Piles In Layered Soils Research Articles

Lateral capacity of piles in layered soils using p-y curves : Purkayastha, R D; Sahu, R B Proc Ninth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Bangkok, 9–13 December 1991V1, P279–282. Publ Thailand: Southeast Asian Geotechnical Society, 1991

Lateral capacity of piles in layered soils using p-y curves : Purkayastha, R D; Sahu, R B Proc Ninth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Bangkok, 9–13 December 1991V1, P279–282. Publ Thailand: Southeast Asian Geotechnical Society, 1991

Kinematic seismic response and bending of free-head piles in layered soil

The paper studies the kinematic response of free-head piles. Such pile deformation has triggered structural damage in many strong earthquakes. In this Paper dimensionless parametric graphs for pile bending moments are presented which pertain to characteristic two-layer soil profiles. The results are derived by using an existing rigorous dynamic finite-element code, and by implementing a realistic beam-on-dynamic-Winkler-foundation formulation specifically developed for the kinematic response of piles in layered soil. The Winkler model is shown to reproduce quantitatively even detailed trends observed in the finite-element results; a simple analytical expression is thereby developed for estimating the Winkler stiffness in terms of the local soil Young's modulus and key dimensionless pile/ soil parameters. The study concludes that even relatively flexible piles may not exactly experience the wavy and abruptly changing ground deformation of the free field. The critical region of pile distress due to such kinematic loading is shown to be at or near the interface between alternating soft and stiff soil layers. The magnitude of the bending moment at such critical interface locations depends mainly on the stiffness contrast of the two layers through which the pile penetrates, the excitation frequency and the relative rigidity of the pile. A constraining cap may exert an important effect on such kinematic deformations. L'article étudie la réponse cinématique de pieux à tete-libre. La déformation de ces pieux a en effet occasionné des endommagements structuraux lors de nombreux tremblements de terre de forte amplitude. L'article propose des graphiques à paramètres adimensionnels permettant de calculer le moment fléchissant des pieux et de caractériser des sols bicouches. Les résultats sont calculés à l'aide d'un code dynamique d'éléments finis, préexistant et rigoureux, et d'une formulation réaliste de "Beam-on-Dynamic-Winkler-Foundation" spécialement mise en oeuvre pour la réponse cinématique des pieux dans des sols stratifiés. Le modèle de Winkler permet de reproduire les tendances, même très détaillées, des résultats obtenus par éléments finis. Une expression analytique simple est alors développée. Elle permet d'estimer la raideur de Winkler en terme de module de Young local du sol et de paramètres clés adimensionnel pieu/sol. L'étude montre que meme les pieux relativement flexibles ne supportent pas totalement une déformation rapide et odulante du terrain. La zone critique des pieux sinistrés résultant d'un tel chargement cinématique se trouve au niveau ou à proximité de l'interface sol souple/sol rigide. L'amplitude du moment fléchissant au niveau de ces interfaces critiques dépend principalement du contraste de raideur existant entre les deux couches traversées par le pieu, de la fréquence d'excitation et de la rigidité relative du pieu. Un capuchon de mise sous contrainte pourrait avoir un effet important sur de telles déformations cinéma-tiques.

DISCRETE NUMERICAL ANALYSIS OF GROUP PILES AND THEIR DYNAMIC CHARACTERISTICS

This paper is concerned with the three-dimensional dynamics of group piles in layered soils with emphasis on the pile-soil-pile interaction. The analysis, based on the substructure technique, is made by the finite element method for piles and the Green function method for soils which makes use of the thin layer formulation. Points for investigation is placed on the pile head impedance function and their group effect. The engineering aspect is also addressed to compare the present solution with the current design formula with respect to the pile head spring constant.

