Dynamic replacement -liquefaction mitigation for Hamilton section of Waikato Expressway

This paper describes the design and construction of dynamic replacement columns (DR) to mitigate potential liquefaction of a road embankment in the Hamilton section of the Waikato Expressway in New Zealand. Liquefiable, loose silty sands extend to depths of 6 m to 7.5 m, with some localized deeper layer in the Mangaharakeke gully which is the most challenging geotechnical area of the project. To derive a Value for Money solution, the ground improvement design was carried out using a resilience in design approach, based on a tolerable embankment deformation of 250 mm under the design earthquake event. The design includes stabilization and support of 14m batter slopes, fill embankments on loose ground which is subject to high potential liquefaction. Following clearing of vegetation, a historic landslide area was discovered in the natural slope above the embankment and a Safety in Design approach was implemented to appropriately address this specific issue. During construction, the DR columns were found to refuse in a medium dense sand layer which was underlain by further liquefiable layers. Remedial works had to be carried out using geotextiles and toe berms. Nevertheless, the overall outcome is still cost-effective and achieved the desirable objective of a value for money, resilient solution. The key design methodology of the DR ground improvement, construction issues and remedial works are described in this paper.


  • English

Media Info

  • Pagination: 1105-10
  • Monograph Title: Proceedings of the 13th Australia New Zealand Conference on Geomechanics Perth, Western Australia, 1-3 April, 2019

Subject/Index Terms

Filing Info

  • Accession Number: 01714804
  • Record Type: Publication
  • Source Agency: ARRB Group Limited
  • ISBN: 9780994626103
  • Files: ITRD, ATRI
  • Created Date: Aug 26 2019 11:51AM