Technical Committee 207 ISSMGE “Soil-Structure Interaction and Retaining Walls”, of which I have been honoured to be the Chairman since 2005, has organized eight conferences and special sessions in Saint Petersburg, Ghent, Moscow, Rostock, Dubrovnik and Paris.

This conference which is taking place during the white nights in Saint Petersburg is dedicated to the memory of an outstanding geotechnical expert Gregory Porphyryevich Tschebotarioff.

Gregory Porphyryevich Tschebotarioff is mentioned in all encyclopaedias as a Russian-American scholar, a specialist in soil mechanics and foundation engineering. He was born in February 1899 in Pavlovsk. His parents owned a splendid residential house in Tsarskoe Selo, a suburb of St. Petersburg.

In light of several inconsistencies in his subsequent biography I would like to clarify certain moot points based on archive materials found in St. Petersburg and specifically in the library of Saint Petersburg University of Transport, formerly known as Alexander I Institute of Transport, founded in 1809. In 2014 Saint Petersburg University of Transport regained its association with the name of that benevolent Russian Emperor Alexander I, known by many to have been its founder. This oldest establishment of education in the field of technology is also inherently connected with the name of Gregory Porphyryevich Tschebotarioff.

Gregory Porphyryevich Tschebotarioff was born not simply in the family of a Cossack officer. His father was especially close to the Russian Emperor's family, as can be now stated unequivocally, whereas his wife and mother of G.P. Tschebotarioff served as a lady-in-waiting to the Empress. Prior to the October Revolution of 1917 his father was in the rank of lieutenant-general serving in the Guards of the River Don Cossack Regiment. And one more interesting touch: G.P. Tschebotarioff's godmother was the Dowager Empress, the mother of Tsar Nicholas II, who was deposed after the 1917 uprising.

Gregory Tschebotarioff's first wife was Lydia Fyodorovna Krasnova, who prior to their marriage was a young friend of Tschebotarioff's mother and resided in Detskoe Selo (currently a town of Pushkin, a suburb of St. Petersburg mentioned above). She was close to the emperor's family even through the location of her house. It was natural that generals true to the emperor, like Tschebotarioff or Krasnov, Grigory's father in law, as well as the historic River Don ataman Kaledin, felt it a call of duty to preserve Russia's integrity by being victorious both against Germany and inside Russia itself, at the time embroiled into Bolshevik revolts, which the remaining army tried very hard to quell. Those included the well-known mass uprising on the River Don. Subsequently the forces of the so-called “Volunteers” or the White Army were fighting battles with the Red Army Corps, initially victorious but later largely unsuccessful. The last stronghold of the whites on the River Don was the city of Novocherkassk. Allegedly, it was there that Grigory Porphyrievich ended his military career. Here I would like to mention several interesting moments from the highly eventful revolution months of 1917–1918. The young Gregory Porphyryevich, having barely turned 18, was appointed a personal aide to general Krasnov, one of the combatants against the Reds in 1917–1918 in Russia. Being an expert German translator, having legal, albeit secondary education, Gregory took part in the famous talks between Krasnov, Trotsky and seaman Dybenko, which were attended also by the German military.

Now let's move to a bit of historical data, establishing the fact that his legal education began at the age of 12 when he joined the Imperial Law School. It was already during the war that he finished a concise course at Mikhailovsky Artillery School and graduated in 1916 in the rank of corporal. It was thus impossible for him to have been one of the leaders of the Whites' opposition neither in St. Petersburg nor on the River Don, as is sometimes believed. He doubtless must have felt deeply for them, but his chosen career at that turbulent time for Russia was that of a civil or transport engineer.

Here I have in front of me a copy of G.P. Tschebotarioff's inscription and signature on a book on soil mechanics published in the USA and presented in 1973 to professor Vladimir Petrovich Sipidin at the Department of subsoils and foundations of St. Petersburg Transport University (Figures 1 and 2). Therein Gregory Tschebotarioff designates himself a student who entered the Transport University in 1918. The inscription states that the book is being presented to be read and subsequently donated to the university library.

