As Michel Gambin leaves us, I remember our last conversation. With my friend Robert Heintz, we attended the Symposium “Charles-Augustin COULOMB: A geotechnical tribute” organized by the CFMS on 25 september 2023. At the end of the day, we decided to go to Michle’s home in Île Saint Louis, a short trip by Paris metro. Michel received us at length. Although very physically tired, we found him with his lively and vehement mind, always interested in all current geotechnical topics. In particular of course, we discussed the state of Pressuremetry, the progress of the ARSCOP works, the preparation of the next ISP8 Pressuremeter Symposium. Deep down for me, I hoped to benefit for a long time from his advice for this Symposium, he who actively participated and published in each of the past 7 Pressiometric Symposia, and who gave a great impact in 2005 to the fifty years of the Pressuremeter.
Among all of Michel’s professional qualities, which all members of the ICP know well, what has always impressed me is his infallible vision of the right direction to give to Pressiometry. Every time I wrote with him, in fact, I wrote for him, a habit I had adopted since he hired me at Ménard. He always knew how to decide very quickly: “this must be dealt with elsewhere, not in this paper; this must be established first and developed; you condense this and repeat it in two sentences maximum, etc.”
This power of work and this capacity for rereading, he applied it during all his life: alongside Louis Ménard, writing down and disseminating the fundamentals of Pressiometer, by creating and animating with Jean Rousseau the magazine Sols-Soils, by creating the corpus of “D” Ménard notices, including notice D60 initially published in English by Louis Ménard and which remains at the root of all standards of foundation design with the Pressuremeter. He is the one-man orchestra for all the technical, scientific and commercial documentation of Louis Ménard’s group. From the start of this publishing activity, he kept a press review of important geotechnical works, as he continued to do years later by creating and animating the Lettre de la Géotechnique for the CFMS. Simultaneously, he created the concepts of pile settlement, he supervised the development of increasingly precise pressure-volume controllers, he was at the initiative, even before the premature death of Louis Ménard, of the first attempts at digitalization and automation of pressuremeter measurements, which he will then relaunch at Apagéo. After the death of Louis Ménard, he was at the origin at Solétanche of the evolution of dynamic compaction from Louis Ménard to dynamic consolidation, and also interested in all forms of soil improvement, jet-grouting, compaction by explosives, and the fundamental concepts underlying them. His correspondence with all the big names in geotechnics in the world is continuous throughout the 70 years of his professional career, many of you know his handwriting, as clear in substance as in form, often imperative and carrying conviction, and that it will always continue in parallel with the advent of electronic mail. In this scientific, editorial and epistolary activity, he signs, a bit like a Doctor Jekyll & Mister Hyde of the Pressuremeter: Michel Ph. Gambin, Mike Gambin, Michael, gambin@magic.fr or simply Michel.
This strength of conviction, throughout his career, he will use to lead the training of Pressuremeter dealers franchised by Ménard, to participate whenever he has the opportunity in presentations, conferences, training on the Pressuremeter methods, then on his retirement teaching at the University of Paris-Jussieu and at the CNAM. In retirement, he never will be, immediately throwing himself into the training and direction of the CEN/TC341/WG5 “Borehole expansion tests” working group, which became ISO/TC3182/WG8, and continuing to publish on the Pressuremeter, the soil improvement, and argue with geotechnicians who do not apply or apply poorly in his opinion the fundamental principles of soil behavior.
What I also learned with Michel Gambin is to never forget, in professional geotechnical practice as in scientific research applied to soils and rocks, the experimental method and the lessons to be learned from the daily practice of tests and work in the soil. And then take the experimental results into account before any theoretical a priori to understand the behavior of soils, while tirelessly seeking to explain as completely as possible the phenomena correctly observed by the fundamental laws of nature both geological and geomechanical.
This is the meaning of one of Michel Gambin’s last major contributions, during the Coulomb conference he gave in 2010 “Theories and their evolution in the face of reality in Geotechnics”. Reading the 152 slides shows both his immense mastery of the concepts of continuum mechanics, from Coulomb to Terzaghi who was his teacher, and the admiration he retains for the audacity of Louis Ménard when together they abandon the dogmas of their predecessors to trust in direct design based on their first pressuremeter tests and their tests on full-scale foundations.
We have just lost with Michel Gambin, collaborator and diligent developer of the dazzling career of Louis Ménard, an “honest man” who marked the evolution of the geotechnical profession, after having been the student of one of the last years of teaching of Karl Terzaghi, founder of our profession.
Jean-Pierre Baud