Nearshore GI at Naver Bridge

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Highland Council

Client’s Representative



Site Operations


October 2021 – February 2022

Awarded Ground Investigation Project of the Year by Ground Engineering Awards 2022!


Project Summary

Causeway Geotech were appointed by The Highland Council to carry out a nearshore ground investigation for the provision of geotechnical and environmental information to characterise ground conditions at the proposed replacement bridge.

The construction of the replacement bridge required investigation of the superficial soils geology to progress the design and construction of this bridge.

Siteworks were carried out under the supervision of Site Engineers from Causeway Geotech who liaised with Client’s Representatives to ensure all aspects of the works were completed safely and as per the project requirements.

Liaising with the council, ecological consultants and the local community proved invaluable to coordinate works and barge moves ensuring a safe working practice and all environmental mitigation protocols were in place.

This contract required careful planning from inception to delivery due to the  remote location, stringent environmental restrictions, and high HSQE standards required by a project of this nature.

The technical challenges faced were very dense gravels and cobble/boulders to depths of 50m bgl which we were able to overcome using our experience with sonic drilling techniques from other marine projects. This proved difficult the at the beginning of works, however we were able to fine tune our drilling techniques to attain excellent recovery and improved drill run times.  Rock coring was especially difficult, but again by carrying a broad stock of drill bits, we were able to react to different rock types and ensure continued penetration.

Another significant challenge faced was the remote set up of the barge being constructed on a tidal river near an existing bridge in an area of limited space, as well as being on the bounds of an SAC. With our careful planning and utilising trusted subcontractors this project was a huge success, completed safely and ahead of schedule.

Project Scope

overwater boreholes by sonic boring and GeoBor S wireline coring

boreholes by sonic drilling sampling methods (land)

road pavement cores