(Portions of this essay were first published in Ralph B. Peck, Educator and Engineer.)

No one has had the impact on the geotechnical profession that Ralph Peck has had over the last 50 years, and it was sustained through the last years of his life. Peck, who died in February at 95, was a pioneer in the development of the discipline of soil mechanics — now geotechnical engineering — and its application to engineering practice, and he continued throughout his 70-year career to serve as teacher, mentor, and guide as the profession matured. He co-authored two of the most influential textbooks in geotechnical engineering, Soil Mechanics in Engineering Practice (1948) and Foundation Engineering, (1953), and authored over 250 technical publications. He continued to actively write and give keynote lectures in the past 10 years, as is evidenced in the recent volume Ralph B. Peck, Educator and Engineer (Bi Tech publishers, 2006), in which Peck describes his life and career and provides introductions to a series of papers and lectures.

Peck enrolled at Rensselaer Polytechnic University, earning his civil engineering degree in 1934 and doctor of civil engineering degree in 1937. In 1938 he studied under Arthur Casagrande at Harvard, learning about the new discipline of soil mechanics. There, Karl Terzaghi, a consultant for the Chicago Subway, asked Peck to move to Chicago to set up a soils lab and carry out a program of field measurements and observations during construction of the tunnels and excavations.

Peck joined the faculty of the University of Illinois in 1942. He retired from the University in 1974, and, for the next 32 years, he returned each semester to give three lectures to the civil and geotechnical engineering students. Throughout his career, he was a practicing engineer and an educator; the two were inseparable. He taught his students the practice of engineering and he educated practitioners as he participated on projects and in professional forums.
During the 1989 University of Illinois geotechnical symposium honoring Ralph Peck, Professor Herb Ireland recalled his early years at Illinois — the 1940s and 1950s. Professor Peck would take Herb and other grad students into the field — hand-augering glacial deposits in Illinois, investigating landslides in marine clays in Quebec, inspecting caissons and designing foundations in the Chicago clay. They saw how Professor Peck approached the project, how he observed soil properties and ground behavior and how he solved engineering problems. Herb concluded that those of us who came later had missed a major part of our education.

In the early 1960s, when I was in grad school at Illinois, Peck was at a point in his career where he was not taking students out into the field. But I disagreed with Herb Ireland; we were not unfortunates who had missed an essential learning experience, because Professor Peck provided it to us in the classroom.

I believe that Ralph Peck considered teaching the most important part of his university life. He believed that judgment, or its foundations, could be taught, and wrote: “There is actually such a thing as engineering judgment and it is indispensable to the successful practice of engineering,” and “Theory and calculations are not substitute for judgment but are the basis for sounder judgment.” His case histories course was well known because it was such an unforgettable learning experience. It was as interesting as any detective story — going to the site, observing clues, listening to the construction workers — solving a puzzle with many pieces but always some missing. Professor Peck would describe his first contact with the client and then let the classroom “Board of Consultants” guide him as they walked through the project with him. At the end of the course, each student felt as though they had added ten projects to their resumes and had been in the field with Professor Peck, learning how to approach the project, make critical observations, deal with the uncertainties and variability of the site, evaluate the key issues and make engineering decisions.

His consulting practice encompassed the breadth of geo-engineering, and he was engaged on over 1,000 projects around the world, but it is appropriate to focus on his work in tunneling, because he always considered it one of the most challenging and interesting geotechnical endeavors. In 2006 he stated: “My most abiding interests in geotechnics are probably divided between embankment dams and tunnels. Because I was introduced to the practice of tunneling with the Chicago subway experience, tunnels have been a very large part of my consulting activities all of my life.”

The Chicago Subway project in 1939-42 served as a proving ground for soil testing and field measurements in urban excavation and tunneling. Strut load measurements were the basis for the earth pressure envelopes used in the design of braced excavations. Unconfined strength tests and mapping of the variability of the soft clay deposits in the tunnel heading were used to evaluate stability and requirements for compressed air. In the liner plate tunnels, rods driven into the tunnel face and walls were surveyed to measure the volume of ground loss. The measurements were correlated with observation of excavation and support cycles and construction details, and the results were linked to the volume of the surface settlement trough so that the causes of excessive settlement could be determined and corrected.

Other tunnel projects followed, including the Garrison Dam Test Tunnel, the Wilson Tunnel in Hawaii and the BART subway tunnels and station excavations in
San Francisco bay mud. His state-of-the-art paper “Deep Excavations and Tunneling in Soft Ground” at the 7th International Conference on Soil Mechanics in Mexico City, was a landmark paper on assessing and evaluating ground movements and settlements around tunnels and braced excavations.

It was on the Washington Metro in the early 1970s that I first had the opportunity to go into the field with Ralph Peck. I was a young faculty member at the University of Illinois conducting field research on the Phase 1 soil and rock tunnels and excavations. Peck was on the Board of Consultants for Deleuw Cather, the general engineering consultant to Metro. He made it a point, early in the morning prior to board meetings, to walk through the construction sites with our research team, observing the current construction and ground behavior, and listening to us.

One bright, winter morning in Washington, I, with Bill Hansmire, picked Ralph up at his hotel and visited the soft ground shield driven tunnels that were the subject of Bill’s Ph.D. thesis. We came out of the shaft, crossed Pennsylvania Avenue in front of the White House and walked to our array of extensometers and inclinometers in the middle of Lafayette Square. There we discussed our results in the context of Ralph’s experience that went back to his investigations on the Chicago Subway in 1940. What a valuable experience those visits were for us, but I suspect that he valued them as well. No matter how many board rooms he has sat in over the years, Ralph Peck’s priority has been to go to the site, observe and listen.

Of the many awards he received over his career, including the National Medal of Science from President Gerald Ford in 1975, he was particularly honored to receive The Moles Award for Outstanding Achievement in Construction in 1973. It meant a great deal to him to be given an award by those who work to build underground projects.

Dr. Edward J. Cording is Professor Emeritus, University of Illinois, at Urbana-Champaign. He is also a recipient of The Moles Award for Outstanding Achievement in Construction, 2003.