RIVERVIEW MINING SUBSIDENCE
Westphalen Drive, Riverview. A previous mine subsidence report identified the presence of historical mining activity beneath the site and the potential for sinkholes to occur.
Due to recent rapid urban growth in Queensland and to meet the land demand, development in subsidence prone areas is an attractive option for developers due to the lands relatively low cost. From previous work conducted at the site, it was concluded that from the results of the sonar, the sizes of the workings appear reasonably consistent with the mine workings plans and that designing for a 6m diameter void over a single bord or a 10m diameter void over a bord intersection appeared to be a reasonable approach.
"Flexible bridging platforms consisting of high strength geosynthetic reinforcement are a cost-effective, viable option. The premise of this approach is not to prevent any surface deformation occurring but to maintain the serviceability of the surface until remediation measures can be undertaken."
A double-layer system design was selected, one that utilised Maccaferri’s high-performance Paralink® 1000 kN geogrid in longitudinal and transversal layers. Custom roll sizes were manufactured to minimise wastage and assist with placement. Maccaferri ParaLink® geogrids are unique planar structures consisting of a monoaxial array of composite geosynthetics strips. Every single longitudinal strip has a core of high tenacity polyester yarns tendons encased in a polyethylene sheath; the single
strips are connected by non-resisting cross laid polyethylene strip that gives a grid-like shape to the composite.