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Papers by Harry Poulos

Research paper thumbnail of Probabilistic Applications in Geotechnical Engineering

Probabilistic Applications in Geotechnical Engineering, 2007

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Research paper thumbnail of Re-assessment of foundation settlements for the Burj Khalifa, Dubai

Acta Geotechnica, 2012

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Research paper thumbnail of Foundation Settlement Analysis. De Mello Volume; a Tribute to Professor Dr. Victor F. B. De Mello in Honor of His Contribution to the Development of Geotechnical Engineering in Latin America

Foundation settlements may arise from a number of causes, including: (i) static loads, such as th... more Foundation settlements may arise from a number of causes, including: (i) static loads, such as those imposed by the weight of the structure; (ii) dynamic, repeated or transient loads, such as those produced by machinery or environmental wind and wave loadings; and (iii) changes in moisture content, for example from seasonal fluctuation in the water table, rainfall and evaporation, or the absorption of water by the roots of large trees. The effects of nearby construction (for example excavation, pile driving and de-watering) may also be significant. In this paper attention is concentrated on settlements of saturated soils due to static loads, although many of the principles may be applied to settlements due to other causes, and it must be emphasized that settlements due to the latter two causes listed above may often be as significant as those due to static loads. This paper provides a brief general review of the principles of settlement analysis, and some of the methods available for carrying out settlement calculations. A brief review is also made of procedures for determining the required geotechnical parameters. For the covering abstract of this book see IRRD 836508. (TRRL)

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Research paper thumbnail of Pile behaviour — theory and application

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Apr 1, 1990

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Research paper thumbnail of Piles subjected to negative friction; a procedure for design

Geotechnical engineering, 1997

This paper emphasizes the fact that when piles are subjected to negative friction, their ultimate... more This paper emphasizes the fact that when piles are subjected to negative friction, their ultimate geotechnical capacity is not significantly influenced, and the main deleterious effects arise from increased settlement and an increased axial force in the pile, which can influence structural integrity. Hand and computer methods for estimating the settlement and maximum load in the pile are described. The hand method assumes full pile-soil slip and agrees well with the computer analysis when the free-field soil movements are relatively large. A simple design approach is developed for estimating the maximum load which can be applied to the head of a pile subjected to negative friction. This load is based on the condition that the pile head settlement should reach an acceptable limiting value, regardless of the settlement of the soil. An example of the application of the computer and hand methods is described, and it is demonstrated that bitumen coating of the piles can allow larger load...

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Research paper thumbnail of 2. Development of design charts for concrete pavements and industrial ground slabs

Design applications of raft foundations

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Research paper thumbnail of Static and Cyclic Direct Shear Tests on Carbonate Sands

Geotechnical Testing Journal, 1992

This paper examines the static and cyclic behavior of different types of carbonate sediments and ... more This paper examines the static and cyclic behavior of different types of carbonate sediments and one type of silica sand under direct shear test conditions. For both static and cyclic loading, the effects of interface surface roughness, overburden pressure, void ratio, size and shape of grains, and saturation are studied. It is found that the static shear resistance is influenced by most of these factors and that the cyclic behavior depends significantly on the number of cycles and the cyclic displacement amplitude. The amount of crushing caused by cyclic loading is found to depend strongly on particle shape and grading characteristics.

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Research paper thumbnail of Estimation of Pile Friction Degradation from Shearbox Tests

Geotechnical Testing Journal, 1992

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Research paper thumbnail of Behaviour of Pile Groups in Liquefying Soil

This paper presents a simplified method of analysis for pile groups founded in liquefying soil. T... more This paper presents a simplified method of analysis for pile groups founded in liquefying soil. The method involves two main steps. First an effective stress based ground response analysis is carried out to obtain the maximum ground displacements along the pile and the degraded soil modulus over the depth of soil deposit. Next a dynamic analysis is carried out for a single pile in the group assuming that each pile in the group behaves in the same way during the earthquake loading. The method has been verified using centrifuge data, where soil liquefaction has been observed in laterally spreading ground. It is demonstrated that the new method gives good estimate of pile behaviour, despite its relative simplicity

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Research paper thumbnail of A review of geological and geotechnical features of some Middle Eastern countries

Innovative Infrastructure Solutions, May 30, 2018

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Research paper thumbnail of Design for ground movements

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Research paper thumbnail of The Warren Centre underground space project

Pages, Jun 7, 1996

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Research paper thumbnail of From theory to practice in pile design

