Case study: seawalls

Circular Quay, West Promenade, Sydney.

Circular Quay is at the heart of the Sydney harbour ferry terminal and the original wharf and seawall date back to the 1930’s. Over time, constant ferry wash had eroded large sections of the foot of the inner revetment wall and as a consequence a significant portion of backfill was eroded away. Part of the project was the repair of the foot of the revetment wall via cement grout filled bags to re-instate the base of the revetment wall to prevent future erosion of fines and backfill.

Benefil RG50 was selected as the flowable grout to fill the void space behind the grout bags and the remaining backfill. Benefil was injected via 40mm HDPE pipes under the grout bags into the void space at 3m intervals along a number of bents. The injection process was straight forward with Benefil moving along the void up to 12 metres from selected injection points. The allocated budget for the project was 45m3 and work was completed in 3 days without significant interruption to the terminal or tourist traffic.