Design and construction considerations

Relict glacial and periglacial environments are widespread, and the deposits that they are associated with mean it is inevitable that the design and construction of many projects will be influenced by their presence and nature. Tills and other glaciogenic deposits prove to be particularly challenging in this context for reasons that include: the spatial variability of the nature of the deposits; the wide range of particle sizes often included within a given soil, including large-sized particles; spatial variation in soil type and properties; variation in depth to rockhead and variable degrees of weathering and alteration; the presence of groundwater, that is misinterpreted as perched water, as well as sub-artesian and artesian conditions; the presence of solution features and fissures, partly or completely infilled with soft or loose material; and the presence of (often shallow) shear surfaces at residual strength. In this chapter, some of the more common problems and associated solutions associated with earthworks and man-made slopes, tunnels and underground structures, dams and reservoirs, foundations, and offshore engineering and installations are reviewed. It is important that great care is taken in addressing the influences of variability, complexity and uncertainty inherent in glacial/periglacial soil formations at all stages of the construction process, from feasibility to end-of-project activities, such as preparation of the as-built drawings.