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Mar 1, 1989

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Research paper thumbnail of A systematic approach to forensic foundation engineering

Proceedings of the Institution of Civil Engineers, May 1, 2009

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Research paper thumbnail of Design Method for Stabilization of Slopes with Piles. Discussions and Closure

Journal of Geotechnical and Geoenvironmental Engineering, Oct 1, 1999

ABSTRACT A methodology is proposed for the design of slopes reinforced with a single row of piles... more ABSTRACT A methodology is proposed for the design of slopes reinforced with a single row of piles. An existing method which is based on the theory of plasticity is used to find the lateral forces acting on the pile section above the critical surface. A portion of that force is assumed to be mobilized against the movement of the slope. Then, the friction circle method is extended to incorporate the reaction force in the stability analysis. Thus a new stability number that includes the pile reaction is used to determine the modified critical surface and safety factor of the reinforced slope. Finally, a procedure is proposed to achieve an optimum design solution which provides a desirable factor of safety for the slope/pile system.

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Research paper thumbnail of Closure to “Numerical Modeling of Geotextile-Reinforced Embankments over Deep Cement Mixed Columns Incorporating Strain-Softening Behavior of Columns” by N. N. S. Yapage, D. S. Liyanapathirana, H. G. Poulos, R. B. Kelly, and C. J. Leo

International Journal of Geomechanics, Aug 1, 2015

The writers thank the discussers for their interest and the important points raised by them perta... more The writers thank the discussers for their interest and the important points raised by them pertaining to the original paper. The main aim of the original paper was to demonstrate the application of the extended version of the Mohr-Coulomb model for the simulation of the strain-softening behavior of cement-stabilized soils. The writers validated the model using triaxial data, and then applied it to a case study in which both isolated and attached columns were used, to show the capability of the model in predicting the embankment behavior. Finally, the proposed model was used to demonstrate the progressive failure of a hypothetical embankment with isolated columns in a square pattern

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Research paper thumbnail of Tests on Model Instrumented Piles in Calcareous Soil

The annual research report, Apr 1, 1988

This paper describes the results of tests on model piles jacked into beds of reconstituted marine... more This paper describes the results of tests on model piles jacked into beds of reconstituted marine calcareous sediments. The behaviour of a single pile is examined during installation, under static loading and under cyclic loading (both load controlled and displacement controlled). It is found that significant residual stresses exist in the pile after installation. A low skin friction is developed along the pile shaft, primarily due to the reduction of lateral stress which appears to occur during installation of the pile. Cyclic loading generally leads to a further reduction in skin friction, this reduction being a function of the cyclic displacement which the pile undergoes, rather than the cyclic load level. Comparisons are also made with the data obtained from previous tests on small model piles installed into the soil prior to consolidation of the soil bed. These comparisons show the importance of the in situ lateral stress on the skin friction developed under static loading, but suggest that cyclic degradation is not seriously influenced by this factor (a).

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Research paper thumbnail of Field study of pile – prefabricated vertical drain (PVD) interaction in soft clay

Canadian Geotechnical Journal, Mar 1, 2020

Piles and prefabricated vertical drains (PVDs) are two well-established inclusions used by geotec... more Piles and prefabricated vertical drains (PVDs) are two well-established inclusions used by geotechnical practitioners when dealing with soft compressible foundations. Induced movements in highly compressible soil can adversely influence the pile response by inducing additional movements and stresses in the piles. Especially, undesirable soil–pile interaction often leads to the development of excess pore-water pressure during pile installation and negative skin friction caused by the settlement of compressible soil surrounding the piles. Additional drainage by PVDs prior to the installation of a pile could reduce excess pore-water pressure, lateral soil movement, and negative skin friction on the pile. In this paper, full-scale field testing on two trial embankments built on soft soil is reported and the relative behaviour of these two embankments is compared and discussed. Soft soil underneath both embankments was consolidated before one pile was installed at the centre of each embankment. The pore-water pressure, lateral soil movement, surface settlement, and associated strain at the pile shaft were recorded. The pile capacity was tested immediately and 3 h after pile installation. The monitoring and testing results indicated that preconsolidation with PVDs before piling can effectively reduce the excess pore-water pressure, lateral soil movement, and downdrag on the pile.

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Research paper thumbnail of Simplified Design Procedure for Piled Raft Foundations

In situations where a raft foundation alone does not satisfy the design requirements, it may be p... more In situations where a raft foundation alone does not satisfy the design requirements, it may be possible to enhance the performance of the raft by the addition of piles. The use of a limited number of piles, strategically located, may improve both the ultimate load capacity and the ...

