Temporary Excavation Stabilisation – Platipus® Civil Anchors

As property values continue to climb in prime locations such as Mt Maunganui, innovative solutions are required to develop and enhance properties within existing boundaries. This property owner wanted to create a basement underneath the front half of their existing home, and this required excavating underneath the house and erecting temporary structural support. However, the excavation would create a steep batter at the back of the proposed basement which would require adequate support prior to construction of the permanent block retaining wall.

Design

To temporarily stabilise the batter and allow the permanent block retaining wall in front to be constructed safely, the project engineer utilised the Platipus S6 Earth Anchor system with DuraForce AS280 Geotextile, steel mesh and 4×2 timber battens and a 100x100x5mm load plate on the surface. The anchors were to be installed at 1m horizontal spacings and 900mm vertical spacings in an offset ‘grid’ pattern. The top row of anchors were to be at a load-locked depth of 3m with a test load of 17kN and the bottom two rows at 2m load-locked depth with a test load of 9kN.

Installation

At the commencement of the works, Cirtex visited the site with the contractor to provide installation training, explain the various components and assist with methodologies. The S6 Anchors were installed using an 11kg hydraulic hammer/power pack and tested to the design loads using specialist testing equipment hired from Cirtex. 38 x S6 Anchors in total were successfully installed, achieved the design loads required over the course of approximately 4 days.

The products used provided the following benefits to the project:

• Protection of a high value home during renovations
• Provided a safe working environment for crews during construction of a permanent retaining wall
• Technical support from Cirtex both onsite and via phone/email during installation
• A readily available solution that could be supplied to site
• Installation was possible using lightweight equipment