By J.P. Giroud
To: Allan J. Breitenbach
From: J.P. Giroud
Copy to: Ron Bygness
Subject: Comments on article about the history of geomembrane interface strength tests Geosynthetics
I read with great interest your article in the February-March issue of Geosynthetics on the history of geomembrane interface strength tests. Please accept my congratulations.
I take this opportunity to add a few facts, which, I believe, pertain to the history of shear tests with geosynthetics.
In 1973, I wrote a paper on geomembranes (not yet called geomembranes but “rolled sheets”), (Giroud 1973), in the main French technical journal on civil engineering at the time. In this paper, I mentioned tests done using a 100 × 100mm (4 × 4in.) shear box on geomembrane/geotextile and geomembrane/soil interfaces. These tests had been performed in 1971, under my supervision, in the soil mechanics laboratory of the University of Grenoble.
These were, perhaps, the first interface shear tests ever conducted with geomembranes. In those days, I used butyl rubber and PVC geomembranes. The shear tests on the geotextile/geomembrane interface were particularly interesting, because they supported the first use of a geotextile to protect a geomembrane, which took place in 1971.
In 1977-1978, at the University of Grenoble, France, with J.P Gourc we developed a large shear box: 250mm (10in.) wide and 400mm (16in.) long. Descriptions of this shear box, with photos and test results, were published in 1979 and 1980 (Delmas, et al. 1979; Collios, et al. 1980). It is possible that this was the first large shear box specifically developed for testing geosynthetic interfaces. In the 1980 paper, we proposed the terminology “friction efficiency” (tan δ / tan ø ) and “cohesion efficiency” (adhesion/cohesion), a terminology that has been adopted by some authors.
The first HDPE textured geomembrane appeared in 1988 and we immediately performed shear tests with a large shear box, 300 × 300mm (12 × 12in.), at Geosyntec with Rob Swan; and we compared the results of these tests with the results of inclined board tests. The tested interfaces included geomembrane/soil, geomembrane/geotextile, and geomembrane/geonet.
We also performed full-scale tests on the slopes of a landfill being constructed for Waste Management of North America in 1988. This combined laboratory and field effort is summarized in a paper presented at the 4th International Conference on Geosynthetics (Giroud, et al. 1990). To the best of my knowledge, this was the first paper presenting interface shear strength test results on textured geomembranes as well as the first paper presenting full-scale tests to evaluate the stability of geosynthetic liner systems on slopes.
I hope these facts could contribute to your already impressive knowledge on this important subject.
Again, Allan, you should be congratulated for this interesting [series] and Geosynthetics magazine should be commended for publishing it.
Giroud, J.P., 1973, “L’étanchéité des retenues d’eau par feuilles déroulées”, Annales de l’ITBTP, 312, TP 161, Décembre 1973, pp. 94-112 (in French).
Delmas, P., Gourc, J.P., & Giroud, J.P., 1979, “Analyse expérimentale de l’interaction mécanique sol-géotextile–Experimental analysis of soil-geotextile interaction”, Proceedings of the International Conference on Soil Reinforcement, Volume 1, Paris, Mars 1979, pp. 29-34 (in French).
Collios, A., Delmas, P., Gourc, J.P., & Giroud, J.P., 1980, “Experiments on Soil Reinforcement with Geotextiles”, The Use of Geotextiles for Soil Improvement, 80-177, ASCE National Convention, Portland, Oregon, April 17, pp. 53-73.
Giroud, J.P., Swan, R.H., Jr., Richer, P.J., & Spooner, P.R., 1990, “Geosynthetic Landfill Cap: Laboratory and Field Tests, Design and Construction”, Proceedings of the Fourth International Conference on Geotextiles, Geomembranes and Related Products, Vol. 2, The Hague, The Netherlands, May 1990, pp. 493-498.