Harvest Estate – MagnumStone™ Wall

Harvest Estate, located in Australia’s iconic coastal destination of Byron Bay, is a brand new master planned sustainable community with around 145 new houses being built in this stage. Set on 150 acres just over 2km from the beach, Harvest Estate features over 50,000m2 of recreational open space, including bike paths, walking tracks and its very own community centre and gardens.

To help create flat, usable land, Harvest Estate required an aesthetically pleasing retaining wall system that was quick and easy to construct, but also allowed construction in an area with a high water table and underlying loose-sand soil conditions. With seven walls required in total, each supported a mixture of roads and residential sections, some with noise barriers running along the top.

DESIGN

Retained to a maximum height of 2.4m, the immediate proximity of swale drains and creeks meant there were significant toe slopes to be considered for most structures. CCA Winslow were able to build the seven walls with a combination of gravity and MSE designs without changing the overall look. The main section of each wall was designed as a gravity wall with extenders, but in the lower layers of each wall, an MSE design using StrataGrid geogrid strips was also used to overcome global stability challenges.

INSTALLATION

Cirtex worked closely with CCA Winslow to provide training and support throughout the installation process. Once the level pad was created, CAA Winslow found the blocks and StrataGrid easy to place, with the extenders of the upper layer resting on the compacted engineered fill. Drainage aggregate was placed within MagnumStone’s hollow core, with DuraForce geotextile separating the back of the blocks from the fill layers beneath the built up road to prevent any soil migration. The MagnumStone walls were also built over drainage culverts with bridging slabs to prevent loads on the culverts. With the retaining walls in place, Harvest Estate are now opening up limited sections for sale, offering residents the ultimate beach lifestyle in the heart of Byron Bay.

The MagnumStone system provided the following benefits to the project:

• Can be designed using MSE and gravity design without changing the aesthetics
• Quick and easy to install
• Able to be used in soft sand soil condition with a high water table
• Able to incorporate a noise wall into the top of the wall.