Geotechnical Engineering Journal of the SEAGS & AGSSEA ISSN 0046-5828
Vol. 47 No. 3 September 2016
7th Lumb lecture 10th October 2012 “Peter Lumb’s legacy, Soil Mechanics = Simple concepts + mathematical processes + lateral thinking”
By John Endicott
SYNOPSIS: Professor Peter Lumb’s legacy to the Hong Kong geotechnical engineering profession was 32 years of service at the University of Hong Kong. For this he is fondly remembered by his many students as a quiet teacher, a contemplative man. The majority of his time Peter had grappled with tropical weathering and its consequence in engineering properties as well as the performance of soils and rock in an industry that was mostly not very enlightened for some 24 years before the Geotechnical Control Office (GCO), was established.
In his early days reliable laboratory testing was not common. Peter built the first testing laboratory in Hong Kong . Computers were under development and not in use. Peter taught assessment, insight and auditable hand calculations. Faced with a heavily regulatory system designed to compensate for inadequacies of the not well informed amongst the practitioners, he shied away from getting involved with day to day projects. As a profound thinker, when Ken Roscoe at Cambridge University was working on Critical State Soil Mechanics and Alan Bishop at Imperial College London was trying to perfect uni-axial compression tests, Peter realised that statistics was a means of handling variation, uncertainty and risk. Like some other geotechnical people, trained to investigate, he branched out into a new field and became a worldwide specialist in statistical theory not related to applications to soil mechanics.
He retired 26 years ago. What have been the fruits of his legacy? The most obvious results are dozens of his former students who have carried on his tradition, not necessarily in soil mechanics, and have achieved high positions and led worthwhile lives. The industry has changed. Testing laboratories are accredited. Deep excavations with lateral support and foundations are designed rationally. Much reclamation have been completed without the mud waves of the kind that were generated in the 1970’s. Thanks to the efforts of the Geotechnical engineering Office (GEO), landslide risk has been significantly reduced. The subject of stability of slopes is complex and there is fascinating on-going research into the performance of slopes. Computers are taken for granted. Computations can be carried out quickly and more intricately than he imagined. Mathematics was a predictive tool, now it is hidden behind icons which can be invoked without thought.
Mathematics has been a principal tool behind the soil mechanics that Peter taught. Coulomb and Terzaghi were mathematicians. However solutions have given place to processes. Numerical modelling is very useful and is now made freely available to engineers. The collapse of the Nicholl Highway in Singapore was initially blamed on the mis-use of numerical modelling. Within limits debris flow can be analysed but prediction of flow remains difficult. Numerical models can predict slopes moving uphill in the dry season.
Statistics are being adopted to a limited degree. Quantitative Risk Assessment and Fractal Analysis require large supplies of relevant data. Today gigabites of data are transmitted in minutes. One wonders whether Peter would have approached statistics in a less theoretical way had he been working 26 years later?
Geotechnical Engineers file data spatially as Geographic Information Systems (GIS). Very much as Peter thought laterally and was attracted to statistics likewise GIS people, thinking laterally, have moved into asset management and a variety of other fields.
The legacy of Peter Lumb lives on; it is the better side of human nature.
KEYWORDS: 7 th Lumb Lecture, 10th October 2012Peter Lumb’s Legacy, Soil Mechanics, Simple Concepts, Mathematical Processes, Lateral Thinking
