343 results found
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.
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.
Rimoy S, Silva M, Jardine R, et 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.
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.
Yang ZX, Jardine RJ, Zhu BT, et al., 2014, Stresses Developed around Displacement Piles Penetration in Sand, JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING, Vol: 140, ISSN: 1090-0241
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.
Kamal RH, Coop MR, Jardine RJ, et al., 2014, The post-yield behaviour of four Eocene-to-Jurassic UK stiff clays, GEOTECHNIQUE, Vol: 64, Pages: 620-634, ISSN: 0016-8505
Zhang C, Yang ZX, Nguyen GD, et al., 2014, Theoretical breakage mechanics and experimental assessment of stresses surrounding piles penetrating into dense silica sand, GEOTECHNIQUE LETTERS, Vol: 4, Pages: 11-16, ISSN: 2049-825X
Gasparre A, Hight DW, Coop MR, et al., 2014, The laboratory measurement and interpretation of the small strain stiffness of stiff clays, Geotechnique, Vol: 64, Pages: 942-953, ISSN: 0016-8505
Silva M, Foray P, Rimoy S, et al., 2013, Influence of cyclic axial loads on the behaviour of piles driven in sand, Paris, TC-209 Workshop, ‘Design for cyclic loading: piles and other foundations’, Publisher: Presses des Ponts, Pages: 81-84
Puech A, Benzaria O, Thorel L, et al., 2013, Cyclic stability diagrams for piles in sands, Paris, TC-209 Workshop, ‘Design for cyclic loading: piles and other foundations’, Publisher: Presses des Ponts, Pages: 85-88
Andersen KA, Puech AA, Jardine RJ, 2013, Cyclic resistant geotechnical design and parameter selection for offshore engineering and other applications, Paris, TC-209 Workshop, ‘Design for cyclic loading: piles and other foundations’, Publisher: Presses des Ponts, Pages: 9-44
Jardine RJ, 2013, Advanced laboratory testing in research and practice. 2nd Bishop Lecture, 18th Conf. on Soil Mechanics and Geotechnical Engineering, Publisher: Presses des Ponts, Pages: 25-55
Silva M, Foray P, Rimoy S, et al., 2013, Influence des chargements cycliques axiaux sur le comportement et la capacité des pieux foncés dans les sables., Proc. 18th Int. Conf. on Soil Mechanics and Geotechnical Engineering, Publisher: Presses des Ponts, Pages: 2403-2406
Nishimura S, Jardine RJ, Fenton CH, et al., 2013, Development of a predictive framework for geothermal and geotechnical responses in cold regions experiencing climate change, Paris, 18th Int. Conf. on Soil Mechnics and geotechnical Engineering, Publisher: Presses des Ponts, Pages: 3391-3394
Rimoy S, Jardine RJ, Standing JR, 2013, Displacement response to axial cycling of driven piles in sand, 18th Int. Conf. on Soil Mechanics and Geotchnical Engineering, Publisher: Presses des Ponts, Pages: 2387-2390
Rimoy SP, Jardine RJ, Standing JR, 2013, Displacement response to axial cycling of piles driven in sand, ICE Proceedings Geotechnical Engineering
Jardine RJ, Zhu BT, Foray P, et al., 2013, Interpretation of stress measurements made around closed-ended displacement piles in sand, GEOTECHNIQUE, Vol: 63, Pages: 613-627, ISSN: 0016-8505
Silva M, Foray P, Rimoy S, et al., 2013, Influence of cyclic axial loads in the behaviour and response of driven piles in sand, Pages: 2403-2406
This paper presents a new cyclic stability diagram for the lateral friction and the effect on the tensile capacity of instrumented model piles subjected to axial cyclic loading across a wide range of calibration chamber testing in silica sand. Local measurements of stresses in the soil mass (vertical, radial and orthoradial) at different distances from the axis of the pile, as well as shear and radial stresses at the soil-pile interface, provide a detailed analysis of the evolution of local stress paths around the pile and the soil mass during cyclic and post-cyclic loading.
