TUNNELLING IN CHALK . TUNNEL CONSTRUCTION 90. PAPERS PRESENTED AT THE TUNNEL CONSTRUCTION 90 CONFERENCE, ORGANIZED BY THE INSTITUTION OF MINING AND METALLURGY, LONDON, 3-4 APRIL, 1990

The paper introduces the geology, engineering geology and engineering properties of chalks found in the United Kingdom. Then, by reference to a number of case studies, for works located in the Upper, Middle and Lower Chalks, the more important factors influencing design and construction of underground works in chalk are discussed. These case studies include (a) the Thames cable tunnel, a small tunnel in Peckham and New Cross, South London, and the Portabello Outfall at Brighton, all in Upper Chalk; (b) Lewis Road Tunnel, through Upper and Middle Chalk; (c) Killingholme Gas Storage caverns, in Middle Chalk, and (d) the Channel Tunnel, through Lower Chalk. Based on the limited case data, conclusions are drawn to the nature of the commonly faced difficulties and how these might best be overcome. For the covering abstract of the conference see IRRD 828810.