Geotechnical control of a major railway project involving tunnel works in Hong Kong

The geological sequence along the alignment generally comprises the following principal geotechnical units:

– fill (generally a few metres thick but up to 20 m thick at the West Kowloon Reclamation site);

– marine deposits and alluvium (described as clayey/silty sand and sandy silt/clay with some gravel, mainly found along Salisbury Road but also present locally near Haiphong Road and undredged pockets at the WKN Station);

– residual soil and saprolite, mainly completely to highly decomposed granite; and

– moderately decomposed to fresh medium-grained granite.