An article by the NZ Herald reports that recommendations for slope monitoring and early warning made by a geotechnical consulting firm in a report 2 years before the initial failure were not adopted by Auckland Transport. The Birkenhead landslide initially took out 25 parking spaces in a retail area in October of 2017, and a larger landslide in November of the same year took out a micropile or other drill rig working to stabilize the site. Local officials defended the decision, indicating that they instead opted for regular site visits and visual observation of cracks noted in the report. The initial recommendations by GHD Engineers included the monitoring as a minimum, and also recommended several stabilization options in the range of $500k. The current estimates to repair the landslide are $14M to $24M.
Last week was the annual American Council of Engineering Companies of Arizona Roads and Streets Conference in my home town of Tucson, Arizona. Its a transportation themed conference as you might guess, but there are usually a few geotechnical-type presentations. This year, there was an excellent presentation on the SR 87 Landslide that occurred about 1-year ago on the highway between Phoenix and Payson. The presentation was given by Keith Dhalen, PE with AECOM , Wayne Harrison, RG also with AECOM and Scott Neely, PE with Terracon . Read on for my recap of the presentation. (Photo by ADOT via AZGS)
A report has been released by the NYSDOT on the Scoby Hill Landslide which has impacted a 4.2-mi improvement project of Route 219. The report, dated May 20, 2008 was headed to an FHWA peer review panel.
The Feds were call in to help because of the unusual nature of the landslide. The slip surface is very deep, approximately 30-m (100-ft) below the surface and below all of the design phase investigations. And the remolded shear strength of the silty clay forming the slip surface was only 12-14 degrees.
Read on for more details of the slide. (Photo by NYSDOT)