Stockton Events Car Park Ground Investigation

Tender description

The Homes & Communities Agency wish to carry out an intrusive ground investigation for a site identified for potential development at the Occasional Events Car Park in Stockton-On-Tees (see Figure 1). The ground investigation will be carried out in two separate stages of work: • Phase 1 – Exploratory Investigation –To investigate the prevailing ground and contamination conditions on the site and identify potential constraints to the proposed development. • Phase 2 – Additional Investigation – To further investigate any particular conditions or constraints that may impact on the proposed development. The scope of works will be dependent on and targeted based on the findings of the Phase 1 Investigation. The Phase 2 scope is therefore indicative only, and will be subject to confirmation following the completion of the Phase 1 works. It is proposed that the Phase 1 Investigation site works will be carried out commencing in early January 2016. The Stage 2 investigation will be carried out following the completion of Phase 1. Based upon current programme, it is envisaged that it will be carried out during Spring 2016. The aims of the investigation are to identify the thickness, nature and variability of made ground and drift deposits, and confirm the depth of bedrock. The investigation will also aim to characterise levels of soil and groundwater contamination and soil gas spatially and vertically across the site. A desk study of previous GI information available for the site has indicated extensive made ground up to 8m thick on the site, underlain by alluvium, localised glacial deposits and Sherwood Sandstone bedrock. The made ground is indicated to be highly variable, with cobbles and boulders of concrete and fused slag frequently reported. Resonance (sonic) drilling is proposed for boreholes to enable such materials to be penetrated and the underlying materials investigated. Due to the depth of investigation required and the nature of made ground materials identified, it is anticipated that a JCB 3CX will be unable to complete the proposed trial pitting works. Previous trial pitting on the site has successfully been completed using a 20T tracked excavator. In order to provide information on the chemical and geotechnical variability of the made ground and alluvial deposits, it will be necessary to recover continuous soil cores from a number of boreholes, with hiqh quality open tube samples obtained elsewhere. A number of boreholes will be extended into rockhead to enable investigation and installation of groundwater sampling instruments in bedrock. Please refer to attached documentation for more information relating to this contract.