A82 – Tarbet to Inveraran
Transport Scotland propose to widen the existing A82 Tarbet to Inverarnan section. The works will improve road-use experience on this priority route. A complex ground investigation was required to support the design process.
The £3.4M ground investigation for the A82 upgrade had to contend with steeper slopes, deeper bogs and narrower access than many other projects of this scale. Whilst it was one of the largest and most challenging ground investigations undertaken by Soil Engineering in Scotland, it was also one of the most varied with a wide range of both geophyscial and intrusive techniques required. The design will incorporate new structures including viaducts, shoreline works and drainage improvements.
At the peak of work, Soil Engineering had a team of 35 people on site. Overwater works were undertaken from two pontoons equipped with both Rotary and Cable Percussive drilling rigs, and full welfare facilities. A land-based team simultaneously completed Rotary and Cable Percussive works. A total of almost 150 boreholes were completed during the works, to depths of up to 40m below ground level. Also completed within the scope were 38No. machine and hand excavated trial pits, 208No. pavement cores and in excess of 1400 peat probes. In situ testing included geophysical surveys, televiewer surveys, dynamic cone penetrometer tests, variable head tests, hand vane tests, and soak-away tests. Due to restricted access times and conditions on areas of the site Sonic Drilling and Slope Climbing rigs were employed to minimise works impacts on stakeholders.
The challenging terrain, combined with complex Ecological and Archaeological restrictions, ensured that tight control of all resources was required, along with open and clear communication with all stakeholders. Facilitated by Soil Engineering’s experienced Land Liaison team, stakeholders were kept up to date throughout the works with any changes. Access management was undertaken by dedicated team members, responsible for delivery of all protection packages, and handover of reinstated sites on completion.