Foundations Options Appraisal, Somerset
The Somerset Levels typically comprise a thick sequence of Quaternary and Recent Alluvium/ Tidal Flat Deposits, made up of layers of peat, clay, silt, sand and gravel, underlain by Triassic and Jurassic bedrock deposits.
The cost-effective development of residential housing can be difficult in this area of the country, due to the deep Alluvium/ Tidal Flat Deposits, often ranging between 10m and >20m in thickness, which sometimes results in piled foundations being the default foundation solution, which can often affect the viability of the project.
The upper 1.5m-2.0m of the Alluvium/ Tidal Flat Deposits often comprise desiccated clay soils and can, in some circumstances, provide a suitable founding stratum for shallow foundations.
Conversely, for larger developments, ground improvement can also be considered to facilitate the use of shallow foundations, as a cost-effective alternative to piles.
As part of a general ground investigation, Ruddlesden geotechnical have recently undertaken a foundation options appraisal in Weston-super-Mare for a proposed residential development, where all of the above were considered, to provide the most cost-effective solution for the developer. A mix of piled and strip/ trench-fill foundations were recommended, directly relating to the underlying geology.