Engineers Australia

Palmers Road Landslide: Investigation, Analysis & Remediation

Mark Adams

Slope instability is a relatively common occurrence in the Gosford – Lake Macquarie – Newcastle area. The occurrence of landslides and their mechanisms are determined by the geology and hydro-geology of the various regions and care must be taken to understand this regional context when investigating and designing engineering works.
In June 2008 a routine maintenance inspection of the southbound carriageway of the F3 Freeway identified distress in a cutting slope approximately 1km south of the Palmers Road Interchange. The distress was observed in the form of buckling of the concrete pavement slabs in the shoulder of the freeway, over-steepening of the toe of the slope and significant tension cracking over the first bench of this 35m high slope.

The presentation will detail a case study of the detailed investigation, analysis, design and remediation of the landslide. It will also provide some details of the early post-construction monitoring and consider the effectiveness of the remedial works. The case study demonstrates the importance of understanding the local / regional geological and hydro- geological conditions when investigating and designing engineering works. It also highlights the importance of considering how time will impact these conditions.

Given the extent and nature of the works ongoing and planned in the Hunter Region, this case study provides a timely reminder to the profession of one of the key geological / geotechnical challenge of working in this area.

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