Imperial College London

ProfessorRichardJardine

Faculty of EngineeringDepartment of Civil and Environmental Engineering

Consul for the Faculty of Engineering & the Business School
 
 
 
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Contact

 

+44 (0)20 7594 6083r.jardine CV

 
 
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Assistant

 

Ms Sue Feller +44 (0)20 7594 6077

 
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Location

 

532Skempton BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

337 results found

Guo L, Cai Y, Jardine RJ, Yang Z, Wang Jet al., 2017, Undrained behaviour of intact soft clay under cyclic paths that match vehicle loading conditions, Canadian Geotechnical Journal, Vol: 55, Pages: 90-106, ISSN: 1208-6010

Vehicle traffic loading appears to contribute significantly to long term settlement beneath highways, airport runways and metro lines in China. Wheel loading imposes cycles in both the magnitude and direction of the principal stresses acting on the soils beneath pavement or rail-track structures. Conventional cyclic triaxial testing, which is not capable of imposing such stress paths may underestimate how heavy traffic loading affects any underlying soft clay layers. Hollow cylinder apparatus (HCA) can simulate such traffic loading stress paths more accurately, including rotation of the principal stress directions. This paper presents a systematic experimental study of cyclic HCA (CHCA) tests on K0-consolidated saturated soft clay involving cyclic variations in both vertical and torsional shear stresses, along with a parallel programme of cyclic triaxial (CT) tests, considering the undrained response of saturated samples of intact soft clay. It is shown that when applied above certain critical cyclic stress ratios, principal stress rotation accelerates excess pore water pressure and permanent strain development. Corresponding changes are also seen in the resilient modulus and damping ratio trends. The discrepancies between the behaviour of CHCA and equivalent cyclic triaxial tests grow as the cyclic stress ratios increase.

Journal article

Liu T, Aghakouchak A, Taborda DMG, Jardine RJet al., 2017, Advanced laboratory characterization of a fine marine sand from Dunkirk, France, 19th International Conference on Soil Mechanics and Geotechnical Engineering, Publisher: ICSMGE, Pages: 439-442

Dense fine marine sand is encountered at the Dunkirk ZIP Les Huttes test site located in northern France that has beenemployed extensively for research into pile behaviour. Laboratory testing of the sand is required to fully characterise site conditionsand determine parameter inputs for analysing the field pile experiments. This paper summarises some of the comprehensivelaboratory testing programmes undertaken to investigate the sand’s mechanical behaviour, including stress-strain relationships,stiffness and strength anisotropy, cyclic behaviour, and interface shear properties. The paper first reviews the site’s geotechnicalconditions and their potential variations over time. The stringent laboratory requirements that are necessary for the accuratemeasurement of shear stiffness, strength, and creep strains are then discussed, before presenting illustrative results regarding thesand’s small strain stiffness and time-dependent behaviour. The importance of reproducing site conditions and stress states are alsoaddressed in relation to integrating the laboratory research with field observations and analyses of both recent and historical pilingexperiments at the Dunkirk test site.

Conference paper

Brosse A, Hosseini Kamal R, Jardine RJ, Coop MRet al., 2017, The shear stiffness characteristics of four Eocene-to-Jurassic UK stiff clays, Géotechnique, Vol: 67, Pages: 242-259, ISSN: 0016-8505

Journal article

Brosse AM, Jardine RJ, Nishimura S, 2017, The undrained shear strength anisotropy of four Jurassic to Eocene stiff clays, Géotechnique, Vol: 67, Pages: 653-671, ISSN: 0016-8505

The shear strength of heavily overconsolidated, stiff-to-hard plastic clays is crucial to their stability and also influential on the ground movements they develop in many geotechnical engineering applications. This paper considers the shear strength anisotropy of the London, Gault, Kimmeridge and Oxford clays through advanced hollow cylinder experiments on multiple high-quality samples taken at similar depths from inland sites where the geotechnical profiles have been established by comprehensive laboratory and in situ testing. Suites of undrained tests are reported, which loaded specimens from their in situ stress states to reach ultimate failure at pre-defined final major principal stress axis orientations defined in the vertical plane, while also controlling or monitoring the intermediate principal stress ratio, b. Both stress path and simple shear tests were undertaken with the hollow cylinder apparatus, which offers key advantages over conventional simple shear equipment. The interpretation reveals patterns of marked shear strength anisotropy that impact significantly on numerous geotechnical engineering applications.