Torsional resistance of single pile in layered soil. Technical note: Hache, R A G; Valsangkar, A J J Geotech Engng Div ASCEV114, N2, Feb 1988, P216–220

Torsional resistance of single pile in layered soil. Technical note: Hache, R A G; Valsangkar, A J J Geotech Engng Div ASCEV114, N2, Feb 1988, P216–220

Laterally loaded piles in layered soil : Lee, S L; Kog, Y C; Karunaratne, G P Soils FoundV27, N4, Dec 1987, P1–10

Laterally loaded piles in layered soil : Lee, S L; Kog, Y C; Karunaratne, G P Soils FoundV27, N4, Dec 1987, P1–10

Torsional Resistance of Single Pile in Layered Soil

Analysis and mathematical solutions are presented for a torsionally loaded pile embedded in two-layered soil deposit assuming elastic behavior. Soil shear modulus is assumed to be constant in each layer or to vary linearly with depth. Numerical results are obtained for practical range of parameters and nondimensional charts are presented for design purposes

Behaviour of rigid piles in layered soils under eccentric and inclined loads

Behaviour of rigid piles in layered soils under eccentric and inclined loads

Axially loaded piles in layered soils

Axially loaded piles in layered soils

Axially Loaded Piles in Layered Soil

The behavior of axially loaded piles in layered soil is investigated in terms of effective stresses, using a rigorous elastic load transfer theory. Following the technique of Muki and Sternberg, the problem is decomposed into extended soil layers with elastic properties of the layered soil and a fictitious pile characterized by Young's moduli equal to the difference between the Young's modulus of the real pile and the respective Young's moduli of the soil layers. The unknown fictitious pile force and the fictitious pile top settlement are determined by equating the vertical displacement of the fictitious pile to the vertical displacement caused by a system of interactive forces in the extended soil layers along the centroidal axes of the original pile location. The real pile force and displacement can then be calculated once the fictitious pile force is known. Extensive parametric studies with regard to the base load, bearing layer load, and pile top settlement are presented graphically for the design and analysis of axially loaded piles in layered soil.

Behaviour of rigid piles in layered soils under eccentric and inclined loads

The lateral soil pressures, ultimate bearing capacity, and displacements of instrumented vertical single rigid model piles in a layered system consisting of soft clay overlying loose sand and subjected to vertical eccentric and central inclined loads have been investigated. The variation of lateral soil pressures and the tip resistance of the pile are analysed with respect to the total load or moment on the pile. Theoretical estimates of pile capacity in homogeneous soils under pure moment and under horizontal load have been extended to piles in a layered system. For intermediate eccentricities and inclinations of the load, the pile capacity can be estimated from simple interaction relations or semiempirical eccentricity and inclination factors. The pile displacements are analysed in the light of linear elastic theory and nondimensional p − y curves. Reasonable agreement has been found between the measured and predicted values. Key words: bearing capacity, clay, displacements, eccentric load, horizontal load, lateral pressure, layered system, model test, pile, sand.

Non-negative skin friction piles in layered soil : Lee, S L; Sithichaikasem, S Proc International Conference on Case Histories in Geotechnical Engineering, Rolla, Missouri, 6–11 May 1984V1, P285–288. Publ St Louis: Geotechnical Engineering, 1984

Non-negative skin friction piles in layered soil : Lee, S L; Sithichaikasem, S Proc International Conference on Case Histories in Geotechnical Engineering, Rolla, Missouri, 6–11 May 1984V1, P285–288. Publ St Louis: Geotechnical Engineering, 1984

Horizontal response of piles in layered soils : Gazetas, G; Dobry, R J Geotech Engng Div ASCEV110, NGT1, Jan 1984, P20–40

Horizontal response of piles in layered soils : Gazetas, G; Dobry, R J Geotech Engng Div ASCEV110, NGT1, Jan 1984, P20–40

Horizontal Response of Piles in Layered Soils

An inexpensive and realistic procedure is developed for estimating the lateral dynamic stiffness and damping of flexible piles embedded in arbitrarily layered soil deposits. Starting point is the determination of the pile deflection profile for a static force at the top using any reasonable method—beam‐on‐Winkler foundation, finite elements, well‐instrumented pile load tests in the field, etc. Material as well as radiation damping due to waves emanating at different depths from the pile‐soil interface are rationally taken into account; the overall equivalent damping at the top of the pile is then obtained as a function of frequency by means of a suitable energy relationship. The method is applied to study the dynamic behavior of three different piles embedded in two idealized and one actual layered soil deposit; the results of the method, obtained by hand computations, compare favorably with the results of three dimensional dynamic finite element analyses.

