Introduction

Eight to hundred years ago underground construction work was mostly associated with mining activities. In the last decades, however, tunnelling has become a more important activity within the field of underground construction work. Tunnels are driven for road and rail, sewer and water supply, hydro electric power projects, mountain caverns for industrial, recreational and storage purposes and as transport and storage systems for oil and gas. A number of these tunnel sites are underneath or close to inhabited buildings or industrial installations. Such conditions require a good technical judgment and knowledge of tunnel driving together with careful planning, to ensure safe and satisfactory results.