Advanced laboratory studies to explore the axial cyclic behaviour of driven piles
File(s)
Author(s)
Aghakouchak, Amin
Type
Thesis
Abstract
Importance of addressing cyclic behaviour when designing piled foundations has been emphasised in recent years. Instrumented full scale field and model pile tests have revealed key features of pile’s axial cyclic response in recent years. Along with those, laboratory tests may be conducted to provide site specific cyclic soil characteristics, but questions arise concerning how to: (i) take into account the pile installation process and (ii) apply the results to assess pile capacity and deformation responses under cyclic loads. This thesis describes an investigation into the cyclic behaviour of Dunkerque and NE34 Fontainebleau sands, performed to support and help analyse field-scale and model pile cyclic loading tests on the same soils. Series of triaxial and HCA cyclic and static tests were performed, following testing schemes developed that reflect the conditions applying adjacent to the pile shafts. Assessments were made of how the cyclic variations of stresses imposed during installation and the period allowed for the sands to creep following such ‘installation’ effects, affect the response to subsequent cycling. Constant-volume cyclic tests involving up to 4500 cycles were imposed from alternative sets of initial conditions that revealed the relationships between the cyclic amplitude, the changes in effective stress and number of cycles as well as the permanent strain accumulation and cyclic stiffness characteristics. Monotonic compression and extension tests were also performed for both sands to help frame their strength, stiffness and critical state properties. Finally, methods are introduced to compare the laboratory results with field and model pile tests.
Version
Open Access
Date Issued
2015-09
Date Awarded
2015-12
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Jardine, Richard
Sim, Way Way
Sponsor
Imperial College London
Atkins (Firm)
JAMM Design and Development Engineering Company
Publisher Department
Civil and Environmental Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)