Control of Uncertainty in Geotechnical Engineering

The first requirement in the control of uncertainty in geotechnical engineering is an appropriate attitude of mind which accepts that uncertainty will exist even in the most controlled circumstances. Those whose understanding of geotechnics centres around the text book, analysis, and controlled laboratory experiments expect a foreseeable pattern of behaviour, a set of defined relationships between cause and effect. But the engineering behaviour of soils and rocks is not of this type; on the inscrutability of nature has been superimposed the technical and litigious limitations of man as revealed by the evolving practices of engineering design and the often irrational complexities of contractual relationships. The objective of this account is to attempt to identify and classify the nature and causes of uncertainty, followed by advice on strategy to contain it, illustrated by a number of examples of how this may be achieved (including how not to do it). Many of the principles apply broadly to many aspects of engineering.