Cliff Stabilisation - Gibraltar

Stabilisation works were required to a 30m high sea cliff following the construction of new properties above.

Access to the crest was severely restricted and the only option was to use rope access techniques. The undercut rock face required a combination of stabilisation methods to ensure it’s long term integrity including:

  • Rock bolting of isolated blocks
  • Installation of restraint cabling to isolated blocks
  • Installation of Geobrugg Tecco mesh support to face
  • Installation of Geobrugg Spider mesh support to overhangs
  • Installation of rock dowels
  • Construction of sprayed concrete scour protection wall at base of cliff
  • Sprayed concrete erosion protection to weak areas of face

Rock bolts ranged from 3m to 9m in length and installed into holes of 45-100mm diameter using both fibreglass and high tensile steel anchors. All anchors were cement grouted. Drilling techniques included the use of hand held rock drills, a drifter mounted on a mast and a DTH system for the larger diameter anchors.

All works were completed to the engineer’s satisfaction, contract duration was 4 months.

Posted in    on 1 July 2008