Enhanced stress wave analysis of scaled monopiles in glacial till at Cowden

Conventional stress wave analysis for pile driving involves a subjective signal matching process using pile driving
analyser (PDA) measurements. The PICASO (PIle Cyclic AnalySis: Oxford and Ørsted) research project provided an
opportunity to collect high frequency strain measurements using optical fibre Bragg grating (FBG) sensors over the
embedded length of the pile, in addition to conventional PDA data. This paper reports the application of a novel hybrid
approach incorporating FBG data into the signal matching process, as developed by Buckley et al. (2020a), to an overconsolidated
glacial till site in Cowden, Hull, UK. The additional information on stress wave propagation, obtained
through FBG measurements, provides insights into the development of soil resistance to driving (SRD) in stiff clays.
The results obtained using the new framework are compared to the resistance predicted using a widely-adopted
empirical method.