Driven Pile Behaviour in Low-to-Medium Density Chalk: the ALPACA JIP Outcomes

Jardine, R., Buckley, R. , Liu, T., Byrne, B., Kontoe, S., McAdam, R., Schranz, F. and Vinck, K. (2023) Driven Pile Behaviour in Low-to-Medium Density Chalk: the ALPACA JIP Outcomes. In: 9th International SUT OSIG Conference “Innovative Geotechnologies for Energy Transition”, London, UK, 12-14 Sep 2023,

Abstract

Offshore pile design presents multiple challenges in low-to-medium density chalks, whose sensitivity and brittleness often leads to very low driving resistances. Also, existing design rules have proved unable to give reliable predictions for axial and lateral resistances under offshore field loading conditions. This paper summarises how the ALPACA and ALPACA Plus Joint Industry Projects (JIPs) addressed the current lack of knowledge through comprehensive field, laboratory and theoretical research. Axial and lateral field tests were conducted, under dynamic, cyclic and monotonic conditions, on 43 piles with diameters between 139mm and 1.8m, made with a range of materials, wall thicknesses and tip conditions, driven to depths between 3 and 18m. Over 100 tests were completed, after ageing for up to 400 days. Most test piles were instrumented with robust fibre-optic strain gauge systems. The experiments were supported by intensive in-situ and laboratory stress-path and cyclic testing. New monotonic and cyclic axial design methods developed for the JIP represent field behaviour far better than existing approaches. Important new observations were also made regarding pile behaviour under cyclic lateral loading, while the monotonic lateral pile tests were interpreted to generate ‘p-y’ load reaction curves and test more advanced 3-D FE approaches, developed through parallel research.

• Item Type: Conference Proceedings
• Additional Information: The Authors gratefully acknowledge support from UK grants from EPSRC (EP/P033091/1), Royal Society (NA160438) and Supergen ORE Hub 2018 (EPSRC EP/S000747/1). Byrne is supported by the Royal Academy of Engineering under the Research Chairs and Senior Research Fellowships scheme, while Vinck was supported by EPSRC Grant EP/L016826/1, DEME and Imperial College.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Buckley, Dr Roisin
• Authors: Jardine, R., Buckley, R., Liu, T., Byrne, B., Kontoe, S., McAdam, R., Schranz, F., and Vinck, K.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment

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