Small strain stiffness of loessic soils across South East England

Loess soils, commonly known as brickearth in the UK, have been modestly distributed across South, East, and South East England and are typically reworked with limited collapsibility. The High Speed Rail 2 alignment will cut in to Buckinghamshire and Hertfordshire where loess and loess-like drifts have been distributed in pockets. Serviceability of the high speed transportation infrastructure is dependent on soil small strain stiffness, 𝐺ₘₐₓ. Little is known about the magnitude and variation of 𝐺ₘₐₓ with depth, and its relevance to mineralogical variations of loess across the regions and along depth profiles.In this paper, a series of vertical profiles for 𝐺ₘₐₓ in lower and upper loessic sequences of South East England are generated using systematically collated semi-empirical equations and ground investigation data. Profiles are then contrasted with in-situ measured shear wave velocityand 𝐺ₘₐₓ. Discrepancy between measured and derived 𝐺ₘₐₓ are discussed and general implications are drawn out. Findings from this research inform ground and geotechnical engineers with an interest in performance-based design of engineered earth systems on loess and advanced HS and HSS soil models.