ABSTRACT
Vimy Ridge was a critical battlefield on the Western Front during the first World War. The final battle (April 9-12, 1917) is a critical milestone in the building of Canada as a nation but was also a major turning point in the seemingly endless trench warfare of the day. The details of the final battle on the ground is well documented in literature, on television and in the movies of today. Less known is the underground warfare that took place at Vimy and across the front lines of WWI. Both sides used tunnelling to supply the front lines, to provide shelter for troops and to advance attacks under the enemy lines. The construction of the tunnels, the strategic design and the long- term stability and current status are matters of great interest. This work was brought about by a need to assess the potential for cave-ins or collapses during restoration works on the Vimy Ridge Monument. The tunnel layout and designs employed by both German and Allied forces are described. The tunnelling challenges of the day are discussed and the current mechanics of instability and long-term prognosis are explored along with a summary of modern site investigations and analysis. This investigation is undertaken within the important historical and human context of the tunnel network.
