Tunnelling is a high risk business. Success depends crucially on the nature of the ground through which the tunnel is being driven. The cost of a thorough site investigation is usually only a small fraction of the cost of the construction work but this crucial phase of a project is often given too low a priority. This text provides a review of tunnelling contracts, particularly those for sewerage and drainage tunnels. It reviews site investigation methods, contract preparation and tender evaluation, tunnel costruction, claims and records, and the post-construction phase. Examples of good and...