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Research paper thumbnail of General elastic analysis of piles and pile groups

International Journal for Numerical and Analytical Methods in Geomechanics, 2000

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Research paper thumbnail of Probabilistic Applications in Geotechnical Engineering

Probabilistic Applications in Geotechnical Engineering, 2007

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Re-assessment of foundation settlements for the Burj Khalifa, Dubai

Acta Geotechnica, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Foundation Settlement Analysis. De Mello Volume; a Tribute to Professor Dr. Victor F. B. De Mello in Honor of His Contribution to the Development of Geotechnical Engineering in Latin America

Foundation settlements may arise from a number of causes, including: (i) static loads, such as th... more Foundation settlements may arise from a number of causes, including: (i) static loads, such as those imposed by the weight of the structure; (ii) dynamic, repeated or transient loads, such as those produced by machinery or environmental wind and wave loadings; and (iii) changes in moisture content, for example from seasonal fluctuation in the water table, rainfall and evaporation, or the absorption of water by the roots of large trees. The effects of nearby construction (for example excavation, pile driving and de-watering) may also be significant. In this paper attention is concentrated on settlements of saturated soils due to static loads, although many of the principles may be applied to settlements due to other causes, and it must be emphasized that settlements due to the latter two causes listed above may often be as significant as those due to static loads. This paper provides a brief general review of the principles of settlement analysis, and some of the methods available for carrying out settlement calculations. A brief review is also made of procedures for determining the required geotechnical parameters. For the covering abstract of this book see IRRD 836508. (TRRL)

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Pile behaviour — theory and application

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Apr 1, 1990

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Piles subjected to negative friction; a procedure for design

Geotechnical engineering, 1997

This paper emphasizes the fact that when piles are subjected to negative friction, their ultimate... more This paper emphasizes the fact that when piles are subjected to negative friction, their ultimate geotechnical capacity is not significantly influenced, and the main deleterious effects arise from increased settlement and an increased axial force in the pile, which can influence structural integrity. Hand and computer methods for estimating the settlement and maximum load in the pile are described. The hand method assumes full pile-soil slip and agrees well with the computer analysis when the free-field soil movements are relatively large. A simple design approach is developed for estimating the maximum load which can be applied to the head of a pile subjected to negative friction. This load is based on the condition that the pile head settlement should reach an acceptable limiting value, regardless of the settlement of the soil. An example of the application of the computer and hand methods is described, and it is demonstrated that bitumen coating of the piles can allow larger load...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of 2. Development of design charts for concrete pavements and industrial ground slabs

Design applications of raft foundations

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Static and Cyclic Direct Shear Tests on Carbonate Sands

Geotechnical Testing Journal, 1992

This paper examines the static and cyclic behavior of different types of carbonate sediments and ... more This paper examines the static and cyclic behavior of different types of carbonate sediments and one type of silica sand under direct shear test conditions. For both static and cyclic loading, the effects of interface surface roughness, overburden pressure, void ratio, size and shape of grains, and saturation are studied. It is found that the static shear resistance is influenced by most of these factors and that the cyclic behavior depends significantly on the number of cycles and the cyclic displacement amplitude. The amount of crushing caused by cyclic loading is found to depend strongly on particle shape and grading characteristics.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Estimation of Pile Friction Degradation from Shearbox Tests

Geotechnical Testing Journal, 1992

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Behaviour of Pile Groups in Liquefying Soil

This paper presents a simplified method of analysis for pile groups founded in liquefying soil. T... more This paper presents a simplified method of analysis for pile groups founded in liquefying soil. The method involves two main steps. First an effective stress based ground response analysis is carried out to obtain the maximum ground displacements along the pile and the degraded soil modulus over the depth of soil deposit. Next a dynamic analysis is carried out for a single pile in the group assuming that each pile in the group behaves in the same way during the earthquake loading. The method has been verified using centrifuge data, where soil liquefaction has been observed in laterally spreading ground. It is demonstrated that the new method gives good estimate of pile behaviour, despite its relative simplicity

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A review of geological and geotechnical features of some Middle Eastern countries

Innovative Infrastructure Solutions, May 30, 2018

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Design for ground movements

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Warren Centre underground space project

Pages, Jun 7, 1996

Bookmarks Related papers MentionsView impact

Research paper thumbnail of From theory to practice in pile design

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Mar 1, 1989

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A systematic approach to forensic foundation engineering

