Thirty five boreholes and twenty three CPTs were required across the extent of the site. The sites included working on the road for bridge pile information, open public areas alongside the stream and in the confirms of industrial operations and a holiday park.
The bore holes were a mixture of cored holes with SPTs at 1.5m and fully core holes and were supplemented by the results from the CPTs.
The material encountered varied from heavy boulder fill at the Hutt River mouth where the the stream exits, to bands of gravels, sands and silts. The team at Griffiths Drilling worked with the clients URS New Zealand Ltd and AC Consulting Group Ltd to ensure the results needed from the difficult conditions were obtained.
Access to the stream was sometimes complicated by the lack of room between the stream edge and the various buildings alongside and the drilling teams had to work around the operations of the various industries and businesses whose areas we were working in.
For safety, with a large number of utility feeders to the industrial area of Seaview, all bore holes were vacuum excavated prior to drilling to ensure any services not identified through plans were picked up.