Marc is involved in the second stage works at Clyde Mountain. an interesting and challenging site. RMS providing updates via the following website:
Slope Stability 2013 will provide a forum for open pit mining and civil engineering practitioners, consultants, researchers and suppliers worldwide to exchange views on best practice and state-of-the-art slope technologies. Best practice with respect to pit slope investigations, design, implementation and performance monitoring will be discussed during the symposium.
The ACG is delighted to host this symposium in Brisbane for the first time. Past symposia have been held in Vancouver, Canada, 2011; Santiago, Chile, 2009; Perth, Australia, 2007; and Cape Town, South Africa, 2006.
We are attending this Friday
We are currently assisting RMS with slope stabilisation works at Clyde Mountain on the Kings Highway. The area has a long history of landslides driven by a coincidence of road geometry and bedding. Widening works in the late 1950s undercut bedding dipping steeply into the road way leading to the current problems. Failures occurred during widening (1959-about 30,000m3), in 1993 (about 5,000m3) and last year (April 2012-about 1000m3).
More information about the project available through the RMS website.
We have added a new SRA page that will be expanded to include more detail about our SRA, and slope risk management capabilities Marc Hendrickx and Associates are the best choice for independent advice on slope risk management.
Marc Hendrickx presented at the 2012 RMS Geotechnical Conference. The title of Marc’s paper was “Management of small rock falls on the F3 Freeway”.
We’ll post a link to the presentation as soon as RMS put them up on their technical pages.
Here’s the Abstract:
The Sydney-Newcastle Freeway (F3) is a major transport corridor linking Sydney with the Central Coast, Newcastle and Northern NSW. Between Kariong and Wahroonga the freeway passes through spectacular rock cuttings up to 50 m high in Hawkesbury Sandstone. These remarkable engineering structures were constructed by drill and blast methods in the late 1960s. The height, steep design with an absence of benches and narrow carriageway configuration has left an ongoing legacy of regular maintenance and inspection to reduce the risks of rock falls impacting the carriageway.
Qualitative slope risk analysis, using the latest version of RMS Guide to Slope Risk Analysis version 4, rates many of these higher slopes (Slopes >18m height) as high risk (~ARL2) for a direct impact from a small (<0.2m diameter) rock fall. A quantitative risk analysis (QRA) was undertaken as an independent check on the results. The QRA integrated estimates of rock fall frequency based on observations, the results of rock fall modelling software to assess potential rock fall trajectories and their probability of impacting the carriageway for different cut heights and geometries; along with traffic counts and assessed vulnerabilities, as a means of assessing the risk to life. The QRA confirmed the outcome of the Qualitative Risk Analysis. The results were combined with earlier qualitative assessments of the cuttings undertaken under ver 3.1 of the RTA’s Guide to Slope Risk Analysis to provide an overall risk to life.
Current management practises in involve periodic (10-15years) devegetation, scaling and stabilisation of any larger rock fall hazards using passive rock dowels or shotcrete. The costs of this work are high and do little to affect the long term risk of small rock falls which re-emerge overtime as vegetation re-establishes and rocks erode as they are exposed to the weather. Rock fall mesh is installed on a number of cuttings on the F3. A comparative cost analysis was undertaken to assess the cost of installing mesh on high cuttings on the F3 south of the Hawkesbury River. The cost was found to be competitive with current management practises and has the added benefit of maintaining slope risk levels at acceptable levels over time.
13 September 2012.
NSW Roads and Maritime Services confirms Marc Hendrickx and Associates Pty Ltd was successful in its application for the following Professional Services Panels:
Slope Risk Assessment
Investigation and design of Slope Remediation and Treatments
Supervision of Slope Stability Works