Excerpts

1984: An excerpt on material properties vs design that closes a paper arguing that whereas impermeability of landfill and canal liners is a guiding ideal that cannot be reached, nearly zero leakage is achievable.

The combination of adequate design and proper selection of materials is the only way to ensure impermeability. In fact, everyday life teaches us not to rely solely on material properties. Flying is a convenient way to travel. If we relied only on material properties to fly, we would be inclined to use balloons because their flying capability is based essentially on material property, (that is, their density is less than that of air). The fact is, however, that we use airplanes which fly primarily as a result of design. Of course, material selection is important in airplane construction. The materials used should have appropriate mechanical properties and be as light as possible, just as geomembranes should have appropriate mechanical properties and be as impermeable as possible.

It is tempting to pursue the comparison between geomembranes and airplanes. The remarkable reliability of the airline industry results essentially from the amount of care involved in the detailed design of airplanes, and the quality control of construction, maintenance and operation of airplanes. The liner industry faces today a challenge similar to the challenge faced years ago by the airline industry when it was plagued by an unacceptable number of accidents.

Adequate conceptual design, proper selection of materials, careful detailed design and quality control during construction, maintenance and operation of geomembrane-lined facilities: these are the necessary steps towards impermeability.

In: Giroud, J.P., 1984, Impermeability: The Myth and a Rational Approach, Proceedings of the International Conference on Geomembranes, Vol. 1, Denver, CO, USA, June 1984, pp. 157-162. [link]

1986: An excerpt on parallels between geotechnical engineering and textiles

One primary mechanism by which geotextiles are influencing the field of geotechnical engineering is the introduction of geotechnical engineers to textile specialists. Using earth as a construction material (geotechnical engineering) and weaving cloth to make garments (the textile industry) are among the oldest professions on earth, and it is surprising that they ignored each other until the middle of the 20th century. This attitude is all the more surprising when we realize the extent to which geotechnical engineering and textiles are part of our everyday universe: many large features of our landscapes (road embankments, retaining structures, landfills, canals, dams and reservoirs) result from geotechnical engineering; each country on earth has selected a piece of fabric as a national symbol; when we see a human being we usually see more textile than flesh; the fabrics they wear are the most convenient way to distinguish between a soldier and a civilian, a clergyman and a layman, and, sometimes, a man and a woman; and when Magritte wants to represent death, he does not show the soul being separated from the body, but the body being separated from the clothes.

In: Giroud, J.P., 1986, “From Geotextiles to Geosynthetics: A Revolution in Geotechnical Engineering”, Proceedings of the Third International Conference on Geotextiles, Vol. 1, Vienna, Austria, April 1986, pp. 1-18. [link]

2000: An excerpt on the reasons for the success of geosynthetics

Clearly, the success of geosynthetics is explained by three fundamental reasons: (i) there is a need for two-dimensional materials in geotechnical engineering; (ii) geosynthetics are the only available materials that meet the requirements for two-dimensional materials in geotechnical engineering; and (iii) many geosynthetics are two-dimensional materials made with one-dimensional elements, which is a very efficient use of matter.

In conclusion, when used as reinforcement, drainage or liners, geosynthetics are, respectively, the muscles, the veins and the skin of the Earth. Never before have construction materials displayed such versatility and performed such fundamental functions. Geosynthetics are therefore here to stay.

In: Giroud, J.P., 2000, “Lessons Learned from Failures and Successes Associated with Geosynthetics”, Keynote Lecture, Proceedings of Eurogeo 2, the Second European Conference on Geosynthetics, Bologna, Italy, October 2000, Vol. 1, pp. 77-118. [link]: Bologna 2000, p. 116

An international society should have an international language. At the IGS, we have agreed to speak English although more than one half of our members do not have English as their mother tongue. In exchange, all members of the geotextile community must agree to use the SI system of units. It is unacceptable, in a modern discipline, that one third of our members still measure geotextiles with their feet.

In: Giroud, J.P., 1986, “Inaugural Address of the First Elected President of the IGS”, Proceedings of the Third International Conference on Geotextiles, Vol. 5, Vienna, Austria, April 1986, p. 1523.

