Speakers

We shall delve into a range of topics on the liquefaction of sands.  The importance of the depositional environment was known to early water-supply USA dam builders in the first half of the 20^th century. This is a lesson still being re-learned in tailings, and is perhaps an example of Morgenstern’s recent use of the term “embedded ignorance”. Crucial to this for many tailings types is the shoreline location as the pond is raised during upstream construction.  The question of fabric or structure on the likely insitu steady state is noted, not only on a microscopic scale but also on for example underwater beach angles. The usefulness of considering shear stress densification, under controlled conditions, is presented with several examples. Thoughts on the inappropriateness of isotropic consolidation and Ko consolidation, if by that we mean a no-lateral-strain condition, are posed. Horizontal stresses will be discussed following on a recent re-quote of Jamiolkowski’s conclusion that horizontal stress measurements are the black hole of geotechnical engineering.

While the sensitivity of CPT interpretation should be well known to most, reflection on the variation of ratio of H:V stresses throughout a sand structure arguably requires consideration. Comments on the collapse surface will be made, especially vis-à-vis commentary that it is not an intrinsic property. A review of source and magnitude of uncertainties in defining parameters for design is overviewed. While brittleness has now belatedly reached most everyone’s cognitive awareness, question still need to be addressed in application of the especially in mechanisms for the typical retrogressive nature of most if not all flow failures.