements were observed to exceed postshaking downdrag-induced settlements, which occur due to the reconsolidation of liquefied sand around the pile shaft. In resisting settlement, the pile cap was found to play an important role by compensating for the capacity lost by the piles. This was shown to be achieved by the development of dilative excess pore pressures beneath the pile cap within the underlying loose liquefied sand which provide increasing bearing capacity with settlement. The centrifuge test data show good qualitative and quantitative agreement with the limited amount of model and full-scale data currently available in the literature. The implications of settlement for the design of piled foundations to serviceability conditions in both level and sloping ground are discussed, with settlement becoming an increasingly important consideration for laterally stiffer piles. Finally, empirical relationships have been derived from the test data to relate suitable static safety factors to given increases in excess pore pressure in the bearing layer within a performance-based design framework (i.e., based on limiting displacements). En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Liquefaction-induced settlement of pile groups in liquefiable and laterally spreading soils [texte imprimé] / J. A. Knappett, Auteur ; S. P. Madabhushi, Auteur . - 2009 . - pp. 1609–1618. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1609–1618 Mots-clés : Earthquake  engineering  Liquefaction  Pile  groups  Pile  settlement  Lateral  displacement  Centrifuge  model  Seismic  design Résumé : The results of a series of dynamic centrifuge tests on model pile groups in (level) liquefied and laterally spreading soil profiles are presented. The piles are axially loaded at typical working loads, which has enabled liquefaction-induced settlements of the foundations to be studied. The development of excess pore pressures within the bearing layer (dense sand) was found to lead to a reduction in pile capacity and potentially damagingly large coseismic settlements. As the excess pore pressure increased, these settlements were observed to exceed postshaking downdrag-induced settlements, which occur due to the reconsolidation of liquefied sand around the pile shaft. In resisting settlement, the pile cap was found to play an important role by compensating for the capacity lost by the piles. This was shown to be achieved by the development of dilative excess pore pressures beneath the pile cap within the underlying loose liquefied sand which provide increasing bearing capacity with settlement. The centrifuge test data show good qualitative and quantitative agreement with the limited amount of model and full-scale data currently available in the literature. The implications of settlement for the design of piled foundations to serviceability conditions in both level and sloping ground are discussed, with settlement becoming an increasingly important consideration for laterally stiffer piles. Finally, empirical relationships have been derived from the test data to relate suitable static safety factors to given increases in excess pore pressure in the bearing layer within a performance-based design framework (i.e., based on limiting displacements). En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Shear strength and shear-induced volume change behavior of unsaturated soils from a triaxial test program / Sandra L. Houston in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1619–1632 Titre : Shear strength and shear-induced volume change behavior of unsaturated soils from a triaxial test program Type de document : texte imprimé Auteurs : Sandra L. Houston, Auteur ; Natalia Perez-Garcia, Auteur ; William N. Houston, Auteur Année de publication : 2009 Article en page(s) : pp. 1619–1632 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Shear  strength  Suction  Volume  change  Unsaturated  soils  Triaxial  tests  Soil  properties Résumé : A series of unsaturated soil triaxial tests were performed on four soils including sand, silt, and a low plasticity clay. Attempts were made to correlate unsaturated soil properties from these tests and data from the literature with soil-water characteristics curve (SWCC), soil gradation, and saturated soil properties. The feasibility of estimating unsaturated soil property functions from saturated soil properties, SWCCs and gradation data, is demonstrated. A hyperbolic model for estimation of the unsaturated soil parameter, ϕb , versus matric suction is presented. Shear induced volume change behavior was also studied, and results are included in this paper. Although not correlated with soil index properties, these shear-induced volume change data are important to complete stress-deformation analyses, and represent a significant addition to the existing data base of unsaturated soil properties. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Shear strength and shear-induced volume change behavior of unsaturated soils from a triaxial test program [texte imprimé] / Sandra L. Houston, Auteur ; Natalia Perez-Garcia, Auteur ; William N. Houston, Auteur . - 2009 . - pp. 1619–1632. