Dynamic response of pile groups subjected to horizontal loads

2020 ◽  
Vol 57 (4) ◽  
pp. 469-481 ◽  
Author(s):  
Lubao Luan ◽  
Xuanming Ding ◽  
Changjie Zheng ◽  
George Kouretzis ◽  
Qi Wu
Keyword(s):  
Numerical Methods ◽  
Soil Reaction ◽  
Pile Groups ◽  
Dynamic Impedance ◽  
Interaction Factor ◽  
Cylindrical Piles ◽  
Pile Interaction ◽  
Efficient Alternative ◽  
Displacement Based ◽  
Surrounding Soil

This paper presents an analytical method for calculating the dynamic impedance of pile groups comprising an arbitrary number of cylindrical piles connected with a rigid cap. The solution allows consideration of ground waves due to pile vibration that propagate along both the horizontal and vertical planes, as well as the effect of the actual pile section geometry on the reaction from the surrounding soil. For that, we introduce a dynamic pile–soil–pile interaction factor that is defined on the basis of soil reaction developing on receiver piles, instead of the classical displacement-based interaction factor used in past studies. Despite the fact that the solution is applicable to problems where low-to-moderate soil strains are expected to develop, it poses as an attractive, efficient alternative to numerical methods for the analysis of very large pile groups.

Influence of Pile Geometry on Responses of End-Bearing Pile Groups Subjected to Vertical Dynamic Loads

2020 ◽  
Vol 20 (04) ◽  
pp. 2050050
Author(s):  
Lubao Luan ◽  
Xin Deng ◽  
Weiting Deng ◽  
Chenglong Wang ◽  
Xuanming Ding
Keyword(s):  
Superposition Principle ◽  
Pile Group ◽  
Dynamic Responses ◽  
Stress Distributions ◽  
Pile Groups ◽  
Pile Head ◽  
Interaction Factor ◽  
Pile Interaction ◽  
Refined Technique ◽  
End Bearing Pile

An analytical solution is presented for evaluating the dynamic responses of pile groups subjected to vertical harmonic loads. The solution allows us to consider the effects of pile geometry on the pile head impedance of the vertically loaded pile groups by the use of a new dynamic interaction factor. To this end, the stress distributions of the soil surrounding the vertically vibrating pile is first determined for calculating the pile–pile interaction factor, instead of the classical interaction factor based on two-pile displacements in past studies. Accordingly, the impedances of the pile group are derived using the proposed pile–pile interaction factor and the superposition principle. Some selected examples are presented to demonstrate the proposed refined technique for evaluating the dynamic characteristics of the pile group.

Analysis for Axial Vibration and Internal Forces of Totally and Partially Embedded Pile Groups with Flexible Caps

2010 ◽  
Vol 163-167 ◽  
pp. 3860-3867
Author(s):  
Qing Ren ◽  
Mao Song Huang
Keyword(s):  
Wind Farm ◽  
Mass Density ◽  
Offshore Wind ◽  
Parameter Study ◽  
Pile Groups ◽  
Inertial Interaction ◽  
Soil Deposits ◽  
Pile Interaction ◽  
Internal Forces ◽  
Dynamics Response

In this paper, a simplified analytical method is developed for the axial harmonic response of totally and partially embedded pile groups in homogeneous and layered soil deposits. Based on BDWF model, finite element sub-structure method is used to setup the dynamic model of cap-pile groups which can precisely simulate kinetic interaction and inertial interaction. A comprehensive parameter study focuses on the influence of caps’ elastic modulus and mass density on pile groups’ dynamic response, and then points out the limition of rigid cap in practical design. An approximate solution is finally presented for the internal forces distributed on pile heads due to pile-to-pile interaction. The solution of above approach was compared with that of traditional simplified model (rigid and massless cap solution) in simulating an in-site experiment and dynamics response of partially embedded pile groups for offshore wind farm.

