Displacement pile behaviour in glacial clay

Lehane, Barry; Jardine, R. J.

doi:10.1139/t94-009

Cited by 59 publications

(25 citation statements)

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“…This can be seen in the work of Marsland & Powell (1980), who, carrying out a series of large-diameter cyclic plate load tests in the same till deposit, showed that there was no significant change in ultimate capacity measured by CRP testing after cyclic loading, but there was an overall stiffening of response in the pre-yield phase. Lehane & Jardine (1994), testing model jacked-in displacement piles at the same site, concluded that retesting the piles resulted in alteration of the soil fabric, described as plastic hardening, with radial effective stresses being approximately 15% higher in all retests. However, the relative disturbance of the soil fabric is likely to be greater for a displacement pile than for the auger-bored pile described here.…”

Section: Analysis Of Rapid Load Tests In Glacial Tillmentioning

confidence: 99%

Analysis of a rapid load test on an instrumented bored pile in clay

2006

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Rapid load testing methods for piled foundations are generally easier and quicker to mobilise than classic static tests, and are less complex to analyse than dynamic load tests. A recently developed rapid load pile testing method known as the Statnamic test is seeing greater use in the UK for the assessment of piles. For foundation design, it is necessary to derive the equivalent static load-settlement curve from the rapid load test data by eliminating inertial and damping effects. Existing methods of test analysis generally provide good correlation with static tests for sands and gravels, but overpredict pile capacities by up to 50% for clays. In order to gain an insight into the behaviour of rapid load pile testing in clays, a full-scale pile instrumented with accelerometers, strain-gauged sister bars and a tip load cell was tested in a glacial lodgement till near Grimsby, UK. The soil around the pile was also instrumented with radially arrayed buried accelerometers. The test pile was subjected to rapid loading tests, the results of which were compared with constant rate of penetration and maintained load static tests on the same pile. Results from the field testing have been analysed using non-linear viscous parameters obtained from laboratory model and element tests to represent rate-dependent clay shear resistance in the post-yield phase of loading. Shaft frictions derived from the strain-gauged reinforcement in the pile have been compared with shear strains and stresses derived from accelerations in the surrounding soil to give an insight into the load transfer mechanisms for a rapidly loaded pile in clay.

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Section: Analysis Of Rapid Load Tests In Glacial Tillmentioning

confidence: 99%

Analysis of a rapid load test on an instrumented bored pile in clay

2006

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“…It is apparent that additional testing of large diameter, high capacity piles ,where radial effective stresses are measured throughout installation, equalisation and load-testing, is required in order to address many of the uncertainties that remain in current pile design methods. Undrained Strength, s u (kPa) Adhesion Factor, α Tomlinson(1957) Peck (1958) Woodward (1961) Kerisel ( Tomlinson(1957)   λ approach, Vijayvergiya and Focht (1972)   API 1(1976API 1( -1986   API 2(1976API 2( -1986   Semple and Rigden (1984)   Randolph and Murphy (1985)   API(1987-Present)   Kolk & van der Velde (1996)   NGI-99, Karlsrud et al (2005)   Lehane and Jardine (1994a) Bothkennar Low OCR shallow marine clay Lehane and Jardine (1994b) Pentre Low OCR Glacio-Lacustrine silty clay Chow (1997) …”

Section: Discussionmentioning

confidence: 99%

The Shaft Capacity of Displacement Piles in Clay: A State of the Art Review

Doherty

Gavin

2011

Geotech Geol Eng

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The rapid expansion of the offshore wind sector, coupled with increasing demand for high rise structures, has placed renewed demand on the driven piling market.In light of this industry growth, this paper reviews the evolution of design approaches for calculating the shaft capacity of displacement piles installed in cohesive soils. The transition from traditional total stress design towards effective stress methods is described. Complex stress-strain changes occur during pile installation, equalisation and load testing and as a consequence, the selection of parameters for use in conventional earth-pressure type effective stress approaches is not straight-forward. These problems have led to the development of empirical correlations between shaft resistance and in-situ tests, such as the cone penetration tests. However, many of these approaches are limited because they were developed for specific geological conditions. Significant insight into pile behaviour has been obtained from recent model pile tests, which included reliable measurements of radial effective stresses. These tests have allowed factors such as friction fatigue and interface friction to be included explicitly in design methods.Whilst analytical methods have been developed to investigate pile response, these techniques cannot yet fully describe the complete stress-strain history experienced by driven piles. The use of analytical methods in examining features of pile behaviour, such as the development of pore pressure during installation and the effects of pile end geometry on pile capacity, is discussed.2

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“…Both onshore test sites have extensive histories of pile testing activities (e.g. Lehane and Jardine, 1994;Chow, 1997;Jardine et al, 2006), and consequently the sites have been reasonably characterised through field testing and laboratory experiments (e.g. Powell and Butcher, 2003).…”

Section: Sites and Characterisationmentioning

confidence: 99%

PISA: New Design Methods for Offshore Wind Turbine Monopiles

Byrne

McAdam

Burd

et al.

Offshore Site Investigation Geotechnics 8th International Conference Proceedings

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Improved design of laterally loaded monopiles is central to the development of current and future generation offshore wind farms. Previously established design methods have demonstrable shortcomings requiring new ideas and approaches to be developed, specific for the offshore wind turbine sector. The Pile Soil Analysis (PISA) Project, established in 2013, addresses this problem through a range of theoretical studies, numerical analysis and medium scale field testing. The project completed in 2016; this paper summarises the principal findings, illustrated through examples incorporating the Cowden stiff clay profile, which represents one of the two soil profiles targeted in the study. The implications for design are discussed.

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Displacement pile behaviour in glacial clay

Cited by 59 publications

References 0 publications

Analysis of a rapid load test on an instrumented bored pile in clay

Analysis of a rapid load test on an instrumented bored pile in clay

The Shaft Capacity of Displacement Piles in Clay: A State of the Art Review

PISA: New Design Methods for Offshore Wind Turbine Monopiles

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