Ruddlesden geotechnical


Subsidence Investigation and Assessment

Investigation of the ground conditions beneath existing structures that have experienced foundation subsidence/ settlement is undertaken by Ruddlesden geotechnical.

Following a review of desk studyinformation, this will often include hand- or machine-excavated trial pits, with boreholes and laboratory testing.

Factors considered as possible reasons for movement typically include trees, drains and bearing capacity.

Our report would typically include likely causes for the movement and remedial design recommendations, which might include conventional or piled foundationunderpinning.

Case Study

Subsidence Investigation, Exeter

A void was encountered during construction works beneath an existing residential property in Exeter. It was feared that the void might compromise the integrity of the property, as the existing foundations were no longer being supported. Ruddlesden geotechnical were called out on behalf of a consulting engineer to investigate the ground conditions, to assess possible reasons for movement and to provide appropriate remedial recommendations.

The Phase 1 geotechnical assessmentindicated that this was likely to be due to a damaged rainwater downpipe, which had resulted in the wash-out of loose fines within made ground, associated with the basement of a historical property, present prior to the construction of the Victorian terrace.

A subsequent geotechnical investigation, which comprised hand-held window samples and dynamic probes within the footprint of the existing building, indicated that the made ground was in the region of 3m thick and was present beneath the central and eastern-half of the building.

Ruddlesden recommended that, to guarantee the serviceability and integrity of the existing building, the foundations be underpinned on to the underlying breccia using cantilevered mini-piles or the made ground be consolidated using a low-mobility grout.

  • AGS
  • Constructionline
  • CSCS
  • SMAS
  • ECFC trust