The Terzaghi Lecture is the highest award bestowed by the ASCE Geo-Institute and is presented at GeoCongress, the Geo-Institute annual conference. After leaving Vienna, Terzaghi was a faculty member at Harvard University from 1938 until his retirement in 1953. Giroud delivered the Terzaghi Lecture on March 11, 2008, at the GeoCongress in New Orleans, Louisiana (the video of the original presentation is here). In the following four years, he delivered updated versions of his Terzaghi Lecture in North America (Salt Lake City, Pittsburgh, and Lawrence, Kansas in 2009, Kingston, Canada in 2008 as Golder Distinguished Lecture, and Montreal in 2009), Europe (London and Paris in 2009) and Australia (Brisbane, Sydney, Melbourne and Perth in 2012). Two updated renditions require separate mention. On November 13, 2009, Giroud presented the updated version of the 2008 Terzaghi Lecture at Texas A & M University, on the occasion of the 17th Spencer J. Buchanan Lecture (the video with all the presentations of the event is here). A paper closely based upon the “Terzaghi Lecture” was presented as a “Prestigious Lecture” at the 9th International Conference on Geosynthetics in May 2010 in Guarujá, Brazil.

Abstract

This lecture is based on more than 30 years of work on geotextile and granular filters by the author. A rational approach to the development of filter criteria is presented in a lively manner using animated slides. In particular, the author demonstrates that, while two criteria are needed for granular filters, four criteria are needed for geotextile filters. The author also demonstrates that, while the traditional permeability criterion for granular filters is adequate, the retention criterion for granular filters could and should be improved by adapting some of the features of the retention criterion for geotextile filters. The application of the filter criteria is illustrated and discussed step by step using the case history of the design, construction and performance monitoring of a geotextile filter in a dam constructed in 1970 and still in service as of 2024.