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1619–1632 Mots-clés : Shear  strength  Suction  Volume  change  Unsaturated  soils  Triaxial  tests  Soil  properties Résumé : A series of unsaturated soil triaxial tests were performed on four soils including sand, silt, and a low plasticity clay. Attempts were made to correlate unsaturated soil properties from these tests and data from the literature with soil-water characteristics curve (SWCC), soil gradation, and saturated soil properties. The feasibility of estimating unsaturated soil property functions from saturated soil properties, SWCCs and gradation data, is demonstrated. A hyperbolic model for estimation of the unsaturated soil parameter, ϕb , versus matric suction is presented. Shear induced volume change behavior was also studied, and results are included in this paper. Although not correlated with soil index properties, these shear-induced volume change data are important to complete stress-deformation analyses, and represent a significant addition to the existing data base of unsaturated soil properties. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Soil vibrations caused by underground moving trains / Y. B. Yang in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1633–1644 Titre : Soil vibrations caused by underground moving trains Type de document : texte imprimé Auteurs : Y. B. Yang, Auteur ; H. H. Hung, Auteur Année de publication : 2009 Article en page(s) : pp. 1633–1644 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Half  space  Finite  element  method  Railroad  trains  Wave  propagation  Vibration  Tunnels Résumé : The wave propagation problems caused by the underground moving trains are analyzed by the 2.5-dimensional finite/infinite-element approach. The near field of the half-space, including the tunnel and parts of the soil, is simulated by finite elements, and the far field extending to infinity by infinite elements. The train is simulated as a sequence of wheel loads moving at constant speeds. Using the present approach, a two-dimensional profile with three degrees per node is used to simulate the three-dimensional behavior of the half-space, which is valid for the case when the material and geometry of the system are invariant along the tunnel direction. The factors considered in the analysis of ground-borne vibrations include the damping ratio and stratum depth of the supporting soils, the depth and thickness of the tunnel, and the moving speed and excitation frequency of the trains. It was found that moving train loads with nonzero excitation frequencies can induce significantly higher vibrations than the static moving loads. The effect of stratum depth depends highly on the excitation frequency. For a tunnel constructed in a stiffer soil, the ground surface vibrations can be greatly reduced. Other conclusions useful to practical engineers are contained in the parametric study. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Soil vibrations caused by underground moving trains [texte imprimé] / Y. B. Yang, Auteur ; H. H. Hung, Auteur . - 2009 . - pp. 1633–1644. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1633–1644 Mots-clés : Half  space  Finite  element  method  Railroad  trains  Wave  propagation  Vibration  Tunnels Résumé : The wave propagation problems caused by the underground moving trains are analyzed by the 2.5-dimensional finite/infinite-element approach. The near field of the half-space, including the tunnel and parts of the soil, is simulated by finite elements, and the far field extending to infinity by infinite elements. The train is simulated as a sequence of wheel loads moving at constant speeds. Using the present approach, a two-dimensional profile with three degrees per node is used to simulate the three-dimensional behavior of the half-space, which is valid for the case when the material and geometry of the system are invariant along the tunnel direction. The factors considered in the analysis of ground-borne vibrations include the damping ratio and stratum depth of the supporting soils, the depth and thickness of the tunnel, and the moving speed and excitation frequency of the trains. It was found that moving train loads with nonzero excitation frequencies can induce significantly higher vibrations than the static moving loads. The effect of stratum depth depends highly on the excitation frequency. For a tunnel constructed in a stiffer soil, the ground surface vibrations can be greatly reduced. Other conclusions useful to practical engineers are contained in the parametric study. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Analysis of the deformation of embankments on the Qinghai-Tibet railway / Wei Ma in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1645–1654 Titre : Analysis of the deformation of embankments on the Qinghai-Tibet railway Type de document : texte imprimé Auteurs : Wei Ma, Auteur ; Jilin Qi, Auteur Année de publication : 2009 Article en page(s) : pp. 1645–1654 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Rail  transportation  Permafrost  Embankments  Deformation  Monitoring  China Résumé : Temperature changes and deformations were monitored on various embankment types on the Qinghai-Tibet Railway. Some of these embankments utilized permafrost protection techniques such as duct ventilation, crushed-rock embankments, crushed-rock protected slopes, or thermal-insulation treatments. Some embankments were built conventionally without considering permafrost protection. It was found that the majority of the deformations on both the permafrost-protected and the conventionally built embankments were due to deformation of warm frozen layers closely related to the temperature changes in the underlying permafrost. However, it was found that building embankments with permafrost protection reduced the magnitude of the settlements. After 2–3years , deformation of all the embankments with permafrost protection countermeasures became smaller and smaller, whereas deformation was still increasing in the conventional embankments, where the settlement in the underlying permafrost could reach a considerable level, and could be a potential trigger for embankment failure. This should be taken into consideration in the railway engineering project on the Qinghai-Tibet Plateau. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Analysis of the deformation of embankments on the Qinghai-Tibet railway [texte imprimé] / Wei Ma, Auteur ; Jilin Qi, Auteur . - 2009 . - pp. 1645–1654. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1645–1654 Mots-clés : Rail  transportation  Permafrost  Embankments  Deformation  Monitoring  China Résumé : Temperature changes and deformations were monitored on various embankment types on the Qinghai-Tibet Railway. Some of these embankments utilized permafrost protection techniques such as duct ventilation, crushed-rock embankments, crushed-rock protected slopes, or thermal-insulation treatments. Some embankments were built conventionally without considering permafrost protection. It was found that the majority of the deformations on both the permafrost-protected and the conventionally built embankments were due to deformation of warm frozen layers closely related to the temperature changes in the underlying permafrost. However, it was found that building embankments with permafrost protection reduced the magnitude of the settlements. After 2–3years , deformation of all the embankments with permafrost protection countermeasures became smaller and smaller, whereas deformation was still increasing in the conventional embankments, where the settlement in the underlying permafrost could reach a considerable level, and could be a potential trigger for embankment failure. This should be taken into consideration in the railway engineering project on the Qinghai-Tibet Plateau. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Thermal analysis of cover systems in municipal solid waste landfills / Nazli Yesiller in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1655–1664 Titre : Thermal analysis of cover systems in municipal solid waste landfills Type de document : texte imprimé Auteurs : Nazli Yesiller, Auteur ; James L. Hanson, Auteur ; Nicolas K. Oettle, Auteur Année de publication : 2009 Article en page(s) : pp. 1655–1664 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Temperature  effects  Landfills  Municipal  wastes  Solid  wastes  Geomembranes  Material  properties Résumé : Cover temperature variations were determined at four municipal solid waste landfills located in different climatic regions in North America: Michigan, New Mexico, Alaska, and British Columbia. Cover temperatures varied seasonally similarly to air temperatures and demonstrated amplitude decrement and phase lag with depth. Elevated temperatures in the underlying wastes resulted in warmer temperatures and low frost penetration in the covers compared to surrounding subgrade soils. The ranges of measured temperatures decreased and average temperatures generally increased (approximately 2°C∕m ) with depth. The ranges of measured temperatures (Tmax−Tmin) were 18–30°C and 13–21°C and the average temperatures were 13–18°C and 14–23°C at 1 and 2m depths, respectively. For soil and geosynthetic barrier materials around 1m depth, the maximum and minimum temperatures were 22–25°C and 3–4°C , respectively. Frost depths were determined to be approximately 50% of those for soils at ambient conditions. The main direction of heat flow in the covers was upward (negative gradients). The cover gradients varied between −18 and 14°C∕m , with averages of −7to1°C∕m . The gradients for soil and geosynthetic barrier materials around 1m depth varied between −11 and 9°C∕m with an average of −2°C∕m . Cover thawing n -factors ranged between 1.0 and 1.4 and the cover freezing n -factor was 0.6. Design charts and guidelines are provided for cover thermal analyses for variable climatic conditions. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Thermal analysis of cover systems in municipal solid waste landfills [texte imprimé] / Nazli Yesiller, Auteur ; James L. Hanson, Auteur ; Nicolas K. Oettle, Auteur . - 2009 . - pp. 1655–1664. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1655–1664 Mots-clés : Temperature  effects  Landfills  Municipal  wastes  Solid  wastes  Geomembranes  Material  properties Résumé : Cover temperature variations were determined at four municipal solid waste landfills located in different climatic regions in North America: Michigan, New Mexico, Alaska, and British Columbia. Cover temperatures varied seasonally similarly to air temperatures and demonstrated amplitude decrement and phase lag with depth. Elevated temperatures in the underlying wastes resulted in warmer temperatures and low frost penetration in the covers compared to surrounding subgrade soils. The ranges of measured temperatures decreased and average temperatures generally increased (approximately 2°C∕m ) with depth. The ranges of measured temperatures (Tmax−Tmin) were 18–30°C and 13–21°C and the average temperatures were 13–18°C and 14–23°C at 1 and 2m depths, respectively. For soil and geosynthetic barrier materials around 1m depth, the maximum and minimum temperatures were 22–25°C and 3–4°C , respectively. Frost depths were determined to be approximately 50% of those for soils at ambient conditions. The main direction of heat flow in the covers was upward (negative gradients). The cover gradients varied between −18 and 14°C∕m , with averages of −7to1°C∕m . The gradients for soil and geosynthetic barrier materials around 1m depth varied between −11 and 9°C∕m with an average of −2°C∕m . Cover thawing n -factors ranged between 1.0 and 1.4 and the cover freezing n -factor was 0.6. Design charts and guidelines are provided for cover thermal analyses for variable climatic conditions. