Wollongong City Excavation & Demolition was contracted Early works package by Bell Corp Corporation at the start of June 2023. We commenced site remediation of the 3 Hectare block in June. This project included more than 6000 tonnes of asbestos contaminated soil. WCED undertook work on 2 encapsulation cells for the asbestos, with a total size of 40 x 20 x 4m deep (3200 m3) as per RAP. All areas were cleared prior to commencing earthworks under the supervision of a Clear-Safe Inspector. Our operators drilled more than 200 piles of 600mm dimensions up to 10 metres deep to socket in the rock base. The piles were connected by a concrete footing at the top to form the base of the footing for the wall, the 290mm core filled block wall was approximately 400 linear metres demonstrating the sheer size of the project. The block wall was up to 5500 high, with 1400m2 of wall holding up all the backfilled material. The structural engineer used a Geogrid (TENSAR 570) from Geofabric products every 600mm coming out from the wall to the backfilled soil to reinforce the soil to avoid any shear or slippage of soil. We cut a quantity of more than 50,000 tonne and fill of over 40,000 tonnes. During our excavations we went 6 meters deep, following all civil engineer specifications. All earthworks were under the supervision of a Level 1 Geotech. For the cut we did the benching to avoid any collapse. The fill layer was 200mm deep and we conducted compaction testing for every 500m2 – passing over with the pad foot 12 tonne roller. Due to the extensive size of this project, we used big machinery like the Cat Dozer D8 to do the cut and 24 tonne excavators to load the dump truck and place it near the fill areas. To decrease the cost over the overall project, we used any topsoil generated from the site in landscaping, capitalising on any material we had onsite.
Summary of Work:
Excavation, Remediation & Civil construction across a 30,000m2 site of hardstand, green waste and contaminated soil.
Remediation and encapsulation of 6000 tonnes of asbestos contaminated soil
More than 200 piles up to 10m socketed into rock.
400 linear metres of 3 – 6m height 290 mm core filled block retaining wall.
Water proofing for retaining wall.
Drainage backfill along the wall .
Compaction using padfoot roller.
Cut of 50,000 tonnes of soil and fill of over 40,000 tonnes of soil using D8 Dozer and 24 Tonne Sumitomo Excavators.