Jardine RJ, 2013, Bishop Lecture Advanced laboratory testing in research and practice, 18th International Conference on Soil Mechanics and Geotechnical Engineering (18th ICSMGE), Publisher: PRESSES DES PONTS, Pages: 35-54
Puech A, Benzaria O, Thorel L, et al., 2013, Cyclic stability diagrams for piles in sands, Pages: 2379-2382
This paper gathers cyclic stability diagrams obtained from various experimental sources: in situ tests on actual piles, laboratory tests on model piles in a large calibration chamber and model piles in a centrifuge. Driven piles in tension and bored piles in compression are addressed. Cyclic stability diagrams are useful tools for a preliminary assessment of the effects of cyclic loadings on the behaviour of piles.
Jardine RJ, Zhu BT, Foray P, et al., 2013, Measurement of Stresses around Closed-Ended Displacement Piles in Sand, Geotechnique, Vol: 63, Pages: 1-17
Jardine RJ, Aghakouchak A, Sim WW, 2013, Cyclic triaxial tests to aid offshore pile analysis and design, Proceedings of the ICE - Geotechnical Engineering, Vol: 166, Pages: 111-121, ISSN: 1353-2618
Renewable offshore energy structures experience unusually high levels of cyclic loading under storm and operating conditions. Laboratory and full-scale tests provide one route to develop rational foundation design approaches for such structures. Analytical approaches may also be developed from soil element testing and modelling. This paper outlines preliminary results from such a study. Computer-controlled stress path triaxial equipment, employing high-resolution local strain instrumentation, is adopted for experiments on Dunkerque and Fontainebleau sands designed to support parallel full-scale field and laboratory-model testing programmes involving axial pile loading. The triaxial experiments comprise suites of constant-volume uniform cyclic tests on K 0 over-consolidated specimens employing different amplitudes, performed in conjunction with static and multi-stage experiments that examine the effects of non-uniform cyclic loading. Preliminary results reveal the relationships between cyclic deviator stress, mean effective stress changes and number of cycles, as well as patterns of permanent and cyclic strain development.
Puech A, Benzaria O, Thorel L, et al., 2013, Diagrammes de stabilité cyclique de pieux dans les sables, Paris, 18th Int. Conf. on Soil Mechanics and Geotechnical Engineering, Publisher: Presses des Ponts, Pages: 2379-2382
Jardine RJ, Andersen K, Puech A, 2012, Keynote Paper. Cyclic loading of offshore piles: potential effects and practical design., London, 7th International Conference on Offshore Site Investigations and Geotechnics, Publisher: Society for Underwater Technology, Pages: 59-100
Carneiro A, Jardine RJ, 2012, A model study of how pre-drilling affects displacement pile capacity in stiff clays, London, 7th International Conference on Offshore Site Investigations and Geotechnics, Publisher: Society for Underwater Technology, Pages: 473-480
Merritt A, Schroeder F, Jardine RJ, et al., 2012, Development of pile design methodology for an offshore wind farm in the North Sea, London, 7th International Conference on Offshore Site Investigations and Geotechnics, Publisher: Society for Underwater Technology, Pages: 439-448
Rimoy SP, Jardine RJ, Silva M, et al., 2012, Local and global behaviour of cyclically loaded instrumented model displacement piles in sand, London, 7th International Conference on Offshore Site Investigations and Geotechnics, Publisher: Society for Underwater Technology, Pages: 279-286
Puech A, Canou J, Bernardini C, et al., 2012, SOLCYP: a four-year JIP on the behaviour of piles under cyclic loading, London, 7th International Conference on Offshore Site Investigations and Geotechnics, Publisher: Society for Underwater Technology, Pages: 263-270
Carneiro A, 2012, A model study of how pre-drilling affects displacement pile capacity in stiff clays., London, 7th International Conference on Offshore Site Investigations and Geotechnics, Publisher: Society for Underwater Technology, Pages: 473-480
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