Champion Lakes Residential Development – Bulk Earthworks

February 2022

DM Civil is often constructing jobs in site conditions that are other than what we expected and Champion Lakes has been no different. However, thanks to our forward-thinking Project Manager Glenn H., we have been able to minimise the impact and provide an innovative cost-effective solution for our valued client DevelopmentWA.

The form of clay encountered on site was unexpected and once the extent was determined (up to 2m thick in some areas), it became evident to DM Civil that there was going to be an issue with re-using this material, making for a significant shortfall in material suitable for surface fill and required A-class site classification.

Our photos paint a solid picture, but also provide context to the extent of the issue, when the original construction of the lake and international rowing course occurred, the clay was pushed out, stockpiled, and then layered over the sand, including clay stockpiles from earlier stages of the residential development. This meant our current stage had received all the unsuitable material from the past developments, making for much more difficult ground conditions to work in. As an experienced earthworks manager, Glenn was faced with a significant challenge in the logistics of material handling and disposal options. Several scenarios were considered, including removal and replacement with expensive clean fill, stockpiling and screening and borrowing sand from depth and thirdly, burying all of the clay material at depth and using the sand won from that depth to become the surface layer. After survey calculations by the DM Civil team, Glenn’s suggestion to the client proved to not only provide a sustainable solution to reuse all the material on site, but to also realise a significant cost saving to the client. With all clay material buried 1.8m or further below finished surface level and the sand below transferred to the surface, an exercise in cost saving, recycling and sustainable construction was provided for the development.

In collaboration with JDSi Engineers’ design team, our survey department was involved first. Using our machines, we test pitted to plot a clay cap survey model to determine the volumes of clay required to be buried. This was then used to calculate borrow pit areas and a total excavation model which was programmed into our GPS controlled machines to allow for more efficient construction on site. The site team, led by Craig V., used the established borrow pit areas to stage the earthworks to minimise double handling of material. Maximising cut to fill operations, DM Civil has been able to complete the burial and site remediation works as forecast and well within anticipated costs.

As a result of the innovation and leadership demonstrated during this bulk earthworks phase of the project, we are now moving ahead on underground installation with an anticipated finish within the 3rd Quarter of 2022 in line with our works programme. This challenge and the very favourable result highlights the value of good project management, engineering and site supervision that DM Civil delivers to our clients. We also acknowledge the value of the collaborative team that has been formed on this project with JDSi Engineers and DevelopmentWA. When we work together, we succeed, and Glenn, Craig along with Sam E., our site engineer, have been recognised by the client and the Superintendent as key to this success – Well done Glenn, Sam and Craig.