Chapter 7: Geotechnical risks and their context for the whole project

This chapter provides an understanding of how project developers consider construction projects and their huge vulnerability to project delays, and when it can be profitable to proceed with a development. By example, it shows the proportion of geotechnical-related costs for a typical London office project and compares those costs to the tiny investments in geotechnical risk mitigation by desk study and ground investigation. It explains that geotechnical risks can be ‘wildly random’ instead of ‘mildly random’ and so the consequences of a problem can be hugely disproportionate to the initial cost. It compares typical frequencies of ground-related problems and finds that even the average cost of mildly random problems have consequences that far outweigh the very modest cost of a good ground investigation. It concludes that management of geotechnical risk by contingency is an approach fraught with peril and that management by mitigation is much more likely to produce the desired outcome.