JPG were appointed to carry out a desk study, ground investigation and remedial strategy report for this commercial development comprising three warehouses.
A number of geotechnical constraints were identified including opencast mining to 7m depth in the western area of the site and shallow mine workings to the north of the opencast backfill area. Up to 4.8m of made ground and three shallow coal seams were proven during the ground investigation.
JPG recommended the following: gas protection measures in accordance with Characteristic Situation 2 in the natural ground area and Characteristic Situation 3 within the opencast backfill area. No other remediation measures were deemed necessary. Excavation and recompaction of the upper 2m of material within the footprint of Unit 1 followed by ground improvement using vibro-columns or piles. For Unit 2 and 3, a ground bearing slab could be founded on the shallow natural ground. Concrete is to be designed to Design Sulphate Class DS-2 and ACEC Class AC-3z.