Journal article

Cai YQ, Guo L, Jardine RJ, Yang ZX, Wang Jet al., 2016, Stress–strain response of soft clay to traffic loading, Géotechnique, Vol: 67, Pages: 446-451, ISSN: 0016-8505

Approximately 25% of China's 120 000 km of expressway, as well as many new metro lines and airports, rest on soft clay deposits. However, service settlements are proving larger than expected, especially in southeast China. This note describes laboratory experiments on K0-consolidated intact samples of soft clay taken near Wenzhou, south-east China, that explore whether cyclic traffic wheel loading contributes significantly to the observed settlement trends. Cyclic triaxial (CT) tests are reported together with cyclic hollow cylinder (CHCA) experiments that imposed cardioid-shaped 2τzθ − (Δσz − Δσθ) stress paths. Cyclic principal stress axis rotation is shown to have an important influence on vertical straining. Once a certain threshold has been exceeded, the resilient and permanent strains developed in the CHCA tests become progressively larger than their counterparts in CT tests conducted at the same vertical cyclic stress ratio, with trends that diverge progressively as vertical cyclic stress ratio increases. Critical cyclic stress ratios can be defined that divide the response into (a) stable, (b) metastable and (c) unstable cyclic ranges. The novel experimental approach and high-quality data reported should aid practitioners and modellers in developing new analyses to address this economically significant geotechnical problem.

Journal article

Brosse AM, Jardine RJ, Nishimura S, 2016, Undrained stiffness anisotropy from Hollow Cylinder experiments on four Eocene-to-Jurassic UK stiff clays, Canadian Geotechnical Journal, Vol: 54, Pages: 313-332, ISSN: 1208-6010

The paper describes the anisotropic undrained stiffness behaviour of four medium-plasticity heavily overconsolidated UK stiff marine clays as revealed through Hollow Cylinder testing. The experiments contributed to two broader studies on stiff-to-hard London, Gault, Kimmeridge, and Oxford clay strata. They involved static and dynamic testing of multiple high quality natural specimens sampled at similar depths from inland sites. This paper explores the directional dependency of the clays’ highly non-linear undrained stiffness characteristics. New data-analysis approaches are outlined that allow the stiffnesses associated with one dimensional vertical, horizontal or pure horizontal shear modes to be isolated in complex undrained stress paths. In the presented experiments, loading progressed from in-situ stresses to reach ultimate failure at a range of final major principal stress orientation angles α (defined in the vertical plane) while keeping fixed values of the intermediate principal stress ratio, b. The tests reveal strong undrained stiffness anisotropy that can impact significantly on the prediction and understanding of ground deformation patterns in numerous geotechnical engineering applications.

Journal article

Jardine RJ, Yang ZX, Guo WB, 2016, Design method reliability assessment from an extended database of axial load tests on piles driven in sand, Canadian Geotechnical Journal, Vol: 54, Pages: 59-74, ISSN: 1208-6010

The accurate prediction of axial capacity remains a challenging task for piles driven in sands. Rigorous database studies have become key tools for assessing the efficacy of design methods. This paper employs the 117 high-quality entries in the recently developed Zhejiang University – Imperial College London (ZJU–ICL) database to check for potential biases between nine prediction procedures, considering a range of factors. The analysis highlights the critical importance of addressing age after driving, open and closed ends, tension versus compression, and concrete compared to steel. It also shows the hierarchy of reliability parameters associated with the alternative approaches. The “full” Imperial College pile (ICP) approach and The University of Western Australia (UWA) approaches are found to have significant advantages in eliminating potential biases. It is also argued that design load and resistance or safety factors should be varied to match the design and site investigation methods applied, as well as the loading uncertainty and degree of load cycling, which often vary between applications. Noting that predictions for base capacities Qb are inherently less reliable than for shaft Qs, especially in rapidly varying ground profiles, credible lower bound parameters (cone resistance, qc) are recommended for Qb assessment. It is also recommended that the potential effects of cycling be addressed carefully in cases that involve substantial environmental loading.

