Ground models for the design and construction of a high-speed rail link

Abstract

Purpose of survey Engineering geomorphological, geological and geotechnical information, pertinent to a long linear engineering project, was required to provide support to a Parliamentary Bill and assist the future design and construction of the Channel Tunnel Rail Link. A wide variety of reports, maps and borehole logs had been collated for locations in the vicinity of the route alignment. These were to be supplemented with Phase I ground investigations for limited locations along the route during the winter of 1993/94. Phase I information was to be incorporated with the desk study information to provide an initial classification of the route geomorphology and ground conditions, and provide a sensible basis from which to design subsequent Phase II ground investigations. The site The Channel Tunnel Rail Link (CTRL) is to be constructed between St Pancras and the Channel Tunnel Railway Terminal at Cheriton, near Folkestone. The CTRL is a high-speed railway, 108 km in length, and its construction will incorporate a variety of engineered structures. The route traverses a wide range of topography, and solid and drift geology, which produce a wide variety of ground conditions to be considered for design and construction purposes. At a macroscale the CTRL is located in three distinct geomorphological areas: the London Basin, the North Downs and the northern limb of the Weald. A wide variety of solid and drift geologies were evident from available British Geological Survey mapping: these included Lower London Tertiary deposits. Pleistocene Terrace deposits and recent alluvium in