Work by Socotec, Imperial College London and Oxford University under a grant from the Engineering and Physical Sciences Research Council (EPSRC) and industry partners to develop a high precision pile load testing system has been showcased.
The axial-lateral pile analysis for Chalk applying multi-scale field and laboratory testing – known as Alpaca – was demonstrated by Socotec at a quarry near Margate, Kent last week to the project’s 12 industry partners.
The aim of the Alpaca project, which started in October last year, is to improve the reliability of predicting the capacity of large piles driven in difficult ground conditions such as Chalk. The Alpaca project aims to rectify the poor state of knowledge, building on an earlier Joint Industry Project involving Scottish Power Renewables, Iberdrola, Imperial College and Geotechnical Consulting Group. The Alpaca project team is aiming to develop new driven pile design guidance for chalk sites through a comprehensive programme of high quality field tests, advanced laboratory testing, rigorous analysis and synthesis with other case history data.
Socotec has said that the research streams being undertaken through the current project include field testing and chalk characterisation as well as the advanced laboratory analysis to support the synthesis of data.
To support the project, Socotec prepared steel tubular piles with FBG fibre optic strain gauges to allow dynamic strain measurements during driving and subsequently under maintained load testing. Each instrumented pile has two strings diametrically opposite each other to monitor eccentricity during driving and distribution of strain under load. The fibres are pre-tensioned and laid in shallow grooves along the external surface of the tubular pile.
Socotec is understood to be the first company to use such technology in the UK.
“We’re extremely proud to be involved with such a large scale pile testing research project,” said Socotec operations director for foundation testing Martyn Ellis. “The open day provided us with an opportunity to demonstrate what we do best to a key audience. We look forward to continuing our developments and support for this project which brings together businesses and academics alike.”
The current research stage involves Socotec undertaking high precision pile load testing including tension, compression, lateral and cyclic technology as part of ground breaking research work in chalk strata for the wind energy industry.