Journal article

Jardine RJ, Brosse A, Coop MR, Hosseini-Kamal Ret al., 2015, Shear strength and stiffness anisotropy of geologically aged stiff clays., International Symposium on Deformation Behaviour of Geomaterials, Publisher: IOS Press, Pages: 156-191

This paper considers the deformation behaviour of four geologically aged, medium-plasticity, heavily overconsolidated stiff clays that affect a broad swathe of infrastructure projects in the SE of the United Kingdom. Static triaxial and hollow cylinder stress path experiments on high quality samples are examined along with dynamic multi-axial bender element and resonant-column measurements. Patterns of undrained shear strength anisotropy are revealed that are governed by the clays' meso and micro-structures. The clays are brittle in shear and their stiffness characteristics are shown to be markedly anisotropic, highly non-linear and pressure dependent. The results obtained have many implications for practical geotechnical engineering.

Conference paper

Byrne BW, McAdam RA, Burd HJ, Houlsby GT, Martin CM, Gavin K, Doherty P, Igoe D, Zdravkovic L, Taborda DMG, Potts DM, Jardine RJ, Sideri M, Schroeder FC, Muir Wood A, Kallehave D, Skov Gretlund Jet al., 2015, Field testing of large diameter piles under lateralloading for offshore wind applications, 16th European Conference on Soil Mechanics and Geotechnical Engineering, Publisher: ICE Publishing

Offshore wind power in the UK, and around Europe, has the potential to deliver significant quantities of renewable energy. The foundation is a critical element in the design. The most common foundation design is a single large diameter pile, termed a monopile. Pile diameters of between 5m and 6m are routinely used, with diameters up to 10m or more, being considered for future designs. Questions have been raised as to whether current design methods for lateral loading are relevant to these very large diameter piles. To explore this problem a joint industry project, PISA, co-ordinated by DONG Energy and the Carbon Trust, has been established. The aim of the project is to develop a new design framework for laterally loaded piles based on new theoretical developments, numerical modelling and bench-marked against a suite of large scale field pile tests. The project began in August 2013 and is scheduled to complete during 2015. This paper briefly outlines the project, focusing on the design of the field testing. The testing involves three sizes of pile, from 0.27m in diameter through to 2.0m in diameter. Two sites will be used; a stiff clay site and a dense sand site. Tests will include monotonic loading and cyclic loading. A suite of site investigation will be carried out to aid interpretation of the field tests, and will involve in-situ testing, standard laboratory testing and more advanced laboratory testing.

Conference paper

Aghakouchakn A, Sim WW, Jardine RJ, 2015, Stress-path laboratory tests to characterise the cyclic behaviour of piles driven in sands, SOILS AND FOUNDATIONS, Vol: 55, Pages: 917-928, ISSN: 0038-0806

Recent publications have emphasised the importance of addressing cyclic behaviour when designing piled foundations. Laboratory tests may be conducted to provide site-specific cyclic soil characteristics, but questions arise concerning: (i) how to take into account the pile installation process and (ii) how to apply the results to assess pile capacity and deformation responses under cyclic loads. This paper describes an investigation into the cyclic behaviour of Dunkerque and NE34 Fontainebleau sands, performed to support and to help analyse field-scale and model pile cyclic loading tests on the same soils. Forty computer-controlled, locally instrumented, cyclic and static triaxial tests were performed, following testing schemes that were developed to reflect the conditions adjacent to the pile shafts. Assessments were made of how the cyclic variations in stress imposed during installation and the period allowing for the two types of sand 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 among the cyclic deviatoric amplitude, the changes in mean effective stress and the number of cycles as well as the permanent strain accumulation and the cyclic stiffness characteristics. Monotonic compression and extension tests are also presented for both sands to help frame their strength, stiffness and critical state properties. A synthesis with previously obtained cyclic pile test trends confirms the practical applicability of the results obtained.