Proceedings of the Institution of Civil Engineers, May 1, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Design Method for Stabilization of Slopes with Piles. Discussions and Closure

Journal of Geotechnical and Geoenvironmental Engineering, Oct 1, 1999

ABSTRACT A methodology is proposed for the design of slopes reinforced with a single row of piles... more ABSTRACT A methodology is proposed for the design of slopes reinforced with a single row of piles. An existing method which is based on the theory of plasticity is used to find the lateral forces acting on the pile section above the critical surface. A portion of that force is assumed to be mobilized against the movement of the slope. Then, the friction circle method is extended to incorporate the reaction force in the stability analysis. Thus a new stability number that includes the pile reaction is used to determine the modified critical surface and safety factor of the reinforced slope. Finally, a procedure is proposed to achieve an optimum design solution which provides a desirable factor of safety for the slope/pile system.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Closure to “Numerical Modeling of Geotextile-Reinforced Embankments over Deep Cement Mixed Columns Incorporating Strain-Softening Behavior of Columns” by N. N. S. Yapage, D. S. Liyanapathirana, H. G. Poulos, R. B. Kelly, and C. J. Leo

International Journal of Geomechanics, Aug 1, 2015

The writers thank the discussers for their interest and the important points raised by them perta... more The writers thank the discussers for their interest and the important points raised by them pertaining to the original paper. The main aim of the original paper was to demonstrate the application of the extended version of the Mohr-Coulomb model for the simulation of the strain-softening behavior of cement-stabilized soils. The writers validated the model using triaxial data, and then applied it to a case study in which both isolated and attached columns were used, to show the capability of the model in predicting the embankment behavior. Finally, the proposed model was used to demonstrate the progressive failure of a hypothetical embankment with isolated columns in a square pattern

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Tests on Model Instrumented Piles in Calcareous Soil

The annual research report, Apr 1, 1988

This paper describes the results of tests on model piles jacked into beds of reconstituted marine... more This paper describes the results of tests on model piles jacked into beds of reconstituted marine calcareous sediments. The behaviour of a single pile is examined during installation, under static loading and under cyclic loading (both load controlled and displacement controlled). It is found that significant residual stresses exist in the pile after installation. A low skin friction is developed along the pile shaft, primarily due to the reduction of lateral stress which appears to occur during installation of the pile. Cyclic loading generally leads to a further reduction in skin friction, this reduction being a function of the cyclic displacement which the pile undergoes, rather than the cyclic load level. Comparisons are also made with the data obtained from previous tests on small model piles installed into the soil prior to consolidation of the soil bed. These comparisons show the importance of the in situ lateral stress on the skin friction developed under static loading, but suggest that cyclic degradation is not seriously influenced by this factor (a).

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Field study of pile – prefabricated vertical drain (PVD) interaction in soft clay

Canadian Geotechnical Journal, Mar 1, 2020

Piles and prefabricated vertical drains (PVDs) are two well-established inclusions used by geotec... more Piles and prefabricated vertical drains (PVDs) are two well-established inclusions used by geotechnical practitioners when dealing with soft compressible foundations. Induced movements in highly compressible soil can adversely influence the pile response by inducing additional movements and stresses in the piles. Especially, undesirable soil–pile interaction often leads to the development of excess pore-water pressure during pile installation and negative skin friction caused by the settlement of compressible soil surrounding the piles. Additional drainage by PVDs prior to the installation of a pile could reduce excess pore-water pressure, lateral soil movement, and negative skin friction on the pile. In this paper, full-scale field testing on two trial embankments built on soft soil is reported and the relative behaviour of these two embankments is compared and discussed. Soft soil underneath both embankments was consolidated before one pile was installed at the centre of each embankment. The pore-water pressure, lateral soil movement, surface settlement, and associated strain at the pile shaft were recorded. The pile capacity was tested immediately and 3 h after pile installation. The monitoring and testing results indicated that preconsolidation with PVDs before piling can effectively reduce the excess pore-water pressure, lateral soil movement, and downdrag on the pile.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Simplified Design Procedure for Piled Raft Foundations

In situations where a raft foundation alone does not satisfy the design requirements, it may be p... more In situations where a raft foundation alone does not satisfy the design requirements, it may be possible to enhance the performance of the raft by the addition of piles. The use of a limited number of piles, strategically located, may improve both the ultimate load capacity and the ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of General elastic analysis of piles and pile groups

International Journal for Numerical and Analytical Methods in Geomechanics, 2000

Bookmarks Related papers MentionsView impact