Exeter Trust House

Terra Firma (South) has extensive experience of the geotechnical and geo-environmental investigation of brown field sites to allow developers to comply with the requirements of Local Authority Planning Departments and the Environment Agency.

CASE STUDY: EXETER TRUST HOUSE, EXETER UNIVERSITY

Terra Firma (South) were initially retained as consulting geotechnical engineers for the construction of a new 5-storey student accommodation block in the centre of Exeter, Devon.

The geotechnical site investigation was undertaken using windowless sampling boreholes to determine the geotechnical properties and bearing capacity of the underlying Whipton Formation.

Terra Firma (South) provided an economical foundation solution using piled/vibro foundations, which overcame variable ground conditions and allowed for the high loadings of the building.

However, during the earthworks phase of development three Underground Storage Tanks (UST’s) were identified.

A contamination risk assessment had previously been undertaken by another company who had failed to identify the UST’s on-site. Therefore, Terra Firma (South) following on from our geo-technical work was approached to provide a quick solution to the problem.

The three UST’s were decommissioned and together with the concrete bund removed by a specialist contractor under our supervision.

The immediate surrounding soil was visually inspected and monitored using a Photo Ionisation Detector (PID) to determine the extent of removal. Soil samples were also taken from directly below, downstream and upstream of each removed UST in order to assess any potential risk from poor husbandry, spillages and leakages.

The validation testing revealed that an insignificant risk was present to human health and the aquatic environment from the UST’s located on site. The validation report was hand-delivered to the local authority and approved the next day.

Terra Firma (South) was able to manage unexpected ground conditions and extreme time constraints of this project to deliver.