Journal article

Gavin K, Jardine RJ, Karlsrud K, Lehane BMet al., 2015, The Effects of Pile Ageing on the Shaft Capacity of Offshore Piles in Sand., International Symposium Frontiers in Offshore Geotechnics, Publisher: CRC Press, Pages: 129-151

A number of field studies suggest that the axial capacity of driven piles in sand increases withtime. Field test programmes were performed by a number of research groups to examine this aspect of pilebehaviour. The paper presents a summary of the findings from these experiments. It also reviews laboratorypile and element testing performed to provide further insights into the mechanisms controlling pile ageing.

Conference paper

Yang ZX, Jardine RJ, Zhu BT, Rimoy Set al., 2015, Closure to "Stresses Developed around Displacement Piles Penetration in Sand" by Z. X. Yang, R. J. Jardine, B. T. Zhu, and S. Rimoy, JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING, Vol: 141, ISSN: 1090-0241

Journal article

Yang ZX, Guo WB, Zha FS, Jardine RJ, Xu CJ, Cai YQet al., 2015, Field Behavior of Driven Prestressed High-Strength Concrete Piles in Sandy Soils, Journal of Geotechnical and Geoenvironmental Engineering, Vol: 141, ISSN: 1943-5606

Driven piles are used widely both offshore and onshore. However, accurate axial capacity and load-displacement prediction is difficult at sand-dominated sites, and offshore practice is moving towards cone penetration test (CPT) based design methods developed from instrumented pile research and database studies. However, onshore use of these methods remains limited; there is a paucity of high quality case histories to assess their potential benefits clearly, and application in layered profiles may be uncertain. This paper presents new tests on prestressed concrete (PHC) pipe piles driven in sands for a major new Yangtze River bridge project in China, assessing the performance of the ‘new CPT’ and conventional capacity approaches, considering the influence of weak sublayers on base resistance and noting the marked changes in shaft capacity that apply over time.

Journal article

Doherty P, Igoe D, Murphy G, Gavin K, Preston J, McAvoy C, Byrne BW, Mcadam R, Burd HJ, Houlsby GT, Martin CM, Zdravkovic L, Taborda DMG, Potts DM, Jardine RJ, Sideri M, Schroeder FC, Wood AM, Kallehave D, Gretlund JSet al., 2015, Field validation of fibre Bragg grating sensors for measuring strain on driven steel piles, GEOTECHNIQUE LETTERS, Vol: 5, Pages: 74-79, ISSN: 2049-825X

Journal article

Yang ZX, Jardine RJ, Guo WB, Chow Fet al., 2015, A new and openly accessible database of tests on piles driven in sands, Géotechnique Letters, Vol: 5, Pages: 12-20, ISSN: 2045-2543

Journal article

Yang Z, Jardine R, Guo W, Chow Fet al., 2015, A Comprehensive Database of Tests on Axially Loaded Piles Driven in Sand, ISBN: 9780128046555

© 2016 Zhejiang University Press Co., Ltd. Published by Elsevier Inc. All rights reserved. A Comprehensive Database of Tests on Axially Loaded Driven Piles in Sands reviews the critical need to develop better load-test databases for piles driven in sands. The key quality parameters, population of current entries and reporting formats are described before offering preliminary results obtained from comparisons between axial capacities calculated by various predictive approaches and site measurements. This book also shows that the "simplified" and "offshore" ICP and UWA variants proposed by some practitioners are over-conservative and that their use could be discontinued. The new pile capacity and stiffness database offers a broad scope for evaluating potential prediction biases relating to a wide range of soil and pile parameters. Submission of further high quality tests for inclusion in regularly updated versions is encouraged. Presents a comprehensive and updated database for piles driven in predominantly silica sands. Features reviews of the design procedures for driven piles in sand. Assesses the performance of various mainstreams design procedures applied for piles driven in sand. Provides comprehensive information of case histories of pile load tests.