Design procedure for landslide stabilization using sheet pile ribs

2019 ◽  
Vol 56 (4) ◽  
pp. 514-525 ◽  
Author(s):  
James R. Bartz ◽  
C. Derek Martin ◽  
Michael T. Hendry
Keyword(s):  
Limit Equilibrium ◽  
Unit Length ◽  
Design Procedure ◽  
Soil Reaction ◽  
Case Study Site ◽  
Rail Line ◽  
Pile Interaction ◽  
Stabilization Technique ◽  
Laterally Loaded

A design procedure was developed for a relatively unknown slope stabilization technique consisting of a series of parallel sheet piles installed parallel to the direction of slope movement. This technique was introduced in Alberta by R.M. Hardy in the 1970s and is locally referred to as “Hardy Ribs.” A case study is discussed where Canadian National (CN) Rail installed Hardy Ribs to stabilize a landslide affecting its rail line in western Manitoba. A proposed design procedure is discussed that consists of a de-coupled approach with a separate limit equilibrium slope stability analysis and laterally loaded pile analysis using p–y curves, where p is the soil reaction per unit length and y is the lateral deflection of the pile, to model the soil–pile interaction. Example calculations are provided for the proposed design procedure for the CN case study site to illustrate its use and to estimate the stabilizing effect from the Hardy Ribs at this site.

scholarly journals Numerical modelling of perimeter pile groups in clay

2013 ◽  
Vol 50 (3) ◽  
pp. 250-258 ◽  
Author(s):  
A.V. Rose ◽  
R.N. Taylor ◽  
M.H. El Naggar
Keyword(s):  
Load Distribution ◽  
Load Capacity ◽  
Relative Effectiveness ◽  
Pile Group ◽  
Block Type ◽  
Pile Groups ◽  
Total Load ◽  
Group Behaviour ◽  
Pile Interaction ◽  
Spacing Length

The load distribution among piles in a group varies such that the inner piles often carry a smaller share of the total load compared to the outer piles, which is a result of increased soil–pile interaction. The main objective of this paper is to establish the relative effectiveness of pile groups with no inner piles (perimeter group), when compared to the more common grid configuration. The numerical investigation utilized the finite element programme ABAQUS and considered a range of variables that affect pile group behaviour including number of piles, pile spacing, length/diameter ratio, and soil strength. It was demonstrated that a complete grid group is less efficient than a perimeter group, where efficiency is defined as the load capacity of the whole group expressed as a ratio of the number of piles in the group multiplied by the load capacity of a single isolated pile. Efficiencies close to unity were observed for some perimeter groups. Perimeter groups also showed that a “block” type group failure could occur, where piles were placed at a spacing of less than 2.0 pile diameters,d, centre-to-centre. This often, but not always, led to a reduction in the efficiency of the pile group.

scholarly journals An Experimental Study on Pile Spacing Effects under Lateral Loading in Sand

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Mahdy Khari ◽  
Khairul Anuar Kassim ◽  
Azlan Adnan
Keyword(s):  
Pile Group ◽  
Experimental Investigations ◽  
Pile Groups ◽  
Dense Sand ◽  
Spacing Effects ◽  
Pile Diameter ◽  
Lateral Resistance ◽  
Model Pile ◽  
Pile Interaction ◽  
Subgrade Modulus

Grouped and single pile behavior differs owing to the impacts of the pile-to-pile interaction. Ultimate lateral resistance and lateral subgrade modulus within a pile group are known as the key parameters in the soil-pile interaction phenomenon. In this study, a series of experimental investigation was carried out on single and group pile subjected to monotonic lateral loadings. Experimental investigations were conducted on twelve model pile groups of configurations 1 × 2, 1 × 3, 2 × 2, 3 × 3, and 3 × 2 for embedded length-to-diameter ratiol/d= 32 into loose and dense sand, spacing from 3 to 6 pile diameter, in parallel and series arrangement. The tests were performed in dry sand from Johor Bahru, Malaysia. To reconstruct the sand samples, the new designed apparatus, Mobile Pluviator, was adopted. The ultimate lateral load is increased 53% in increasing ofs/dfrom 3 to 6 owing to effects of sand relative density. An increasing of the number of piles in-group decreases the group efficiency owing to the increasing of overlapped stress zones and active wedges. A ratio ofs/dmore than6dis large enough to eliminate the pile-to-pile interaction and the group effects. It may be more in the loose sand.

