Hi All – SSAM (https://app.ssam.net.au/) is the product of my thesis at UNSW and ACARP..

Essentially, with your assistance of industry case studies, I have developed a new empirical slope stability assessment methodology (SSAM) for assessing the likelihood and consequence of excavated slope failure.

With 10 questions, you can calculate your slope’s likelihood of failure (LOF) based on the past performance of slopes with similar geotechnical and geometrical conditions. A 60% likelihood of failure indicates that 6 out of 10 slopes with similar conditions has failed in the past. An equivalent FOS can also be calculated for those more comfortable with this terminology. A FOS of 1 equates to a 50% LOF.

A consequence of failure can be estimated using a new Impact Ratio (IR) which compares the ratio of slope height to stand off distance and predicted failed material runout distance. The higher the IR the higher consequence of failure.

The LOF and IR can then be graphed on a new risk matrix allowing you to directly compare quantitative risk ratings calculated for: (i) the same slope over time, or (ii) different slope designs. The new risk matrix is presented below.

The methodology has been built into an online program accessed from any computer, tablet or smartphone athttps://app.ssam.net.au/

A runout calculator has also been built into the software to provide indicative stand off distances for varying slope heights and failure mechanisms. Estimates are provided for both the stand-off distance perpendicular to the toe of the slope and lateral to the slope face. An example of the outputs for a 38 m high slope are shown below.

Other notes:

  • The software is free to use – just log in using the Trial Version. The Trial Version is fully functional but does not allow users to save data. To save surveys online, please contact me for a username and password
  • The methodology has been validated against the results of 3D LE modelling
  • More information about the development of SSAM and the validation process can be accessed in the Help > About Methodology and Help > Run Out Prediction Charts section of the online tool
  • SSAM is design to used in conjunction with existing slope stability assessment tools

It would be great to see this tool applied in industry where it provides geotechnical engineers and operations a new method to: (i)assess the risk of slope failure, and (ii) record pit inspections in a central database.

Kudos to all who contributed case studies to this research project: Anglo American (Gift Makusha, Thomas Hahn), Peabody (Gavin Lowing, Tim Cartledge), BHP (Dan Payne, Adrienna Robotham, Walter Keilich, Jayson Summerville, Kathryn Young, Leigh Bergin, Kimberly Peckett), Thiess (Steve Gale, Leonie Bradfield), Downer Mining (Dave Edwards), Rio Tinto, Coal & Allied and New Hope Coal (Jim Thornton). Your contribution is much appreciated and I hope you will benefit from the outputs of this research project.

Best Regards,

Ali McQuillan.