Screw Pile Installation at a Challenging Site
Pile Vic was engaged to install 193 screw piles to provide foundational support for a new Early Learning Centre in Werribee
While the project initially appeared relatively straightforward, the ground conditions proved to be far more complex than expected. Inconsistent underground obstructions, hard ground and rock at varying depths meant the installation required careful assessment, clear communication and a more involved installation approach.
The Project
The project involved screw pile installation for a new Early Learning Centre development in Werribee.
Pile Vic was required to install 193 screw piles, each with a minimum depth of 2.8 metres. The site was generally flat, but the below-ground conditions created significant challenges once works commenced.
The Site Challenge
The main challenge on site was the presence of inconsistent underground obstructions, often referred to in the industry as “floaters”. These are rocks or hard materials sitting within the soil, rather than forming a consistent rock layer.
The soil report included multiple boreholes, which provided useful information; however, the actual site conditions did not fully align with what was encountered during installation. The report extended to approximately 1.8 metres, while the required screw pile depth was a minimum of 2.8 metres. This left a further metre of unknown ground conditions below the tested depth.
Once installation began, some piles reached “refusal” at inconsistent depths across the site. In piling, refusal means the pile can no longer be advanced because it has hit rock, very hard ground or an obstruction.
On this site, refusal was occurring at varying depths. In some locations, the piles encountered obstruction from around 500mm below the surface, while in other areas they could progress much deeper before reaching hard ground or rock.
Because this was happening inconsistently, the team could not assume they had simply reached a uniform rock layer across the entire site. Further investigation and pre-drilling were required to confirm the ground conditions and allow the piles to be installed correctly.
The Pile Vic Solution
Pile Vic worked through the site methodically, assessing ground conditions as they were encountered and adapting the installation process to suit the conditions.
Where normal screw pile installation would usually involve screwing the pile directly into the ground until the required depth or founding condition is achieved, this site required extensive pre-drilling due to the presence of underground obstructions and hard ground above the founding rock.
The team pre-drilled the pile locations to get through the difficult upper ground conditions, then installed the screw piles down to the required founding layer. This allowed the piles to be installed to the required depth while still working within the constraints of the site.
Two crews were used on the project to support progress and manage the additional work required.
Installation Details
The final installation included:
- 193 screw piles
- Minimum pile depth of 2.8 metres
- Extensive pre-drilling due to inconsistent underground obstructions and hard ground
- Two installation crews
- On-site welding of selected pile caps
- Completion over approximately 10 working days
The project also required on-site welding, as some piles needed a specific type of cap welded to the top. While this is not required on every project, Pile Vic arranged for welding to be completed on site as part of the overall installation process.
Communication and Variation Management
Because the site conditions differed from what was expected, the additional drilling and installation requirements needed to be communicated clearly.
Pile Vic’s approach is to keep builders informed when site conditions create extra time, labour or costs. On projects where conditions do not match the soil report or expected scope, this communication is important to avoid surprises and ensure the builder understands what is required before works continue.
On this project, works were paused while the builder confirmed the additional requirements and estimated costs with the owner. Once everything was confirmed, the Pile Vic team remobilised and completed the installation.
The Outcome
Despite the challenging ground conditions, Pile Vic successfully completed the screw pile installation across the site.
The 193 piles were installed over approximately 10 working days, including the additional pre-drilling and on-site welding requirements.
The project highlights the importance of working with an experienced screw piling contractor who can respond to unexpected ground conditions, communicate clearly with the builder and adapt the installation methodology when the soil report does not fully reflect the conditions on site.
Why This Project Matters
This Early Learning Centre project demonstrates why site experience matters in screw pile installation.
Even with multiple boreholes and a soil report in place, ground conditions can vary significantly across a site. When that happens, the installation team needs to know when to stop, assess, communicate and adapt.
For builders, this project is a reminder that a soil report provides important guidance, but it does not always tell the full story of what will be found below ground. For Pile Vic, it was another example of delivering a practical foundation solution in challenging ground conditions while keeping the project moving toward completion.
Project Snapshot
Project: Early Learning Centre
Location: Werribee, Victoria
Scope: Screw pile installation
Number of piles: 193
Minimum depth: 2.8 metres
Main challenge: Inconsistent underground obstructions, hard ground and varying refusal depths
Solution: Pre-drilling, screw pile installation and on-site cap welding
Outcome: Installation completed over approximately 10 working days