Sir Alec Skempton is often referred to as one of the founding fathers of soil mechanics in the UK and, as 2014 is the centenary of his birth, GE looks back at the life of this industry’s leading pioneer.
The name Skempton is synonymous with soil mechanics, not just in the UK, but around the world and that is not without good reason. In the 100 years since Sir Alec Skempton was born, the field of soil mechanics has gone from a concept to a well-established science.
Skempton not only helped to drive forward understanding of soil behaviour through his research and consultancy work but also to inspire successive generations of engineers through his teaching. His love of engineering history also played a significant role in increased understanding of the design of the UK’s early infrastructure network and his forensic analysis of the failures further added to ground engineering knowledge.
Despite his impressive achievements over a career that spanned more than 60 years, Skempton’s path into the field of soil mechanics was not a straightforward one. In his early school days his focus was on the classics and, even when he moved schools, he admitted to being “bone idle” and only a stern talking to by his mathematics teacher led to him applying himself to his studies.
Skempton took up a place at Imperial College in 1932 to study civil engineering and it was during his second year that he was introduced to geology. “I fell in love with it and thought it was a beautiful subject,” he said.
Nonetheless, it was reinforced concrete research that Skempton turned his attention to when he graduated in 1935, and he started work on a PhD with the aid of a Goldsmith’s company bursary. He joined the Building Research Station (BRS) to continue his research, but once there he became aware ofthe newly formed soil mechanics section that had been formed by Leonard Cooling. Skempton’s interest was piqued and he stopped work on his PhD, accepting an MSc for the work he had already completed, and joined Cooling’s new section in January 1937.
Skempton was virtually at the birth of the subject of soil mechanics in the UK and his observations following collapse of the Chingford
Reservoir embankment dam just a few months later were to seal the focus of his career.
Initially, the cause of failure during construction at Chingford was a mystery because the dam had not reached the full height of the nearby King George V reservoir, which had showed no sign of instability in the 25 years since completion. It was Skempton who spotted that the dam had failed due to the speed of construction.
The King George V reservoir had been built using horses and carts giving the underlying alluvial clay time to consolidate properly whereas the clay under the Chingford dam was only partially consolidated as a result of the speed of construction from using modern earth moving machinery.
It was at Chingford that Skempton first came into contact with Karl Terzaghi, who was called in by the contractor to redesign the dam, and he later referred to Skempton as “one of the most promising stars on the horizon in our field”.
Chingford was the first of many embankment dams that Skempton advised on. In 1940, the Muirhead dam failed due to lack of adequate consolidation and its investigation led Skempton to propose the acceleration of consolidation by the radical idea of incorporating sand drains within the embankment - a technique that was first used on Chew Stoke dam in the early 1950s with great success and has been almost universally adopted.
More recently Skempton, at the age of 70, was called in to investigate the failure of Carsington dam which occurred in June 1984 when the embankment had been built to within 1m of its full height of 25m - fortunately before filling had commenced. The dam had to be demolished and was redesigned with Skempton acting as an adviser.
It is largely due to Skempton’s work on soil mechanics through his involvement in the Chingford incident that the subject became recognised as an essential discipline of civil engineering alongside structures and hydraulics. Skempton helped to reinforce this by establishing the UK’s first at Imperial College while on part-time secondment from the BRS in 1945.
The following year he became a full-time lecturer and after establishing a post graduate course in soil mechanics in 1950, he became professor of soil mechanics in 1955 and headed up the department of civil engineering from 1957 until 1976 before retiring in 1981.
Although he maintained strong links with Imperial as an emeritus professor and senior research fellow until just a few weeks before he died in 2001, much of his focus after retirement was on engineering history.
Although he always retained his enthusiasm for historical geotechnical case studies, his major historical contribution was the study of the work of early civil engineers, especially those of the 18th century, whose achievements had been ignored by previous engineering historians. His work on John Smeaton, John Grundy and William Jessop are considered of particular significance.
Skempton’s historical research also proved beneficial to modern engineering design. His two papers to the Newcomen Society on the construction of the early 19th century docks in the Port of London were written around the time that the redevelopment of Docklands was about to get underway, and provided a ready source of reference for engineers unfamiliar with the engineering practice of the time. More recently, the 150th anniversary of the completion of Marc Brunel’s Thames Tunnel in 1993 coincided with London Transport’s interest in upgrading the East London line, of which it forms part.
His final historical work was as chairman of the editorial board for the publication of A Biographical Dictionary of Civil Engineers in Great Britain and Ireland B Volume 1: 1500-1830 which was published in the autumn after his death on 9 August 2001.
He was knighted in the Millennium Honours List, which gave him and his many friends much pleasure, but he is noted to have remarked: “Mind, you are still to call me Skem”.
In the centenary of his birth, Skempton’s impact on the field of soil mechanics is still very clear and he is remembered with affection by many of those who worked alongside him or who studied under his tutelage.
GE would like to thank Mike Chrimes and John Burland for their assistance with the writing of this profile.
1957 Succeeded Terzaghi as president of International Society of Soil Mechanics and Foundation Engineering (now ISSMGE)
1961 Elected Fellow of the Royal Society
1974-76 ICE vice-president
1976 Founding Fellow of the Royal Academy of Engineers
1981 Gold Medal of the Institution of Structural Engineers
2000 Gold Medal of the Institution of Civil Engineers
2000 Knighted in Millennium Honours List