Book

Rimoy S, Silva M, Jardine R, Yang ZX, Zhu BT, Tsuha CHCet al., 2015, Field and model investigations into the influence of age on axial capacity of displacement piles in silica sands, Geotechnique, Vol: 65, Pages: 576-589, ISSN: 0016-8505

© 2015 Thomas Telford Services Ltd, All right resereved. The axial capacities of piles driven in silica sands are known to grow over the months that follow installation, long after all driving-induced pore pressures have dissipated. However, there is uncertainty over the processes that govern the observed set-up and how they may vary from case to case. This paper evaluates three hypotheses against evidence from updated field test databases and laboratory investigations with highly instrumented and pressurised model piles. Potential influential factors are considered including: pile and sand particle sizes, installation style, access to free water, test conditions and external stress change cycles. Laboratory local stress measurements support the hypothesis that moderation, over time, of the extreme stress distributions developed during installation is a key contributor to capacity growth, while field tests confirm the action of enhanced dilation near the shaft. However, field and laboratory piles show paradoxically different ageing trends. The paper proposes that the fractured but compacted sand shear zone that forms around pile shafts during installation leads to set-up being far more significant with large field driven piles than in model tests.

Journal article

Jardine RJ, Merritt AS, Schroeder FC, 2015, The ICP design method and application to a North Sea offshore wind farm, Pages: 247-256, ISSN: 0895-0563

© ASCE 2015. This paper outlines the Imperial College Pile (ICP) approach for developing reliable predictions for the axial capacity of driven piles. The ICP's advantages over traditional design methods have led to widespread use in offshore oil and gas developments. The methods are now playing a critical role in major Northern European offshore wind projects. Hundreds of large steel tubular piles are being driven in the North and Baltic seas and improving design efficiency is crucial to the industry's economic success. This paper provides an overview of the development of the ICP design methods and summarizes their key features, together with experience-based guidance on their application. Their application is illustrated by reference to the North Sea Borkum West II wind farm, where 40 turbines have been installed on steel tripods founded on large diameter steel piles driven in very dense sands. The paper reports how the significant effects of axial and lateral cyclic loading were addressed for Borkum West II through the ICP design methodology.

Conference paper

Zwanenburg C, Jardine RJ, 2015, Laboratory, in situ and full-scale load tests to assess flood embankment stability on peat, Geotechnique, Vol: 65, Pages: 309-326, ISSN: 1751-7656

The low submerged unit weights of peats usually lead to low effective self-weight stresses, stiffnessesand undrained shear strengths. These features, in combination with high compressibility, a propensityto creep and the uncertain effects of fibrous inclusions, make foundation stability hard to assessreliably. It is usual to apply high safety, or strong material reduction, factors in foundation design.However, over-conservatism can lead to undesirable environmental and financial costs. This paperdescribes full-scale field tests conducted on peat, with and without pre-loading, at Uitdam on theborders of Lake Markermeer, north of Amsterdam. The experiments investigated the peat layers’consolidation behaviour and their response under loading, including full shear failure. Noting thecomplex final test geometries and the large displacements developed, simple numerical analyses wereundertaken to help interpret the failures within a Tresca and ‘consolidated undrained shear strength’framework. The trials that included modest pre-loading developed large vertical consolidation strains(up to 35%) and significant bearing capacity improvements. The field experiments provide a richresource for testing advanced numerical techniques. They also allowed a range of practical characterisationtechniques to be assessed and calibrated for flood dyke applications.

Journal article

Barbosa P, Geduhn M, Jardine R, Schroeder F, Horn Met al., 2015, Full scale offshore verification of axial pile design in chalk, Pages: 515-520

© 2015 Taylor & Francis Group, London. Iberdrola is developing the Wikinger offshore windfarm in the German Baltic Sea. The wind turbines will be supported by four legged jackets founded on driven open ended steel piles. Loading will be predominantly axial with shaft resistance governing design. Ground conditions over much of the project area comprise of thick Chalk layers. A review of current pile design methods for Chalk and related onshore pile test campaigns highlighted significant design uncertainties and led to a decision to conduct dynamic and static offshore pile tests at the site. This paper summarizes the aims and rationale of the tests carried out in late 2014, describes the design of the remotely operated testing arrangements and reports on an associated research project that is advancing in conjunction with Imperial College London and Geotechnical Consulting Group.

