Case study: massive voids

The Suter Pier project at the Port of Townsville, Queensland, Australia.

Located on the coast of North Queensland, Australia, the Port of Townsville is a very important cargo terminal. Suter Pier, the central hub of the Port, had been founded on mixed hardcore fill, retained by a high perimeter seawall.

By 2004 time and tide appeared to have washed out significant volumes of the fines from between the rocks. This had caused extensive voiding and had developed the risk of possible slab failure or collapse due to the very heavy storage loads put on the shed floor. The Construction Manager and Project Engineer for the Port accepted the tender of Grouting Plus Solutions to restore the support base for this enormous (over 5,000 square metre) storage facility.Benefil was the product selected to fill large interconnected voids under the floor slabs adjacent to the seawall.

The Suter Pier project saw Grouting Plus Solutions inject Benefil under approximately 1,000 square metres around the shed perimeter and the work was completed over a period of ten days in mid-2004. 210 cubic metres of Benefil were injected, while the shed remained fully operational with various contents piled high. That included mountains of stock feed.

Beneifil was injected from above and behind the wall at the rear to encapsulate the rocks and fill the voids under the shed floor.

All the time ships were berthing, unloading and loading at the cargo wharves that run along each side of Suter Pier Shed. There was virtually no interruption to the workings of the Port.

For this work Benefil was produced at a relative gravity of 50 kg per cubic metre to suit the high floor-loading requirement. (The density can be varied to suit other tasks: relative gravity of 22 kg/m3 suits the filling of fuel tanks that are to be made safe for abandonment and relative gravity of up to 70 kg/m3 may be produced to support heavier structures). Combining economy, ease of application, lack of disruption and engineering strength, Benefil was the right answer to the demands of this Townsville Port work.