Measurements of distributed strain during impact pile driving

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Title: Measurements of distributed strain during impact pile driving
Authors: Buckley, R
Byrne, BW
Doherty, JP
Jardine, R
Kontoe, S
McAdam, RA
Randolph, MF
Item Type: Conference Paper
Abstract: This paper reports the use of optical Fibre Bragg Grating (FBG) sensors to monitor the stress waves generated below ground during pile driving, combined with measurements using conventional pile driving analyzer (PDA) sensors mounted at the pile head. Fourteen tubular steel piles with a diameter of 508 mm and embedded length to diameter ratios of 6 to 20 were impact driven at an established chalk test site in Kent, UK. The pile shafts were instrumented with multiple FBG strain gauges and pile head PDA sensors, which monitored the piles’ responses under each hammer blow. A high frequency (5 kHz) fibre optic interrogator allowed a previously unseen resolution of the stress wave propagation along the pile. Estimates of the base soil resistances to driving and distributions of shaft shear resistances were found through signal matching that compared time series of pile head PDA measurements and FBG strains measured below ground surface. Numerical solutions of the one-dimensional wave equation were optimised by taking account of the data from multiple FBG gauges, leading to significant advantages that have potential for widespread application in cases where high resolution strain measurements are made.
Date of Acceptance: 24-Mar-2020
DOI: 10.1680/pttc.65048.217
ISBN: 978-0-7277-6504-8
Publisher: ICE Publishing
Journal / Book Title: Piling 2020: Proceedings of the Piling 2020 Conference
Copyright Statement: © The Authors 2021. Published by ICE Publishing.
Sponsor/Funder: Engineering & Physical Science Research Council (E
Scottishpower Renewables (UK) Limited
Equinor Energy AS
Siemens Gamesa Renewable Energy A/S
Innogy SE
Eoliennes en Mer Dieppe Le Transport
Parkwind NV
Funder's Grant Number: EP/P033091/1
PO No: 4300010104
N/A (Linked to: EP/P033091/1)
Conference Name: Piling 2020
Publication Status: Accepted
Start Date: 2021-03-23
Finish Date: 2021-03-26
Conference Place: online
Embargo Date: 2022-03-04
Online Publication Date: 2021-03-05
Appears in Collections:Civil and Environmental Engineering