Bridgwater Tidal Barrier Phase 2 Ground Investigation | Causeway Geotech Ltd

Project Title:

Date:

September to December 2019

Location:

Bridgwater, Somerset, England

Client:

The Environment Agency / BAM Nuttall

Business Sectors:

Environment (Flood Defence)

Services (Technical Disciplines):

The completion of land and overwater ground investigation works, including cable percussion boring, rotary drilling, static cone penetration tests and trial pitting. Overwater works were completed off a jack-up barge, with a series of temporary floating walkways installed from the riverbank to allow access and egress to the working platform at all states of the tide.

Project Objectives/ Outcomes:

Causeway Geotech were appointed by BAM Nuttall Ltd on behalf of the Environment Agency to carry out land and overwater ground investigation works for provision of geotechnical and environmental information to characterise ground conditions at the site of the proposed Bridgwater Tidal Barrier for input to the design and construction phase.

The success of this project relied heavily on good communication between all parties; works carried out under the supervision of a full time Site Agent and two designated Site Engineers (1 land and 1 marine) from Causeway Geotech.

The River Parrett feeds the Bristol Channel and has the second highest tidal range in Europe; bespoke access solutions were required to ensure overwater works could continue uninhibited.

The contract was completed on time and on budget to the satisfaction of all involved stakeholders. The construction phase is due to commence in Q3 2022 following public consultation.

Our Role:

This was an Early Contractor Involvement (ECI) where the Principal Contractor (BAM Nuttall Ltd) appointed Causeway Geotech on behalf of their Client (Environment Agency) with the scheme Designer (Jacobs UK) acting as Investigation Supervisor.

The scope of works included:

4 overwater boreholes by cable percussion boring and Geobor S wireline follow-on coring
4 overwater Cone Penetration Tests
Overwater works conducted off a C5 jack-up barge
12 land-based boreholes by a combination of cable percussion boring and Geobor S wireline coring
14 boreholes by dynamic sampling methods
29 land-based Cone Penetration Tests
In-situ testing including packer tests, HPD tests, borehole permeability tests and indirect CBRs by DCP
40 trial pits by mechanical excavator
Factual ground investigation report.

Geoscience Ireland Contact:

Darren O’Mahony (Darren.omahony@causewaygeotech.com)