It can be tempting to jump straight into the geotechnical aspects of a project without thinking about the bigger picture. Pressures for space mean that more developments are moving to marginal land such as soft soils, slopes, waterfronts and brownfield sites, each with their own particular set of geohazards. Rising land values and increasing congestion are making underground development more attractive. However, careful planning and efficient foundation designs are needed to reduce potential constraints for future development and the impact that these can have on land values. Cities that have undergone a number of cycles of redevelopment highlight the problems that we will face in the future, and the increasing need to consider the reuse of existing foundations. Reductions in risk can be achieved through publically available borehole databases and the transfer of site investigation data in standard electronic formats. Geothermal energy is often considered, but simpler methods of thermal energy storage exist, for example using pile foundations, and these present opportunities for significant savings in energy costs.
This presentation describes geotechnical issues that should be considered, but are often forgotten, drawing from the work done in the European Commission’s COST C7 committee described in the book “Hidden Aspects of Urban Planning” co-authored by the presenter and published by Thomas Telford. Numerous examples of international best practice in geotechnical engineering and underground space development will be described, along with two case histories of foundation reuse in London.
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