Conference paper

Barbosa P, Geduhn M, Jardine R, Schroeder F, Horn Met al., 2015, Offshore pile load tests in Chalk, Pages: 2885-2890

© The authors and ICE Publishing: All rights reserved, 2015. Iberdrola is developing the Wikinger offshore windfarm in the German Baltic Sea. Wind turbines are supported by four legged jackets founded on driven open ended steel piles. Loading will be predominantly axial with shaft resistance governing design. Ground conditions over much of the project area comprise of thick Chalk layers. A review of current pile design methods and related onshore pile test campaigns highlighted significant design uncertainties and led to a decision to conduct dynamic and static offshore pile tests. This paper summarizés the aims and rationale of the tests carried out in late 2014, describes the design of the remotely operated testing arrangements and reports on an associated research project that is advancing with Imperial College London and Geotechnical Consulting Group.

Conference paper

Rimoy SP, Jardine RJ, 2015, Analysis of an extended field test database regarding driven pile ageing in sands, Pages: 1157-1162

© The authors and ICE Publishing: All rights reserved, 2015. Field testing has revealed that the axial capacities of piles driven in sand can increase dramatically with age after driving. Jardine et al (2006) showed from experiments conducted in Dunkirk that the processes are affected by the history of prior loading and assembled a modest database of field cases to support the evidence from their single test site. This paper reports an extended database that is used to assess: The distinct contributions of base and shaft loads; the potential influence of loading sign (compression or tension); the effects of any prior failures; the influence of groundwater type as well as the effects of pile diameter and material. The analysis presented is informed by parallel highly instrumented model tests that were designed to explore the fundamental driving mechanisms. The findings have important implications for the re-assessment and re-use of foundations in a wide range of onshore and offshore project settings.

Conference paper

Zwanenburg C, Jardine RJ, 2015, The characterisation of operational shear strength for peats through full scale trials combined with laboratory and field testing, Pages: 2455-2460

© The authors and ICE Publishing: All rights reserved, 2015. Full scale, heavily-instrumented, field tests were conducted on peat to find operational foundation shear strength parameters for flood protection dikes that run through an area of outstanding beauty. The low submerged unit weights of peats usually lead to very low effective stresses, stiffness and uncertain undrained shear strengths. The loading tests, which were conducted both with and without preloading, provided guidance on these key questions. Shear failures were induced and even modest pre-loading was shown to generate both large vertical strains and significant bearing capacity improvements. The research also provided an opportunity to check and calibrate a range of laboratory and field characterisation techniques, leading to the broad set of conclusions summarised in the paper.

Conference paper

Byrne BW, McAdam R, Burd HJ, Houlsby GT, Martin CM, Zdravković L, Taborda DMG, Potts DM, Jardine RJ, Sideri M, Schroeder FC, Gavin K, Doherty P, Igoe D, Muirwood A, Kallehave D, Skov Gretlund Jet al., 2015, New design methods for large diameter piles under lateral loading for offshore wind applications, Pages: 705-710

© 2015 Taylor and Francis Group, London. Offshore wind turbines are typically founded on single large diameter piles, termed monopiles. Pile diameters of between 5mand 6mare routinely used, with diameters of up to 10 m, or more, being considered for future designs. There are concerns that current design approaches, such as the p − y method, which were developed for piles with a relatively large length to diameter ratio, may not be appropriate for large diameter monopiles. A joint industry project, PISA (PIle Soil Analysis), has been established to develop new design methods for large diameter monopiles under lateral loading. The project involves three strands of work; (i) numerical modelling; (ii) development of a new design method; (iii) field testing. This paper describes the framework on which the new design method is based. Analyses conducted using the new design method are compared with methods used in current practice.