scholarly journals Experimental and Numerical Study of Pile-to-Pile Interaction Factor in Sandy Soil

2016 ◽  
Vol 161 ◽  
pp. 1030-1036 ◽  
Author(s):  
Mehdi Modarresi ◽  
Habib Rasouli ◽  
Abbasali Taghavi Ghalesari ◽  
Mohammad Hassan Baziar
Keyword(s):  
Sandy Soil ◽  
Numerical Study ◽  
Interaction Factor ◽  
Pile Interaction

Experimental study of interaction and coupling effects in pile groups subjected to torsion

2008 ◽  
Vol 45 (7) ◽  
pp. 1006-1017 ◽  
Author(s):  
L. G. Kong ◽  
L. M. Zhang
Keyword(s):  
Coupling Effect ◽  
Pile Group ◽  
Test Results ◽  
Pile Groups ◽  
Coupling Effects ◽  
Lateral Resistance ◽  
Torsional Resistance ◽  
Pile Interaction ◽  
Group Configuration ◽  
Centrifuge Model Tests

Piles in a pile group subjected to torsion simultaneously mobilize lateral and torsional resistances. Hence, complicated pile–soil–pile interaction effects and load deformation coupling effects occur in the pile group. In this study, a series of centrifuge model tests were carried out to investigate these effects in three-diameter spaced 1 × 2, 2 × 2, and 3 × 3 pile groups subjected to torsion in both loose and dense sands. The test results showed that the effect of horizontal movement of a pile on lateral behaviors of its adjacent piles is significant in 3 × 3 pile groups and such effect varies with group configuration and pile position. The p-multiplier concept can be used to quantify the effect and values for the p-multiplier are suggested. The effect of lateral movement of a pile on the torsional resistances of its adjacent piles and the effect of torsional movement of a pile on the lateral resistances of its adjacent piles were found to be minor in these tests. For an individual pile in a pile group subjected to torsion, the mobilized lateral resistance was found to substantially increase the torsional resistance of the pile. Such a coupling effect is quantified by a coupling coefficient, β, which describes the contribution of subgrade reaction to the increase of torsional shear resistance.

Settlement analysis of pile groups in layered soils

2006 ◽  
Vol 43 (8) ◽  
pp. 788-801 ◽  
Author(s):  
Roberto Cairo ◽  
Enrico Conte
Keyword(s):  
Dynamic Stiffness ◽  
Pile Group ◽  
Nonlinear Behaviour ◽  
Layered Soils ◽  
Pile Groups ◽  
Linear Elastic ◽  
Vertical Loading ◽  
Stiffness Matrices ◽  
Interaction Factor ◽  
Settlement Analysis

This paper presents a method to perform a nonlinear analysis of pile groups subject to vertical loading. The method makes use of the dynamic stiffness matrices to simulate the response of layered soils. These matrices are incorporated in a calculation procedure that is computationally very efficient because the response of a pile group can be achieved using essentially the solution for a single pile. The method is first used to perform a linear elastic analysis of pile groups and is then extended to include the nonlinearity effects. In this context, the widely accepted approach is adopted in which nonlinearity is considered to be confined in a narrow zone close to each pile, whereas outside this zone the soil is assumed to behave as a linear elastic medium. Moreover, a global interaction factor is introduced to account for the interaction among the piles in the group. The theoretical predictions from the proposed method are compared with experimental measurements from several published full-scale and model tests on pile groups loaded up to failure. The agreement between predicted and observed behaviour is found to be very satisfactory, even approaching the ultimate load, when the results of loading tests on single piles are available and the group efficiency with respect to the failure load is close to unity.Key words: pile groups, settlement analysis, nonlinear behaviour, layered soils.

Sign in / Sign up

Export Citation Format

Share Document