Following a series of investigations, we were instructed by the client to compile a detailed Earthwork Specification coupled with on site supervision to enable and validate a large earthwork scheme for a new secondary school in the Vale of Glamorgan. Works are ongoing and progressing well, with inter-communication in the team allowing progression and where necessary revision to the scheme.
Prior to earthworks specification, the development commenced with a series of assessments, comprising a desk study followed by an intrusive investigation comprising trial pits and rotary boreholes. Supplementary investigation works included detailed infiltration testing to determine if sustainable drainage could be considered and specialist geotechnical testing to allow compilation of an earthwork specification as the site is underlain by shallow bedrock comprising the Jurassic Porthkerry Formation, a sensitive rock type that can be prone to high moisture contents and pyritic heave.
Earthworks are used as an effective way to prepare, otherwise unsuitable sites, through flattening or alteration of site levels and improvement of ground strength. This particular site required a complex cut and fill works alongside the existing school which was to remain in operation until the new school is constructed.
The earthwork specification was compiled to allow the re-use of site won bedrock materials, separated into coarse and fine fractions and provided a detailed compaction methodology, including allowable thickness of placed layers, number of passes required by compaction plant and validation testing, before, during and after placement.
The specification was compiled in general accordance with good practice guidance such as BS6031 – Code of Practice for Earthworks and Series 600 of the Specification for Highway Works. The use of site won arisings has also enabled a cut/fill balance within the development, with little arisings to be transported off site and imports restricted to coarse aggregates required for starter layers and sub-slab pavements.
The findings of the phased investigation works prior to development and compilation of a dynamic earthwork specification have enabled a robust earthworks strategy, upon completion allows construction of the next generation of schools for the Local Authority, whilst allowing use of the existing aging school and minimisation of on and off site movements of materials. Get in touch if we can help on your next project.