Laterally loaded piles in layered soils : Reese, L C; Allen, J D; Hargrove, J Q Proc 10th International Conference on Soil Mechanics and Foundation Engineering, Stockholm, 15–19 June 1981, V2, P819–822. Publ Rotterdam: A. A. Balkema, 1981

Laterally loaded piles in layered soils : Reese, L C; Allen, J D; Hargrove, J Q Proc 10th International Conference on Soil Mechanics and Foundation Engineering, Stockholm, 15–19 June 1981, V2, P819–822. Publ Rotterdam: A. A. Balkema, 1981

Lateral resistance and deflection of rigid walls and piles in layered soils : Meyerhof, G G; Mathur, S K; Valsangkar, A J Can Geotech J, V18, N2, May 1981, P159–170

Lateral resistance and deflection of rigid walls and piles in layered soils : Meyerhof, G G; Mathur, S K; Valsangkar, A J Can Geotech J, V18, N2, May 1981, P159–170

Lateral resistance and deflection of rigid walls and piles in layered soils

The ultimate lateral resistance and the lateral deflection at working loads of rigid vertical walls and piles with a free head subjected to horizontal load and embedded in two-layered soils of sand and clay have been investigated. Part 1 deals with the behaviour of rigid walls, and the analyses are compared with the results of model wall tests in layered soils. Part 2 treats the behaviour of rigid piles, and the analyses are compared with the results of model tests on piles and pile groups in layered soils and some field case records.

Bearing capacity of piles in layered soils. Part 1, clay overlying sand. Part 2, sand overlying clay : Meyerhof, G G; Sastry, V V R N Can Geotech J, V15, N2, May 1978, Part 1, P171–182, Part 2, P183–189

Bearing capacity of piles in layered soils. Part 1, clay overlying sand. Part 2, sand overlying clay : Meyerhof, G G; Sastry, V V R N Can Geotech J, V15, N2, May 1978, Part 1, P171–182, Part 2, P183–189

Horizontally loaded piles in layered soils : Dordi, C M Proc Specialty Session 10, 9th International Conference on Soil Mechanics and Foundation Engineering, Tokyo, July 1977, P65–70. Publ Tokyo: Japanese Assoc for Steel Pipe Piles, 1977

Horizontally loaded piles in layered soils : Dordi, C M Proc Specialty Session 10, 9th International Conference on Soil Mechanics and Foundation Engineering, Tokyo, July 1977, P65–70. Publ Tokyo: Japanese Assoc for Steel Pipe Piles, 1977

Bearing capacity of piles in layered soils. Part 1. Clay overlying sand

The paper summarizes investigations on jacked and driven piles in non-uniform soils consisting of clay and sand. Part 1 deals with the bearing capacity of piles penetrating through clay into sand whereas Part 2 discusses the case of piles in a sand stratum overlying clay. Preliminary tests on small model piles have been undertaken to study the effects on the point resistance of parameters such as the strength and thickness of a clay stratum, the strength ratio of soils in the two layers and the geometry of the layers. Based on these results, tests on a 76 mm diameter instrumented steel pile and a 36 mm diameter static cone penetrometer have been carried out for selected combinations of the variables involved.The test results are analysed to determine the influence of clay thickness and strength on the point resistance of piles in sand, expressed by a non-dimensional clay strength factor λ, and parameters influencing λ are discussed. The effect of layering on the shaft friction in sand and the radial stresses along the pile length are studied. The efficiency of small groups of model piles in layered soils is obtained. Field data are analysed, including scale effects, and simple design rules are suggested to estimate the bearing capacity of piles in layered soils.

Bearing capacity of piles in layered soils. Part 2. Sand overlying clay

The previous Part 1 of this paper deals with the bearing capacity of piles penetrating through clay into sand. In the present Part 2 the case of piles penetrating into a sand stratum overlying clay is discussed. As the pile points approach the sand–clay interface, the piles may fail by punching through the sand into the underlying clay. Test results on instrumented model piles and field data are analysed to estimate the punching resistance of piles in layered soils.