Flexible Solutions in Flexible Ground, Te Ngaere Bay Slip Repair

On Thursday 5th June 2003 a large crack appeared in Wainui Road above Te Ngaere Bay, part of the million dollar view tourist route in the Far North of New Zealand. The crack was initially sealed but continued to open up and by the 10th of June the road had subsided to the extent there was difficulty in traffic traversing the area. GHD was asked to urgently respond and report on the risk to road users and to properties below the road. The immediate risk was assessed and urgent safety measures arranged to avoid the road being completely cut.

Site investigations were implemented and a report outlining the causes of the failure, the ongoing risk, recommended remedial measures and estimated costs of repairs was prepared within two days. The recommended repair was a reinforced earth wall and deep subsurface drainage. Design and contract documentation was prepared and issued to selected tenderers and awarded 10 days after the initial crack had appeared in the road. Due to the rapid response and limited investigations undertaken, a flexible solution was chosen to allow modification and fine tuning of the desig n during construction resulting in an innovative and efficient solution.