Former St George’s Hospital Site 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 Former St Georges Hospital site in Morpeth. The ground investigation will be carried out in three separate phases: • Phase 1 – Preliminary Investigation –To investigate areas of previous contaminative land uses in the south of the site and inform a contamination risk assessment. • Phase 2– Detailed Investigation for Access Road – To confirm ground conditions on the alignment of the proposed access road and establish parameters for pavement and earthworks design. To investigate mine workings beneath the road alignments. • Phase 3 – Exploratory Investigation for Development – To investigate the prevailing ground conditions and establish the levels of potential contamination across the wider site area. To investigate potential mine workings on the site and inform a mining risk assessment. To characterise levels of groundwater contamination and soil gas spatially and vertically across the site. In addition to the above, the investigation is intended to identify the thickness, nature and variability of any made ground and drift deposits, and confirm the depth of bedrock across the site It is proposed that the Phase 1 and Phase 2 Investigation site works will be carried out concurrently commencing in mid March 2016. The Phase 3 investigation will be carried out following the completion of Phases 1 and 2. Based upon current programme, it is envisaged that it will be carried out during Summer 2016. A desk study of published BGS information available for the site the indicates the site to be underlain by Glacial Till, with localised sands and gravels in the south of the site overlying Lower Coal Measures bedrock. A drift thickness ranging between 10 and 15m is indicated across the majority of the site. For the purposes of tender, the scope of works shall comprise: • 2 No. Cable percussive holes to depths between 10m and 15mbgl. • 10 No. Cable Percussive Holes followed by open hole rotary to depths between 30mbg and 35mbgl. • 11 No. Open hole rotary to depths between 30mbgl and 40mbgl. • 52 No. Machine excavated trial pits to depths of up to 4.5mbgl • In situ standard penetration testing in selected boreholes • Geotechnical laboratory testing • Chemical laboratory testing • Installation of 50mm groundwater or combined gas/groundwater standpipes • Post siteworks groundwater level and ground gas monitoring and sampling • Provision of factual reports and digital data