Almost 10 years ago, at an Australian Geomechanics Society meeting, I lamented how bad some Tasmanian “expert practitioners” were at doing soil testing and classification for houses. Mostly, like bad doctors, their work goes unchallenged – until something goes wrong.
Recently, when providing a second opinion about a house site to a client, I was reminded that people are still receiving bad geotechnical advice. The property in question was not in a declared landslide zone, but nearby, serious slope instability issues were reported on 15 years ago by Mineral Resources Tasmania, and house-threatening landslides are still occurring in the area. This situation ought to have been recognised by the classifier, but not only did his advice fail to refer to potential instability, it recommended on-site wastewater discharge on steep, hummocky, probably unstable ground immediately adjacent to mapped “old landslides”. Not a good idea.
How do you know when you have received bad or inadequate geotechnical advice? My thoughts on soil tests for house sites (PDF download) might help.