Applying the HS2 legacy to the North of England through the Mercia Mudstone Group

The Mercia Mudstone Group in the UK extends from the south coast to the Midlands where it bifurcates and continues through the North of England. The Mott MacDonald SYSTRA Design Joint Venture is working on behalf of Balfour Beatty VINCI, High Speed 2 (HS2) Limited's main works civils contractor for the West Midlands. BBV is constructing 90km of civils infrastructure to support the high speed railway between Long Itchington, in Warwickshire, the centre of Birmingham and on to Staffordshire. This crosses the Worcester/Knowle basins of the Mercia Mudstone Group. The Mercia Mudstone Group is known to possess a stratigraphy of varying lithologies within each geological formation. The HS2 project has gathered unprecedented quantities of geotechnical data on the Mercia Mudstone Group. By comparing this data with published literature, it has been highlighted how some geotechnical properties for engineering design vary by formation. A review of the SPT N-undrained shear strength correlation has also been undertaken, which has shown the potential for high variability in the f ₁ factor. From this comparison with literature, the geotechnical parameters interpreted from the HS2 ground investigation appear to be representative of the Mercia Mudstone Group in other parts of the UK.