The full title of the book is “Foundations, retaining and earth structures”. I am a member of the international community of geotechnical engineers united today by the ISSMGE, and I am really happy about the fact that G.P. Tschebotarioff had chosen his professional career at our Transport University and that amongst his colleagues, professors of soil mechanics, to whom he would subsequently present his books, were representatives of our department at St. Petersburg. Moreover, he held Russian specialists, and particularly geotechnical engineers, in high regard. Having worked in the USA for a long time he condemned politically engaged distortions of Russian history published by the USA media during the McCarthy era at the time of the so-called “cold war”. It is officially known that during exchange of scientific delegations between the USA and the USSR Professor Tschebotarioff declined certain advances on the part of the CIA. Moreover, as a sign of protest he turned down the Professor Emeritus rank at Princeton. Another reason for that reaction were cases of persecution of professors of Slavic nationalities, particularly those teaching the Russian language and literature. This gives us a man of a very broad range of attention in the areas of both science and humanities.

All this does not quite endorse the image of a leader of Whites' opposition to the Reds on the river Don. At the age of 19 in 1918 he opted to come to St. Petersburg and enter the University of Transport which he could not graduate from for purely political reasons, being a member of a family close to the Russian Emperor, who were at the time being persecuted by the Soviet law enforcement agencies.

Having spoken to my senior colleagues from the field of soil mechanics and construction I confidently can bring to your attention the following moments from Gregory Tschebotarioff's youth. After entering the University of Transport he understood quite clearly that his social origins could lead to quite dramatic consequences. He was aware of what was being done to his colleagues – officers from famous St. Petersburg families, but the wish to become a professional civil engineer prevailed over the sense of self preservation danger. According to the famous professor of St. Petersburg University of Architecture and Construction (St. Petersburg Institute of Civil Engineering) and St. Petersburg Transport University Vladimir Alexeevich Gastev and professor Victor Anatolievich Florin, Gregory Tschebotarioff was interested in soil testing research in the Laboratory of Soil Mechanics at the Transport University. At that time the laboratory supervisor was the famous Russian and subsequently American professor S.P.Timoshenko. I am convinced that their ways crossed whilst still in St. Petersburg: it was in that oldest mechanical laboratory that N.M. Gersevanov conducted his pile tests (a graduate of the Transport University of 1902 and son of the rector of the University who served in that capacity for more than 25 years). Subsequently, the leading and one of the largest specialized underground construction and foundation engineering institutes in Russia was named after N.M. Gersevanov (known today as Moscow NIIOSP). Among his student contemporaries there were N.N. Maslow and V.A. Florin who subsequently having become leading geotechnical specialists of world renown served as translators of papers and monographs by G.P. Tschebotarioff published in the USA. One can say quite confidently that since the very first days of his study at the University of Transport, being in contact with a constellation of future geotechnical gurus (S.P. Timoshenko, V.A. Gastev, N.N. Maslow, N.M. Gersevanov), he could not help getting engaged into geotechnical science which was at the time at the breaking point in terms of its importance for construction practice, and not only in Russia. He continued to maintain his ties with those bright minds also in his late years. The present writer was not spared the “geotechnical bug” that tied him to the circles of people engaged in soil mechanics after attending lectures by professor N.N. Maslov in 1957 in St. Petersburg. I was at the time a cadet of the military faculty at the University of Architecture and Construction (former Institute of Civil Engineers, later known as LISI).

According to Prof. N.N. Maslov young G.P. Tschebotarioff arrived to Berlin Technical School with notes on lectures by S.P. Timoshenko on theory of elasticity and books including publications by the Transport University Press presreved in his personal library. He profoundly impressed the examination board having presented to them his Russian knowledge in the German and English languages. According to his own testimony, Gregory Tschebotarioff had free and lengthy conversations in those languages with the members of the board and the invited leading civil engineers from the Berlin Technical School.