Conference paper

Jardine RJ, Thomsen NV, Mygind M, Liingaard MA, Thilsted CLet al., 2015, Axial capacity design practice for North European wind-turbine projects, Pages: 581-586

© 2015 Taylor & Francis Group, London. Improving foundation design is central to the offshore wind industry developing deeper water sites. This paper reviews the technical and regulatory difficulties for design of axially loaded piles to German offshore windfarm projects. It is argued that moving towards reliable forward predictive pile design methods and away from ‘dynamic proving tests’ will be vital to reducing unnecessarily high material and installation costs, installation risks and disturbance to marine mammals. Steps are outlined to implement such a change either in combination with regional or international load and resistance factors.

Conference paper

Zdravković L, Taborda DMG, Potts DM, Jardine RJ, Sideri M, Schroeder FC, Byrne BW, McAdam R, Burd HJ, Houlsby GT, Martin CM, Gavin K, Doherty P, Igoe D, Muirwood A, Kallehave D, Skov Gretlund Jet al., 2015, Numerical modelling of large diameter piles under lateral loading for offshore wind applications, Pages: 759-764

© 2015 Taylor and Francis Group, London. There is currently a significant focus on developing offshore wind power in the UK and Europe. The most common foundation type for wind turbines is a single large diameter pile, termed a monopile, on which the turbine is located. As the diameter of such piles is envisaged to increase in future installations, there are concerns that current design methods are not applicable. To explore this problem, the joint industry project PISA has been established, with the aim to develop a new design framework for laterally loaded piles utilised in the offshore wind industry, based on new theoretical developments, numerical modelling and large scale field pile testing. This paper presents an overview of numerical modelling undertaken as part of the project.

Conference paper

Rimoy SP, Jardine RJ, 2015, Axial capacity ageing trends of piles driven in silica sands, Pages: 637-642

© 2015 Taylor and Francis Group, London. Field studies of piles driven in silica sands have shown axial capacity increases (set-up) over the days to months that follow driving, long after installation induced pore pressures have dissipated. Three main hypotheses have been proposed regarding the governing mechanisms and tested to a limited extent through relatively modest databases of pile load tests. However, a secure understanding of the governing mechanisms is required before projecting ageing predictions for other cases and considering how ageing trends might be affected by, for example, scale, pile type, groundwater regime or submerged offshore conditions. This paper reports an extended database study aimed at assessing the distinct ageing contributions of base and shaft loads, the potential influence of compression or tension axial loading directions, the effects of prior loading history, the influence of groundwater type as well as the effects of pile diameter and material. The analysis is informed by parallel highly instrumented model tests that were designed to investigate and identify the fundamental ageing mechanisms. The findings have important implications for pile design and re-assessment.

Conference paper

Tsuha CDHC, Jardine RJ, Yang Z, Silva M, Rimoy Set al., 2015, Advanced laboratory investigation of axial cyclic loading in silica sands, 6th International Symposium on Deformation Characteristics of Geomaterials, Publisher: IOS PRESS, Pages: 866-873

Conference paper

Yang ZX, Jardine RJ, Zhu BT, Rimoy Set al., 2014, Stresses Developed around Displacement Piles Penetration in Sand, JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING, Vol: 140, ISSN: 1090-0241

Journal article

Jardine RJ, 2014, Advanced laboratory testing in research and practice: The 2nd Bishop Lecture, Geotechnical Research, Vol: 1, Pages: 2-31

This paper demonstrates the special capabilities and practical value of advanced laboratory testing, focusing on its application in advancing the understanding and prediction of how driven piles function and perform in sand. Emphasis is placed on integrating laboratory research with analysis and field observations, drawing principally on work by the author, his colleagues and research group. The laboratory studies include highly instrumented static and cyclic stress-path triaxial experiments, hollow cylinder and ring-shear interface tests and micro-mechanical research. Soil element testing is combined with model studies in large laboratory calibration chambers, full-scale field investigations and numerical simulations to help advance fundamental methods for predicting pile behaviour that have important implications and applications, particularly in offshore engineering.

Journal article

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