A discipline is mature when it can openly discuss its failures. Bologna 2000, p. 116  

It is hard to believe that a mode of failure that never happened in the past could happen, even if this mode of failure is predicted using a rational analysis. Indeed, geotechnical engineers are accustomed to learn from precedents, which is consistent with what common sense would dictate. However, it should be noted that, while such an attitude may be justified in a relatively old discipline such as geotechnical engineering, it is not appropriate in a relatively new discipline such as geosynthetic engineering. Bologna 2000, p. 107  

A design engineer who often goes to the field is better prepared for design than a design engineer otherwise equally qualified who never goes to the field. A design engineer who has seen a failure is better prepared for design than a design engineer otherwise equally qualified who has never seen a failure. A design engineer who has seen a failure and has written a report about the failure is better prepared for design than a design engineer otherwise equally qualified who has seen a failure, but has not written a report about it.  Bologna 2000, p. 110  

Every time the author has to go to the field to see a failure, he reads what is available on the project and, before going to the site, develops a scenario, often wrong, always useful. Design engineers going to the field to see a failure should have in mind a number of preconceived ideas (possibly conflicting) about what happened. It may be a waste of time to go to the field with an empty mind. But, of course, engineers must be prepared to change their mind based on the observations made in the field, and, when coming back to the office, must also be prepared to change their mind based on the analyses made in the office and/or in the laboratory.   Bologna 2000, pp. 110-111  

Most failures can be predicted using rational analyses based on principles of physics and mechanics, fundamental knowledge of geotechnical engineering, understanding of functions of geosynthetics, and a good knowledge of geosynthetic properties. Bologna 2000, p. 113

The design engineer who predicts a failure using rational analyses should believe the results of the analyses and convince other parties (i.e. the owner, contractor, etc.) that the failure is likely to happen. Bologna 2000, p. 113

Most failures are easy to explain, but some are difficult to predict. Therefore, engineers must learn from case histories describing failures. Bologna 2000, p. 113

Common sense, which indicates that adding a geosynthetic can only improve the performance of a structure, is wrong. An additional geosynthetic can be detrimental. Similarly, extending a geosynthetic beyond the area intended by the design engineer may cause a serious problem, because a geosynthetic may be beneficial in one area (where it is needed and specified) and detrimental in another area.  Bologna 2000, p. 88   

Adding a geosynthetic to an existing structure without reviewing the design may cause problems. Common sense, which indicates that two are always better than one, is wrong.  Two liners may be better than one only if precautions have been taken to prevent uplift of the upper liner. Bologna 2000, p. 96   

Learning from failures requires a strict intellectual discipline. Forensic analyses should be based on rational deductions conducted with Cartesian rigor. It is clear from many examples presented in this paper that common sense should not be used in forensic analyses. It has been shown in this paper that common sense is a random process that can have credibility only with those who prefer a veneer of satisfaction to the depth of understanding, and who prefer the comfort of illusion to the rigor of logic. To learn technical lessons, common sense is a common temptation that does not make sense. Bologna 2000, p. 116   

No opportunity should be missed to learn from experience. However, there is a great difference between experience and learning from experience. The only way to learn from experience is to analyze available data and incorporate the results of the analyses into an organized body of knowledge. Bologna 2000, p. 77   

Geotechnical engineering is an art as much as a science, as many like to say. This statement is incorrect and it may mislead those who are learning about geotechnical engineering. Geotechnical engineering is a science, it is not an art. It is a science because all phenomena of geotechnical engineering can be explained rationally. It is not an art because, in geotechnical engineering, there is no room for personal emotions and abstract imagination. Bologna 2000, p. 77

The fact that, in a scientific discipline, all phenomena can be explained rationally on the basis of first principles does not mean that all knowledge must result from logical deduction. In fact, a large fraction of the present scientific knowledge — and this applies to all disciplines — was generated from experience, often by chance. Rational explanations of the phenomena were developed eventually. This is particularly true for geotechnical engineering, a discipline where the complexity of materials, mechanisms and boundary conditions makes it difficult to predict phenomena only by pure logical deduction. Bologna 2000, p. 77