Geotechnical considerations in brownfield redevelopment

This chapter provides a systematic examination of the principal geotechnical considerations arising in brownfield redevelopment, addressing the technically complex challenges that distinguish previously developed sites from their greenfield counterparts. It begins with the engineering behaviour of made ground encompassing its heterogeneous composition, high compressibility, collapse and expansive potential, and the hazards posed by buried structures and anthropogenic voids before examining the often-neglected interaction between chemical contamination and soil geotechnical properties, including the effects of non-aqueous phase liquids, heavy metals, and sulphates on soil strength, compressibility, and construction material durability. Phased site investigation strategies appropriate to brownfield heterogeneity are discussed alongside formal geotechnical risk assessment methodologies, including probabilistic parameter evaluation and the Observational Method. The chapter then evaluates foundation and earthworks design options shallow foundations, piled solutions, and ground improvement offering comparative analysis informed by site conditions, contamination status, and structural sensitivity. Retaining structure design, slope stability in fill materials, and construction monitoring are also addressed. The contribution of emerging digital and geophysical technologies including three-dimensional geological modelling, machine learning-assisted data interpretation, and UAV remote sensing to improved subsurface characterisation is considered alongside sustainability principles relating to material reuse within a circular economy framework. Throughout, the chapter emphasises the indispensability of integrating geotechnical and geoenvironmental assessment and situates practice within the UK regulatory framework of BS 5930, Eurocode 7, and contaminated land legislation.