John Mitchell Lecture 2021: A Career Embedded in the Ground

Overview

The John Mitchell award was instituted in 2008 in memory of the prominent geotechnical engineer John Mitchell of Arup, who was killed while observing piling works at a central London site in 1990.

This event is run jointly with the British Geotechnical Association (BGA). They are an associated society supported by ICE. This is an annual event, with 2021 marking its 14^th year. The winner of this award gives the John Mitchell Lecture the following year.

The award criteria considered by the BGA include the following:

• In reflection of John Mitchell’s career, selection will favour practical applications of up to date geotechnical concepts or models (rather than advanced theoretical academic practice)
• The BGA will consider individuals, like John, who in the course of their careers via incremental works have made significant contribution to geotechnical practice
• Notwithstanding the above, the BGA will in addition consider any contemporary practitioner who has instigated a major advance in the geotechnical field, thus opening the award up to the innovative, regardless of age or incremental contribution count

Topic: Technical competence as the primary attribute of an engineer, embedded in a geotechnical context, and the role of the engineer in projects and business.

Drawing on his geotechnical design experience, the first part of the lecture will concentrate on technical aspects; technical competence being the primary attribute of an engineer. David Beadman will discuss the forces imposed on embedded retaining walls from the retained ground and ground water, comparing theoretical and measured values. This will include specific examples from two key projects that he worked on in mid-career: The Jubilee Line Extension Project and the Copenhagen Metro.

Several examples of pile design and performance from more recent projects will be reviewed, providing some avenues for future research. After several years of presenting courses for Thomas Telford on Geotechnical Design to Eurocode 7, and many years of using the code in practice, David will reassess the partial factor approach to ultimate limit state geotechnical design. This section will conclude with a discussion on ‘value engineering’.

The second part of the lecture will broaden the subject matter to deal with some of the additional topics that are included as part of the Chartered Professional Review, discussing the role of the engineer in projects today and the role of the engineer in business. Important decisions about the procurement route and the type of contract are made at an early stage of civil engineering projects which strongly influence the outcome of the contracts. This will be discussed, based on David’s personal experience, assessing the apparent success or otherwise of different contracts.