Geotechnical and geophysical methods used for site characterization, as well as instrumentation for geotechnical monitoring, have advanced enormously in recent decades. As a consequence, a deeper understanding of the mechanical and physical properties of natural deposits, including their spatial variability in situ, is now possible. This lectures considers the modern monitoring systems that have allowed the observational method to be applied to a greater range of situations with increasing confidence.
Engineering design consists of a sequence of decisions, which should satisfy the client’s objective performance requirements. This lecture will argue that an assessment of geotechnical performance must involve ground displacements, and that the traditional approach of specifying safety factors is potentially wasteful. In particular, the Limit State Design (LSD) approach adopted in the Eurocodes will be shown to lack objectivity and therefore to be inadequate to the needs of clients and society at large. Improvements will be proposed through the adoption of Mobilizeable Strength Design (MSD) principles in which the designer explicitly considers the stress-strain behavior of the ground.