Gabion Wall Stability

Murray Riverbank

In the mid 2000’s, instability developed in gabion retaining walls supporting the riverbank in front of an historic homestead on the Murray River downstream of the Wentworth Loch. Advice was sought from a large geotechnical engineering firm which concluded that a major slope failure was imminent and remediation works in excess of $1 million was required to stabilise the riverbank.

In late 2011, SCE were engaged by State Water to inspect the area and review the previous advice and establish the feasibility of more economical stabilisation works. During the investigation by SCE it was established that the riverbank slope failures were associated with soil piping within the alluvial soils and as such, the conventional slope stability investigation undertaken by others was invalid.

SCE also concluded that the main cause of the embankment instability was wash from watercraft using the Murray River and as a consequence recommended the construction of a rockfill embankment with the toe protected by anchored timber pile wall constructed from the water. This remedial method had a total cost of approximately $200,000, 20% of the original method proposed by others.