Geotechnical Considerations for Basement Construction for Proposed Hospital

For a proposed basement car park at a hospital in Dorset, Ruddlesden geotechnical were commissioned to undertake a geotechnical investigation.

The geotechnical investigation indicated that a thick succession of river gravels was present beneath the site, for the base of the proposed basement.

Widespread collapse of strata was observed in machine-excavated trial pits during the investigation and elevated groundwater pressures were recorded during subsequent groundwater monitoring.

In light of the ground conditions encountered, it was recommended that a top-down construction approach be undertaken, e.g. using a secant bored pile wall, to mitigate the effects of collapsible ground and the need to dewater excavations.

It was also considered that, depending on the weight of the proposed structure, tensioned piles might be required to resist flotation of the structure as a result of the high groundwater pressures.

  • AGS
  • Constructionline
  • CSCS
  • SMAS
  • ECFC trust