Since the 1990s, GCG has served as the Specialist Geotechnical Advisor to Crossrail Ltd, supporting the project through every phase—from early scheme development and Parliamentary approval to detailed design and construction.
Our wide-ranging role included:
- Feasibility and Option Studies
Evaluating ground-related risks and informing early design decisions. - Ground Movement and Building Damage Assessments
Predicting and mitigating the impact of tunnelling and excavation on existing structures. - Ground Investigation and Monitoring
Specifying, supervising, and interpreting extensive site investigations and construction monitoring. - Centralised Data Management
Developing and managing comprehensive databases for ground investigation and groundwater monitoring data. - Technical Authority and Expert Panel Involvement
GCG staff were seconded into the Crossrail client team, acting as Technical Authority for geotechnical design and construction across the eastern alignment. We also contributed to an expert panel advising on project-wide geotechnical strategy. - Temporary Works and Construction Risk Management
Providing close support on complex and high-risk elements of construction, including temporary works. - Geotechnical Baseline Reports (GBRs)
GCG pioneered a novel and effective GBR format for Crossrail, producing or reviewing all 34 GBRs across the project. These reports covered a wide range of construction techniques—EPB and slurry TBMs, sprayed concrete lining, diaphragm walls, piling, and ground improvement—often in challenging ground conditions beneath the London Clay.
A post-construction review revealed the effectiveness of this GBR approach: compensation event claims related to GBRs accounted for less than 0.4% of the total value of the contracts that included them—demonstrating the value of clear, well-founded geotechnical baselines in managing risk and cost.
Publications
J.A. Davis (2017) Crossrail’s Experience of Geotechnical Baseline Reports, in press – see: The Crossrail Project, Infrastructure Design and Construction Vol 4, 2017 http://learninglegacy.crossrail.co.uk/article-author/john-davis/
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