This meeting may be of interest to those who can make it to London
tomorrow:-
IGS/BGA JOINT MEETING ON WEDNESDAY 30th OCTOBER 2002
At The Institution Of Civil Engineers
1 Great George Street, Westminster, London
5.00pm - 5.30pm
2nd IGS UK CHAPTER INVITATIONAL LECTURE
'Stability Assessment of Ten Large Landfill Failures'
Presented by Professor Robert M Koerner
The Committee of the International Geosynthetic Society, UK Chapter are
pleased to announce that Professor Robert Koerner has accepted our
invitation to be the 2nd presenter of our annual invitational lecture.
Professor Koerner is Professor of Civil Engineering and Director of
Geosynthetic Research Institute, Drexel University, Philadelphia, PA US.
Professor Koerner's interest in geosynthetics spans twenty years of
teaching, research, writing and consulting. He holds his PhD in
Geotechnical Engineering from Duke University. He is a registered
Professional Engineer in Pennsylvania, an Honorary Member of ASCE and a
member of the National Academy of Engineering. Professor Koerner is the
co-author of the first book on geotextiles and has authored and co-authored
500 papers (of which 300 are on geosynthetics) in major engineering journals
and at National and International Conferences. His latest efforts are the
fourth edition of the textbook entitled "Designing with Geosynthetics" and a
brand new textbook entitled "Geotechnical Aspects of Landfill Design and
Construction".
A synopsis of Professor Koerner's presentation is as follows:-
The analyses of ten large solid waste landfill failures. Five are unlined
or soil lined, and five are lined with one or more geosynthetic materials.
The case histories are analysed by a 3-D computer code adjusting variables
(mainly interface shear strength) to arrive at a FS = 1.0. A triggering
mechanism, unique to each site, is then removed resulting in a FS > 1.0.
The same variables and triggering mechanisms are then used in a 2-D computer
code with FS-values decreasing by different amounts. The ratio of 3-D to
2-D factors-of-safety is called a wedge factor and is calculated
accordingly.
Conclusions reached are as follows:
1. Interface shear strengths are the overriding considerations
in varying FS-values. Accurate determination cannot be overemphasized.
2. The triggering mechanisms were all liquid related i.e.,
leachate buildup within the waste mass, wet clay beneath the geomembrane, or
excessively wet foundation soil.
3. The average wedge factor of all case histories without, then
with, the triggering mechanism is a relatively high value of 1.24.