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Crushed glass-dredged material (CG-DM) blends / Dennis G. Grubb in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1665–1675 Titre : Crushed glass-dredged material (CG-DM) blends : role of organic matter content and DM variability on field compaction Type de document : texte imprimé Auteurs : Dennis G. Grubb, Auteur ; Allen W. Cadden, Auteur ; David D. Miller, Auteur Année de publication : 2009 Article en page(s) : pp. 1665–1675 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Laboratory  tests  Recycling  Glass  Dredge  spoil  Physical  properties  Soil  mixing  Organic  matter  Field  tests  Soil  compaction Résumé : Trial embankments comprised of crushed glass-dredged material (CG-DM) blends and a 100% DM embankment were constructed to provide the necessary data sets to determine if a moisture content (MC) correction was required for the nuclear density (ND) gauge, as DM may contain a high organic matter content (OC). The MCs of thin-walled tube samples of CG-DM blends collected immediately below the ND gauge were compared to the corresponding ND gauge readings. A direct correlation between the MC data pairings from the tube samples and ND gauge readings showed that the ND gauge was greater than 97% accurate for MCs up to 55% and OCs up to 10% for the CG-DM blends evaluated in this study. However, the MC determined by the ND gauge was underpredicted (not overpredicted) by approximately 2.5%, contrary to theoretical expectations. A comparison of the average MC results per embankment indicated that the ND gauge was generally within 1% of the tube sample values, again on the low side. Interestingly, the rutting of the individual embankment lifts, often used as an informal metric for compaction compliance also was found to be contrary to expectations. The (re)constructed CG-DM embankments of this study were again shown to satisfy local Department of Transportation embankment construction criteria in most cases. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Crushed glass-dredged material (CG-DM) blends : role of organic matter content and DM variability on field compaction [texte imprimé] / Dennis G. Grubb, Auteur ; Allen W. Cadden, Auteur ; David D. Miller, Auteur . - 2009 . - pp. 1665–1675. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1665–1675 Mots-clés : Laboratory  tests  Recycling  Glass  Dredge  spoil  Physical  properties  Soil  mixing  Organic  matter  Field  tests  Soil  compaction Résumé : Trial embankments comprised of crushed glass-dredged material (CG-DM) blends and a 100% DM embankment were constructed to provide the necessary data sets to determine if a moisture content (MC) correction was required for the nuclear density (ND) gauge, as DM may contain a high organic matter content (OC). The MCs of thin-walled tube samples of CG-DM blends collected immediately below the ND gauge were compared to the corresponding ND gauge readings. A direct correlation between the MC data pairings from the tube samples and ND gauge readings showed that the ND gauge was greater than 97% accurate for MCs up to 55% and OCs up to 10% for the CG-DM blends evaluated in this study. However, the MC determined by the ND gauge was underpredicted (not overpredicted) by approximately 2.5%, contrary to theoretical expectations. A comparison of the average MC results per embankment indicated that the ND gauge was generally within 1% of the tube sample values, again on the low side. Interestingly, the rutting of the individual embankment lifts, often used as an informal metric for compaction compliance also was found to be contrary to expectations. The (re)constructed CG-DM embankments of this study were again shown to satisfy local Department of Transportation embankment construction criteria in most cases. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Aging of crushed glass-dredged material blend embankments / Dennis G. Grubb in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1676–1684 Titre : Aging of crushed glass-dredged material blend embankments Type de document : texte imprimé Auteurs : Dennis G. Grubb, Auteur ; Joseph Wartman, Auteur ; Nicholas E. Malasavage, Auteur Année de publication : 2009 Article en page(s) : pp. 1676–1684 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Laboratory  tests  Recycling  Glass  Dredge  spoil  Physical  properties  Aging  Penetrometers  Embankments Résumé : Four crushed glass (CG) and dredged material (DM) [(CG-DM)] blend embankments constructed (2004) and reconstructed (2005) to local DOT specifications were subjected to cone penetrometer tests (CPT). The CPT resistance of the original set of embankments was evaluated shortly after construction and approximately 360days later, immediately prior to being demolished for purposes of a second study. Cone tip resistances were observed to double to triple with aging. For the 80∕20 CG-DM blend, a 4MPa [40 tons per square foot (tsf)] or threefold increase in CPT tip resistance was measured. Likewise, isotropically consolidated, undrained triaxial shear tests were performed on relatively undisturbed thin-walled tube specimens of the 360-day aged CG-DM blend materials. The triaxial tests revealed that the effective friction angles of the aged materials increased by up to 8° over freshly prepared laboratory CG-DM blend specimens. The strength gains appeared to be more strongly linked to (amorphous) silica cementation rather than the formation of carbonates. Disturbance (demolition and reconstruction) generally reduced the in situ CPT behavior to that of the originally constructed embankments. