Cliff Stability Assessment, Dorset

There was a stability risk at a cliff-top site on the Isle of Portland, as indicated by a Phase 1 Geotechnical Assessment, previously undertaken by Ruddlesden geotechnical.

Ruddlesden geotechnical were commissioned to assess the potential for landslip, ascertain the likely landslip mechanism and causation and determine the relative risk of collapse.

Due to restricted access, rope accesstechniques were utilised to collect rock mass data for use in structural kinematic analyses to ascertain the likely failure modes.

The results of the kinematic analyses (and site observations) indicated the potential for rockfall and wedge-type failures within the top 10m of the cliff-top, confined to one particular geological unit.

Remedial measures, comprising rock-bolting and meshing, were recommended to maintain the existing cliff profile and hence long-term stability of the site.

  • AGS
  • Constructionline
  • CSCS
  • SMAS
  • ECFC trust