Geotechnical Design

CGL's Geotechnical Design Engineers working on GCI modelling

Our Geotechnical Design team at CGL has strong design and engineering expertise for temporary and permanent works including foundations, retaining walls and earthworks.

We can use a range of analytical software systems to predict soil-structure interaction with a high degree of accuracy enabling us to design appropriate solutions to the risks faced at a particular site. By exploring non-conventional and innovative solutions with the support of advanced numerical analysis software we have often added value engineering to projects for our clients.

CGL’s Geotechnical Design services include:

  • Detailed ground movement analysis and impact assessments
  • Foundation and substructure designs
  • Retaining wall design
  • Groundwater flow and seepage analysis
  • Slope stability analysis and design
  • Earthworks design and control
  • Observational approach and monitoring strategies
  • Construction sequencing
  • Basement temporary propping systems
  • Basement Impact Assessment

Value engineering

We are proud to have won awards for our innovative approach, which often reduces cost, risk, uncertainty or timescale in construction projects.

Analytical resources

Our soil-structure interaction analysis of foundation options has enabled the removal of pile foundations from designs and substituted them by more conventional raft foundations with associated benefits of decreased cost and programme time. We have also designed numerous pile-raft foundations to eliminate the need for large diameter and deep conventional piles through difficult ground conditions, including the reuse of existing piles where relevant.

Where piled walls have been proposed in competent soils, our detailed analysis and implementation of observational methods have allowed the replacement of such elements with open-cut slopes and king posts, even adjacent to sensitive railway infrastructure.

We also carry out ground movement analysis to assess the impact of retaining wall installation, basement excavation, retaining wall deflection and foundation loading on site constraints such as neighbouring structures (often listed buildings), Network Rail, National Grid, London Underground and Thames Water infrastructure. These often require rigorous checking and approvals processes.

Depending on the complexity, our analysis and designs are undertaken using conventional (WALLAP, PDISP, GWALL) or advanced numerical (FLAC 2D and PLAXIS 3D) analysis software, or if required a combination of both.


Our geotechnical work has been recognised by a series of Ground Engineering awards including:

  • 2020 Finalist for Technical Excellence – The Evolving Buttress Pile Solution
  • 2020 Finalist for UK Project with a Geotechnical Value of Between £0.5m and Under £1m – Potters Lea
  • 2019 Winner for UK Project with a Geotechnical Value up to £1M for our value-engineered piled raft solution at 27 Commercial Road
  • 2018 Finalist for Technical Excellence for work to enable the use of buttress piles for efficient deep basement construction at Prince of Wales Drive
  • 2018 Finalist for Project of the Decade for the deep basement at the Guildford Radisson Hotel 
  • 2017 Finalist for UK Project with a Geotechnical Value between £1-3m for our temporary and permanent works designs at Seymour Street
  • 2017 Finalist for UK Project with a Geotechnical Value up to £1m for our innovative piling design at Miles Street
  • 2016 Winner of Best UK Project with a Geotechnical Value between £1-3mSubsea 7 Office


Related Geotechnical Design Projects