Colorado Tunnels Case History

This paper presents an overview of thirteen major tunnels in Colorado. The purpose of the paper is to document for easy reference the salient characteristics of the runnels for future reference and for comparison with potential future project. Included in the review of are: a summary of the ground conditions, runnel length and size, construction methods, support and lining types, and costs. Ail of the tunnels are situated in rock including shale, granite, gneiss, quartzite, and volcanic tuff. Review of these tunnels reveals changes in technologies few ground support and tunnel lining consistent with the industry. Additionally, it is noted that most of the tunnels used drill and blast excavation methods. However, if constructed with current technologies some of these tunnels, especially the long water tunnels, would likely be excavated with tunnel boring machines. Continued growth of Colorado's population with parallel needs for upgraded infrastructure in a mountainous area will likely result in more Colorado tunnels.