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Aging of crushed glass-dredged material blend embankments [texte imprimé] / Dennis G. Grubb, Auteur ; Joseph Wartman, Auteur ; Nicholas E. Malasavage, Auteur . - 2009 . - pp. 1676–1684. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1676–1684 Mots-clés : Laboratory  tests  Recycling  Glass  Dredge  spoil  Physical  properties  Aging  Penetrometers  Embankments Résumé : Four crushed glass (CG) and dredged material (DM) [(CG-DM)] blend embankments constructed (2004) and reconstructed (2005) to local DOT specifications were subjected to cone penetrometer tests (CPT). The CPT resistance of the original set of embankments was evaluated shortly after construction and approximately 360days later, immediately prior to being demolished for purposes of a second study. Cone tip resistances were observed to double to triple with aging. For the 80∕20 CG-DM blend, a 4MPa [40 tons per square foot (tsf)] or threefold increase in CPT tip resistance was measured. Likewise, isotropically consolidated, undrained triaxial shear tests were performed on relatively undisturbed thin-walled tube specimens of the 360-day aged CG-DM blend materials. The triaxial tests revealed that the effective friction angles of the aged materials increased by up to 8° over freshly prepared laboratory CG-DM blend specimens. The strength gains appeared to be more strongly linked to (amorphous) silica cementation rather than the formation of carbonates. Disturbance (demolition and reconstruction) generally reduced the in situ CPT behavior to that of the originally constructed embankments. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

Note on the interaction factor for two laterally loaded piles / S. L. Chen in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°11 (Novembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1685–1690 Titre : Note on the interaction factor for two laterally loaded piles Type de document : texte imprimé Auteurs : S. L. Chen, Auteur ; L. Z. Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 1685–1690 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Piles  Lateral  loads  Bending  moments  Interactions Résumé : This technical note revisits the interaction factors for two piles under lateral loading by means of a rigorous analytical method. The basic idea of the approach presented is to decompose the problem into an extended elastic soil and two fictitious piles having Young’s modulus equal to the difference between the modulus of the real pile and the surrounding soil. By considering the displacement compatibility condition, the pile–soil interaction problem is found to be governed by a Fredholm equation of the second kind. The displacement and bending moment distribution along the fictitious piles, and consequently, the desired interaction factor at the pile head are obtained. Comparison with existing solutions validates the accuracy of the present formulation and confirms that the conventional interaction factor approach would exaggerate the interaction effect for long flexible piles. Some numerical examples are presented to illustrate the influences of the pile spacing, pile–soil stiffness ratio, pile slenderness ratio, and departure angle of the loading direction on the calculated results. A set of interaction factor charts is also provided. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...] [article] Note on the interaction factor for two laterally loaded piles [texte imprimé] / S. L. Chen, Auteur ; L. Z. Chen, Auteur . - 2009 . - pp. 1685–1690. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°11 (Novembre 2008) . - pp. 1685–1690 Mots-clés : Piles  Lateral  loads  Bending  moments  Interactions Résumé : This technical note revisits the interaction factors for two piles under lateral loading by means of a rigorous analytical method. The basic idea of the approach presented is to decompose the problem into an extended elastic soil and two fictitious piles having Young’s modulus equal to the difference between the modulus of the real pile and the surrounding soil. By considering the displacement compatibility condition, the pile–soil interaction problem is found to be governed by a Fredholm equation of the second kind. The displacement and bending moment distribution along the fictitious piles, and consequently, the desired interaction factor at the pile head are obtained. Comparison with existing solutions validates the accuracy of the present formulation and confirms that the conventional interaction factor approach would exaggerate the interaction effect for long flexible piles. Some numerical examples are presented to illustrate the influences of the pile spacing, pile–soil stiffness ratio, pile slenderness ratio, and departure angle of the loading direction on the calculated results. A set of interaction factor charts is also provided. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A11%281 [...]

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