The project was to construct 2 large retaining walls in front of the existing failing retaining walls on a tricky and steep site at Whangarei Heads with limited access & hard drilling.
The retaining walls were approximately 35m long each and varied in height from 1.4m to 2.6m. The client had been trying to sell the property for a while but the failing retaining walls were making it hard to sell. The upgraded retaining walls & concrete driveway have immensely increased the value of the property & will make it more attractive to prospective buyers.
Before the construction of the retaining walls, there was major excavation required. This had to be done in stages as to not undermine the house or the driveway.
The retaining walls required drilling to a depth of 5.0m. The ground conditions were very hard & we had to drill through rock to get the poles to the required depth. This made the job very challenging as we had to have larger machinery (a minimum of 12T Excavator) on site to drill the holes but with limited site access, the larger machinery was difficult to manage.
The most innovative part of the project was the way we staged the works on such a tight site to ensure that the existing wall was demolished in stages and the new wall constructed prior to moving onto the next stage. Even materials had to be drip fed to site as there was no laydown area and space was a premium.