Improved definition and physical evidence is needed of the processes and mechanisms involved as soil progresses to liquefaction and residual strength in order to allow refined analyses for dam safety and soil embankment systems and more cost-effective and safe remediation design and analysis. Significant progress is being made in the development of numerical methods for analyses of liquefaction and the consequences. However, the engineering profession will most likely always use empirical correlations of in-situ measurements vs potential liquefaction, pore water pressure generation and earthquake response. Every time a site is evaluated for a seismic design and a soil embankment system remediated, in-situ measurements will be made. This would also provide the fundamentals and basis for development of new methodology and analyses.
New methodologies have to be based on correct mechanisms and processes.
Current specific needs for more complete earthquake engineering analyses can be identified from examination of the last two decades of experience in seismic evaluation of soil embankment systems and the serious limitations that arise when remediation design is attempted. Due to the lack of knowledge and experience involving the behavior of liquefiable soils under field conditions, we are forced to make, for the critical safety of soil embankment systems, simplifying assumptions concerning behavior. We will continue to gather better and better information from real earthquakes over the next decades. This can be started presently and achieved by reseach with model experiments and dynamic shaking on both shake-tables and, primarily, centrifuges. Let me first address the research needs in remediation and retrofitting and then offer a few suggestions of how to initiate a networked research effort.