An investigation is under way into why a major retaining wall gave way at a Cleveland building site

A PROBE is under way into why a major retaining wall collapsed at a Cleveland building site, damaging sewerage lines and an adjacent property.

CAVE IN: Excavators work to backfill the cave-in at the Cleveland unit building site. Bent and twisted metal sheet piling took the brunt of the impact. Photo: Brian Williams

CAVE IN: Excavators work to backfill the cave-in at the Cleveland unit building site. Bent and twisted metal sheet piling took the brunt of the impact. Photo: Brian Williams

Sheet piling sagged into a major excavation for the eight-level, 59-unit Reflections project at Middle Street near Raby Bay.

It forced the evacuation of 16 residents from an adjacent unit block as fears were held for their safety.

Excavators frantically piled dirt against the retaining wall through Saturday night in a bid to stop any further movement.

CAVE IN: Excavators work to backfill the cave-in at the Cleveland unit building site. Bent and twisted metal sheet piling took the brunt of the impact. Photo: Brian Williams

CAVE IN: Excavators work to backfill the cave-in at the Cleveland unit building site. Bent and twisted metal sheet piling took the brunt of the impact. Photo: Brian Williams

QFES laser monitoring is in place to detect any further slippage. Residents were given emergency accommodation by the state government and about 60 houses at Cleveland, Cleveland Point and Toondah lost gas services.

Peter Endacott, who owns the site with partners, said the area was secure, with contractors having conducted substantial back-filling.

“Thankfully no one was injured,” he said. “(Builder) Kyronn and their subcontractor, Australian Sheet Piling, have vast experience in delivering fully engineered solutions such as the one approved for our site and they have our full confidence.

“We will be working very closely with Kyronn, ASP and their engineers to determine the root cause of this event so that timely rectification can be completed prior to construction recommencing.”

Redland City Council general manager infrastructure and operations Peter Best said there had been a significant movement of earth at the site.

He said it was a wet site, likely due to high water tables but did not know what had caused slippage.

“Metal buckled out and down. It must have been a tremendous force,” he said. “Safety and public health have been paramount for council.”

Queensland Fire and Emergency Services inspector Daryl Rush said soil subsidence had hit utility connections.

“There was also other works undertaken to ensure water supplies were shut off and also some leakage from sewerage that had to be off loaded,” he said.

Builder Kyronn said work continued under the direction of engineers. “We acknowledge the seriousness of the matter and the urgency of ensuring primarily public safety and secondly restoring local utilities,” the company said.