Getting through

Abstract

Tunnelling works required during the improvement of the A55 North Wales Coast Road, U.K., are described. Three major tunnels were built, at Pen-y-Clip, Penmaenbach and Conwy. The first and third were initally proposed as viaducts, but environmental pressures prompted an immersed-tube tunnel solution at Conwy and rock tunnelling at Pen-y-Clip. Construction methods used and difficulties encountered are summarized. (D.W.Taylor)