Sadly, fear for his life never left G.P. Tschebotarioff during the war years after the October Revolution in 1917, even after his departure to the south of Russia. Those fears were especially reinforced after he found out that some people known to him were imprisoned after their arrests and the military officers arrested in those years were loaded on ferry boats and drowned in the Gulf of Finland. This information is contained in his memoirs. I read about a lot of similar facts in Tschebotarioff's book entitled “Russia, My Native Land” published in New York in 1964 by McGrow-Hill Book Company. From this book I learned that his grandfather, whose name was also Gregory Tschebotarioff, was of Cossack stock and, a graduate of the Paris Institute of Technology, was in charge of railway construction in the South-East of Russia connecting the cities of Rostov and Voronezh in late 19th – early 20th centuries, whereas his mother Valentina Ivanovna during the war was a nurse in the military hospital at Tsarskoe Selo, where at this time the Empress Alexandra Fyodorovna was also engaged in a similar capacity. Gregory Tschebotarioff doubtless was in contact with them – his mother and his god-mother, during his sojourn while on leave in 1917 at Tsarskoe Selo, where his family resided at the time.

Initially it was with a certain degree of reluctance that I read sections on G.P. Tschebotarioff's life not connected to soil mechanics and foundation construction. But those five chapters read like an adventure story resembling “The Road to Calvary” by Alexey Tolstoy. G.P. Tschebotarioff was frequently arrested in the south of Russia but he was lucky “not to have been shot” as he himself put it in the book. Once he was mistaken by the Reds' patrol to be a “Whites' guerrilla fighter” due to a typical white officer's knapsack he was wearing, but he was spared by the timely benevolent intervention of a high-ranking official of the Reds who happened to be a former officer of the Imperial Russian Army, and a native St. Petersburger. He quietly talked to Gregory Tschebotarioff and in spite of violent protests from the blood-thirsty revolutionaries let him go. The second arrest was even more dangerous but he had time to conceal himself from the arresting brigade in the huge crowd of pro-revolutionary populace greeting the arrival of the Red Leaders to the city of Novorossiysk. In such environment of constant threats the only solution left for him was emigration. He was evacuated to Egypt together with the College of the Don Cadets where he worked as instructor since 1921, acting as an aide to the Artillery Inspector of the Don Army. We will not be far from the truth supposing he instructed his officers in the matters of construction science because construction was the only practical field where disciplined Russian officers were in high demand, organizing and conducting building activities – there were simply no other activities ongoing in Egypt at that time.

After graduating as a civil engineer in Berlin, Gregory Tschebotarioff worked in Egypt. Demanding ground conditions of that country alerted him to the issue and importance of soil mechanics in general, and to complicacy and responsibility of foundation construction in particular. He served as a consultant in these areas for some time in France, Germany and the USA. As of 1937 he became a fulltime professor at Princeton, holding a tenure in the art of construction. It is interesting to point out that directions connected to soil mechanics and foundations, including stability of retaining structures were quite rightly regarded as construction art. Gregory Tschebotarioff was involved in projects related to construction of bridges, high dams, tunnels and other civil and military structures, some of them being unique.

I would like to point out the following moments from Gregory Tschebotarioff's notes which infused our work in ISSMGE TC 207 “Soil-Structure Interaction and Retaining Walls” for eight years (2005–2013):

– he alerted the scientific community to instances of serious discrepancy between results of large-scale and expensive in situ tests and calculations, including those behind recommended values in design standards and construction codes;

– he objectively reviewed hypotheses and theories propounded by various authors and prevalent at the time openly challenging instances of inconsistency and obsolescence;

– he reinforced understanding of soil mechanics as the theoretical foundation for calculation and computation paying specific attention to soil tests as capable of clearer representations of stressed-strained conditions in soils and structures of any degree of responsibility;

– in his book “Soil Mechanics, Foundations and Earth Structures” Prof. Tschebotarioff provides a lot of numerical data and gives a large number of numerical examples as compared to calculations according to various theories.

Below follow some highlights from a section of his book entitled “Interaction between structures, foundations and subsoils”. Here is a direct quotation: “The bearing soil beneath a foundation, the foundation itself and the superstructure form a connected system and must therefore be always viewed as a unified whole”. This premise was in the past too often ignored and is still sometimes overlooked by individual authors. All of it is largely connected to the complicacy of the actual problem, which was impossible to calculate efficiently with the old mathematical toolbox, that is to say without the computerized numerical modelling capabilities. Even today, theoretical background lags somewhat behind the actual contemporary construction practice, in which we have witnessed mega-deep underground structures and super-tall skyscrapers over 1000 meters tall.

Reviewing his quotes about calculations and in situ measurements one may conclude that Gregory Tschebotarioff was and has remained an ideologist for the activities of our contemporary Technical Committee No207 (Soil-Structure Interaction and Retaining Walls) of ISSMGE, which I was fortunate enough to head for eight years (2005–2013), and which was hosted by Russia and the Transport University.

Without looking down on the SSI related research of my contemporaries, it is important to point out the significance of Prof. Tschebotarioff's ideas which he even in his day and age communicated to colleagues whilst a delegate to almost all congresses and conferences of ISSMGE (whose abbreviation certainly changed a number of times over the years), starting from the first 1936 congress in the USA. He frequently chaired sessions and sections, as well as working committees on stability of retaining walls and underground structures.

In 1958 the USA and the USSR exchanged delegations of scientists and engineers. As member of the American delegation Gregory Tschebotarioff visited Moscow, Leningrad, Kiev and Stalingrad. He summarized his impressions in the following words: “I was leaving with a happy feeling that my motherland – Russia – was alive and recovering after the terrible ordeals which it had had to suffer”.

Concluding my account of the life of a world-famous geotechnical specialist Gregory Tschebotarioff, who started his career as a student of the St. Petersburg Transport University in 1918, and developed into a great specialist at Princeton in the USA, it is relevant to address a possible question from my geotechnical colleagues as to why it was that the members of TC 207 “Soil-Structure interaction and retaining walls” suggested a lecture dedicated personally to Prof. Gregory Tschebotarioff. I believe that soil-structure interaction was the leading element in his works and, additionally, extensive systems of monitoring on large scale projects in the USA assisted his evaluation of integrity of calculations and in situ tests.

The two sessions allowed to TC 207 “Soil-Structure Interaction and Retaining Walls” at the 18th International Conference on Soil Mechanics and Geotechnical Engineering in Paris in 2013 hosted about 1350 conference delegates, which demonstrates importance of our field to the geotechnical community. We enjoyed record attendance figures, which was pointed out in the concluding speech by the newly elected ISSMGE President Roger Frank (France). All significant construction projects over the last 10 years have broadly implemented systems of mathematical modelling in design, during construction and in subsequent monitoring. This was conducive to unification of “the three elephants” who serve as foundation for our profession both in new construction and in reconstruction. The three elephants in question are the architect, the superstructure engineer, and the geotechnical engineer. The reports at TC207 SSI sessions in Paris presented bold achievements implemented in design of supertall structures (over 1000 m) constructed in Dubai, as well as in other unique structures using state-of-the-art software engineering solutions and contemporary construction codes (Proceedings of the TC207 workshop on soil-structure interaction and retaining walls – September 2013, Paris – www.paris2013-icsmge.org).

The geotechnical engineers of the new century have reached a new stage in numerical calculations using advantages of contemporary computing, i.e. such as were simply not there before. This disadvantaged level of calculation methods troubled Professor Gregory Tschebotarioff and burdened him greatly, which he openly wrote and spoke about.

In conclusion I would like to quote our newly elected ISSMGE President Professor Roger Frank: “The perspective of contemporary codes for geotechnical design will be grounded in three words: “SOIL-STRUCTURE-INTERACTION”!"

Chairman of TC207 ISSMGE (2005–2013)

Professor V.I. Ulitsky (Russia)